Qualitative Comparison of Cryostat- versus Snap-Frozen Neurosurgical Intraoperative Consultations

Background. Frozen sections (FS) are common in neurosurgery to address varied clinical concerns. Artifacts in central nervous system (CNS) FS can be severe and affect or hinder interpretation. We performed a case-control study using a semiquantitative scale: the Histologic Preservation Score (HPS), and a quantitative scale: the Ice Crystal Vacuolization Score (ICVS), to compare the histologic quality yielded by snap- versus cryostat freezing techniques. Material and Methods. All specimens were sectioned in 2 halves, one half was used for FS and the other for permanent evaluation. HPS assigns a distortion score to the FS sample using the non-frozen half as the comparator: 1  =  minimal, 2  =  slight, 3  =  moderate, 4 & 5  =  severe. The ICVS is the average size in µm of the 5 largest vacuoles/0.05 mm2, evaluated on digitized slides. Results. 86 CNS-FS were collected: 22 snap- and 64 cryostat-FS. Significant differences in HPS: 2.28 versus 2.84 (p <0.05) and ICVS 7.47 versus 14.56 (p < 0.001) were obtained for snap- versus cryostat-FS, respectively. HPS and ICVS showed a strong correlation: R2 = 0.63, p < 0.0001. Histologic distortion was worse for neuroglial than mesenchymal tissue by both methods; however, a significant difference was only observed in cryostat-FS: HPS: 3.23 versus 2.33, p < 0.001; ICVS: 16.86 μm versus 10.26 μm, p < 0.001. Conclusion. Snap-FS yields better histologic quality than cryostat-FS for CNS-FS, and the difference is more pronounced in neuroglial samples. HPS and ICVS correlate strongly, indicating that the histologic quality is inversely proportional to water-crystallization. These results may apply to other areas of surgical pathology.

Developmentally Arrested Basket/Stellate Cells in Postnatal Human Brain as Potential Tumor Cells of Origin for Cerebellar Hemangioblastoma in von Hippel-Lindau Patients

von Hippel-Lindau (VHL) disease is an autosomal dominant hereditary cancer disorder caused by a germline mutation in the VHL tumor suppressor gene. Loss of the wild-type allele results in VHL deficiency and the potential formation of cerebellar hemangioblastomas, which resemble embryonic hemangioblast proliferation and differentiation processes. Multiple, microscopic, VHL-deficient precursors, termed developmentally arrested structural elements (DASEs), consistently involve the cerebellar molecular layer in VHL patients, indicating the tumor site of origin. Unlike hemangioblastomas, however, cerebellar DASEs do not express brachyury, a mesodermal marker for hemangioblasts. In this study, neuronal progenitors occupying the molecular layer were investigated as tumor cells of origin. By immunohistochemistry, cerebellar DASEs and hemangioblastomas lacked immunoreactivity with antibody ZIC1 (Zic family member 1), a granule cell progenitor marker with concordance from oligonucleotide RNA expression array analyses. Rather, cerebellar DASEs and hemangioblastomas were immunoreactive with antibody PAX2 (paired box 2), a marker of basket/stellate cell progenitors. VHL cerebellar cortices also revealed PAX2-positive cells in Purkinje and molecular layers, resembling the histological and molecular development of basket/stellate cells in postnatal non-VHL mouse and human cerebella. These data suggest that VHL deficiency can result in the developmental arrest of basket/stellate cells in the human cerebellum and that these PAX2-positive, initiated cells await another insult or signal to form DASEs and eventually, tumors.

Multimodal Atlas of the Murine Inner Ear: From Embryo to Adult

The inner ear is a complex organ housed within the petrous bone of the skull. Its intimate relationship with the brain enables the transmission of auditory and vestibular signals via cranial nerves. Development of this structure from neural crest begins in utero and continues into early adulthood. However, the anatomy of the murine inner ear has only been well-characterized from early embryogenesis to post-natal day 6. Inner ear and skull base development continue into the post-natal period in mice and early adulthood in humans. Traditional methods used to evaluate the inner ear in animal models, such as histologic sectioning or paint-fill and corrosion, cannot visualize this complex anatomy in situ. Further, as the petrous bone ossifies in the postnatal period, these traditional techniques become increasingly difficult. Advances in modern imaging, including high resolution Micro-CT and MRI, now allow for 3D visualization of the in situ anatomy of organs such as the inner ear. Here, we present a longitudinal atlas of the murine inner ear using high resolution ex vivo Micro-CT and MRI.

Molecular Classification of Gliomas is Associated with Seizure Control: A Retrospective Analysis

Classically, histologic grading of gliomas has been used to predict seizure association, with low-grade gliomas associated with an increased incidence of seizures compared to high-grade gliomas. In 2016, WHO reclassified gliomas based on histology and molecular characteristics. We sought to determine whether molecular classification of gliomas is associated with preoperative seizure presentation and/or post-operative seizure control across multiple glioma subtypes. All gliomas operated at our institution from 2007 to 2017 were identified based on ICD 9 and 10 billing codes and were retrospectively assessed for molecular classification of the IDH1 mutation, and 1p/19q codeletion. Logistic regression models were performed to assess associations of seizures at presentation as well as post-operative seizures with IDH status and the new WHO integrated classification. Our study included 376 patients: 82 IDH mutant and 294 IDH wildtype. The presence of IDH mutation was associated with seizures at presentation [OR 3.135 (1.818-5.404), p < 0.001]. IDH-mutant glioblastomas presented with seizures less often than other IDH-mutant glioma subtypes grade II and III [OR 0.104 (0.032-0.340), p < 0.001]. IDH-mutant tumors were associated with worse post-operative seizure outcomes, demonstrated by Engel Class [OR 2.666 (1.592-4.464), p < 0.001]. IDH mutation in gliomas is associated with an increased risk of seizure development and worse post-operative seizure control, in all grades except for GBM.

Pineal teratoma with nephroblastic component in a newborn male: Case report and review of the literature

Neonatal germ cell tumors are rare and comprise both benign and malignant neoplasms. Teratoma with nephroblastoma is a malignant subset defined pathologically by the presence of nephroblastoma and teratoma elements. Although teratoma with nephroblastoma is most often found in the kidney, 24 of 59 reported cases are associated with extrarenal locations, such as the mediastinum or retroperitoneum. To our knowledge, this is the first patient in the literature with intracranial/pineal teratoma with nephroblastoma, which was managed with staged transcranial approaches resulting in gross total resection and no adjuvant therapy (surveillance observation imaging). We further augmented the patient's management by comprehensive genomic profiling of the tumor to better understand the molecular biology and explore options for targeted therapy.

Von Hippel-Lindau Disease: Current Challenges and Future Prospects

Understanding of molecular mechanisms of tumor growth has an increasing impact on the development of diagnostics and targeted therapy of human neoplasia. In this review, we summarize the current knowledge on molecular mechanisms and their clinical implications in von Hippel-Lindau (VHL) disease. This autosomal dominant tumor syndrome usually manifests in young adulthood and predisposes affected patients to the development of benign and malignant tumors of different organ systems mainly including the nervous system and internal organs. A consequent screening and timely preventive treatment of lesions are crucial for patients affected by VHL disease. Surgical indications and treatment have been evaluated and optimized over many years. In the last decade, pharmacological therapies have been evolving, but are largely still at an experimental stage. Effective pharmacological therapy as well as detection of biomarkers is based on the understanding of the molecular basis of disease. The molecular basis of von Hippel-Lindau disease is the loss of function of the VHL protein and subsequent accumulation of hypoxia-inducible factor with downstream effects on cellular metabolism and differentiation. Organs affected by VHL disease may develop frank tumors. More characteristically, however, they reveal multiple separate microscopic foci of neoplastic cell proliferation. The exact mechanisms of tumorigenesis in VHL disease are, however, still not entirely understood and knowledge on biomarkers and targeted therapy is scarce.

Seizure freedom from recurrent insular low-grade glioma following laser interstitial thermal therapy

Pediatric low-grade gliomas (LGGs) are found in approximately 1-3% of patients with childhood epilepsy that is often medically refractory. Magnetic resonance guided laser interstitial thermal therapy (MRgLITT) is a minimal access technique FDA-approved since 2007 to ablate soft tissue lesions including brain tumors and seizure foci in children. The authors describe the case of an 11-year-old boy who presented with focal right-sided seizures and was found to have a growing left insular mass determined to be a WHO grade II diffuse astrocytoma. After the initial open resection using frontotemporal craniotomy with transsylvian approach, gross total resection was achieved; however, the tumor recurred, as did the seizures. Six months postoperatively, the patient underwent laser ablation with MRgLITT for the recurrent tumor with complete removal. At both 1- and 6-months post re-operation, he has remained seizure free. MRgLITT management of LGG allows for both successfully reducing tumor burden and the amelioration of secondary seizures.

Isocitrate dehydrogenase 1 mutant glioblastomas demonstrate a decreased rate of pseudoprogression: a multi-institutional experience

BACKGROUND

Pseudoprogression (psPD) represents false radiologic evidence of tumor progression and is observed in some glioblastoma (GBM) patients after postoperative chemoradiation (CRT) with temozolomide (TMZ). The ambiguity of the psPD diagnosis confounds identification of true progression and may lead to unnecessary interventions. The association between psPD and isocitrate dehydrogenase 1 (IDH1) mutational (mut) status is understudied, and its incidence may alter clinical decision making.

METHODS

We retrospectively evaluated 120 patients with IDH1-mut (n = 60) and IDH1-wild-type (IDH-WT; [n = 60]) GBMs who received postoperative CRT with TMZ at 4 academic institutions. Response Assessment in Neuro-Oncology criteria were used to identify psPD rates in routine brain MRIs performed up to 90 days after CRT completion.

RESULTS

Within 90 days of completing CRT, 9 GBM patients (1 [1.7%] IDH1-mut and 8 [13.3%] IDH1-WTs) demonstrated true progression, whereas 17 patients (3 [5%] IDH1-muts and 14 [23.3%] IDH1-WTs) demonstrated psPD (P  =  .004). IDH1-mut GBMs had a lower probability of psPD (hazard ratio: 0.173, 95% CI, 0.047-0.638, P = .008). Among the patients with radiologic signs suggestive of progression (n = 26), psPD was found to be the cause in 3 of 4 (75.0%) of the IDH1-mut GBMs and 14 of 22 (63.6%) of the IDH1-WT GBMs (P = .496). Median overall survival for IDH1-mut and IDH1-WT GBM patients was 40.3 and 23.0 months, respectively (P  < .001).

CONCLUSIONS

IDH1-mut GBM patients demonstrate lower absolute rates of psPD expression. Irrespective of GBM subtype, psPD expression was more likely than true progression within 90 days of completing CRT. Continuing adjuvant treatment for IDH1-mut GBMs is suggested if radiologic progression is suspected during this time interval.

A Systematic Review of Sellar and Parasellar Brown Tumors: An Analysis of Clinical, Diagnostic, and Management Profiles

OBJECTIVE

To systematically review and analyze clinical, diagnostic, and management trends in sellar and parasellar brown tumors reported in existing literature.

METHODS

In this systematic review, PubMed, Ovid MEDLINE, Scopus, and Google Scholar databases were searched for reported cases of sellar/parasellar brown tumors. Relevant titles and abstracts were screened in accordance to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses protocol. Articles meeting inclusion criteria were subjected to data extraction, summarization, and analysis. A rare case of parasellar brown tumor was also presented.

RESULTS

Eight reports (including the current report) were eligible for inclusion. Mean patient age was 42.75 years. Reported symptoms included visual disturbances (n = 6), headache (n = 5), fatigue (n = 3), nausea/vomiting (n = 2), chest pain (n = 1), neck pain (n = 1), and dysphagia (n = 1). In cases where computed tomography findings were provided (n = 6), lesions were noted to be expansile and lytic. Lesions were hyperintense on T2-weighted magnetic resonance imaging (66.7%) and demonstrated contrast enhancement (83.3%). Histology unanimously showed multinucleated giant cells in a fibrovascular connective tissue stroma. Dramatic symptom resolution was noted in all patients who underwent resection of the sellar/parasellar brown tumor (n = 4; 50%).

CONCLUSIONS

Sellar/parasellar brown tumors are a rare, tertiary manifestation of hyperparathyroidism and can be elusive to diagnose. Diagnosis requires a high index of clinical suspicion in addition to comprehensive biochemical testing, imaging, and histopathologic analysis. Surgical extirpation is favored in cases where the lesion is causing compressive symptoms, or if it is unresponsive to management of hyperparathyroidism.

Convection-enhanced delivery of botulinum toxin serotype A into the nonhuman primate cisterna magna and hippocampus

OBJECTIVE

Botulinum toxin serotype A (BoNT/A) was reported to raise the seizure threshold when injected into the seizure focus of a kindled rodent model. Delivering BoNT/A to the nonhuman primate (NHP) central nervous system via convection-enhanced delivery (CED) has not been performed. The objective of this study was to determine the toxicity and distribution characteristics of CED of BoNT/A into the NHP hippocampus and cisterna magna.

METHODS

Escalating BoNT/A doses were delivered by CED into the NHP hippocampus (n = 4) and cisterna magna (n = 5) for behavioral and histological assessment and to determine the highest nonlethal dose (LD0) and median lethal dose (LD50). Hippocampal BoNT/A was coinfused with Gd-albumin, a surrogate MRI tracer. Gd-albumin and radioiodinated BoNT/A (125I-BoNT/A) were coinfused into the hippocampus of 3 additional NHPs to determine BoNT/A distribution by in vivo MRI and postmortem quantitative autoradiography. Scintillation counting of CSF assessed the flow of 125I-BoNT/A from the hippocampus to CSF postinfusion.

RESULTS

LD0 and LD50 were 4.2 and 18 ng/kg, and 5 and > 5 ng/kg for the NHP hippocampus and cisterna magna, respectively. Gd-albumin and 125I-BoNT/A completely perfused the hippocampus (155-234 mm3) in 4 of 7 NHPs. Fifteen percent of BoNT/A entered CSF after hippocampal infusion. The MRI distribution volume of coinfused Gd-albumin (VdMRI) was similar to the quantitative autoradiography distribution of 125I-BoNT/A (VdQAR) (mean VdMRI = 139.5 mm3 [n = 7]; VdQAR = 134.8 mm3 [n = 3]; r = 1.00, p < 0.0001). No infusion-related toxicity was identified histologically except that directly attributable to needle placement.

CONCLUSIONS

Gd-albumin accurately tracked BoNT/A distribution on MRI. BoNT/A did not produce CNS toxicity. BoNT/A LD0 exceeded 10-fold the dose administered safely to humans for cosmesis and dystonia.

Ex vivo Dynamics of Human Glioblastoma Cells in a Microvasculature-on-a-Chip System Correlates with Tumor Heterogeneity and Subtypes

The perivascular niche (PVN) plays an essential role in brain tumor stem-like cell (BTSC) fate control, tumor invasion, and therapeutic resistance. Here, a microvasculature-on-a-chip system as a PVN model is used to evaluate the ex vivo dynamics of BTSCs from ten glioblastoma patients. BTSCs are found to preferentially localize in the perivascular zone, where they exhibit either the lowest motility, as in quiescent cells, or the highest motility, as in the invasive phenotype, with migration over long distance. These results indicate that PVN is a niche for BTSCs, while the microvascular tracks may serve as a path for tumor cell migration. The degree of colocalization between tumor cells and microvessels varies significantly across patients. To validate these results, single-cell transcriptome sequencing (10 patients and 21 750 single cells in total) is performed to identify tumor cell subtypes. The colocalization coefficient is found to positively correlate with proneural (stem-like) or mesenchymal (invasive) but not classical (proliferative) tumor cells. Furthermore, a gene signature profile including PDGFRA correlates strongly with the "homing" of tumor cells to the PVN. These findings demonstrate that the model can recapitulate in vivo tumor cell dynamics and heterogeneity, representing a new route to study patient-specific tumor cell functions.

Ex vivo Dynamics of Human Glioblastoma Cells in a Microvasculature-on-a-Chip System Correlates with Tumor Heterogeneity and Subtypes

The perivascular niche (PVN) plays an essential role in brain tumor stem-like cell (BTSC) fate control, tumor invasion, and therapeutic resistance. Here, a microvasculature-on-a-chip system as a PVN model is used to evaluate the ex vivo dynamics of BTSCs from ten glioblastoma patients. BTSCs are found to preferentially localize in the perivascular zone, where they exhibit either the lowest motility, as in quiescent cells, or the highest motility, as in the invasive phenotype, with migration over long distance. These results indicate that PVN is a niche for BTSCs, while the microvascular tracks may serve as a path for tumor cell migration. The degree of colocalization between tumor cells and microvessels varies significantly across patients. To validate these results, single-cell transcriptome sequencing (10 patients and 21 750 single cells in total) is performed to identify tumor cell subtypes. The colocalization coefficient is found to positively correlate with proneural (stem-like) or mesenchymal (invasive) but not classical (proliferative) tumor cells. Furthermore, a gene signature profile including PDGFRA correlates strongly with the "homing" of tumor cells to the PVN. These findings demonstrate that the model can recapitulate in vivo tumor cell dynamics and heterogeneity, representing a new route to study patient-specific tumor cell functions.

Chordoma of the corpus callosum: case report

Chordomas are neoplasms that typically arise from midline skeletal structures and rarely originate within the intradural compartment of the CNS. A chordoma arising from the corpus callosum has not been previously described. The authors report the surgical management of a chordoma originating within the splenium of the corpus callosum. To determine the incidence and distribution of intracranial intradural chordoma, a literature search for additional cases was performed. MEDLINE was searched using the MeSH keyword "chordoma," yielding 2010 articles. These articles were screened for cases of primary intradural chordoma rostral to the craniocervical junction, which led to the identification of 46 relevant articles. The authors report the case of a 69-year-old man who initially presented with nonspecific neurological symptoms including spatial disorientation and cognitive decline. These symptoms eventually prompted intracranial imaging, including MRI, which revealed a ring-enhancing, heterogeneous, cystic mass localized within the splenium of the corpus callosum and extending into the bilateral ventricles. The lesion was believed to represent a high-grade glioma and the patient underwent a left interhemispheric approach and subtotal resection. After pathologic evaluation confirmed a diagnosis of an anaplastic chordoma, the patient underwent further resection. A gross-total resection (GTR) was achieved with a transfalcine approach to the contralateral portion of the tumor. Postoperatively, the patient had a partial left homonymous quadrantanopsia, but was otherwise at his neurological baseline. Proton beam radiotherapy was performed to the resection cavity but diffuse intraventricular disease ensued. The results of a literature search suggest that a chordoma arising in the corpus callosum has not been previously described. The present case demonstrates that chordomas can occur in the corpus callosum, and illustrates the utility of a transfalcine approach for GTR of lesions in this location, as well as the need for improved strategies to prevent intraventricular dissemination.

Fatal cryptococcal meningitis in an AIDS patient complicated with immune reconstitution syndrome refractory to prolonged amphotericin B treatment

Cryptococcus neoformans is a ubiquitous encapsulated environmental yeast that can cause severe central nervous system disease, primarily in immune compromised hosts. In patients with AIDS, the spectrum of cryptococcal central nervous system disease includes meningitis, cystic lesions, and mass-like cryptococcomas. We report a fatal case of meningitis and cerebritis caused by C. neoformans in an AIDS patient refractory to multiple courses of liposomal amphotericin B despite immune recovery with antiretroviral therapy. This case highlights ongoing diagnostic and therapeutic challenges in the face of treatment failure for cryptococcal meningitis and reinforces the need for improved treatment approaches.

Integrated genomic analyses of de novo pathways underlying atypical meningiomas

This corrects the article DOI: 10.1038/ncomms14433.

Surgical Management of Carney Complex-Associated Pituitary Pathology

BACKGROUND

Carney complex (CNC) is a familial neoplasia syndrome that is associated with pituitary-associated hypersecretion of growth hormone (GH) (acromegaly). The underlying cause of pituitary GH hypersecretion and its management have been incompletely defined.

OBJECTIVE

To provide biological insight into CNC-associated pituitary pathology and improve management, we analyzed findings in CNC patients who underwent transsphenoidal surgery.

METHODS

Consecutive CNC patients at the National Institutes of Health with acromegaly and imaging evidence of a pituitary adenoma(s) who underwent transsphenoidal resection of tumor(s) were included. Prospectively acquired magnetic resonance imaging and biochemical, surgical, and histological data were analyzed.

RESULTS

Seven acromegalic CNC patients (2 male, 5 female) were included. The mean age at surgery was 29.7 years (range, 18-44 years). The mean follow-up was 4.7 years (range, 0.2-129 months). Magnetic resonance imaging revealed a single pituitary adenoma in 4 patients and multiple pituitary adenomas in 3 patients. Whereas patients with single discrete pituitary adenomas underwent selective adenomectomy, patients with multiple adenomas underwent selective adenomectomy of multiple tumors, as well as partial or total hypophysectomy. All adenomas were either GH and prolactin positive or exclusively prolactin positive. Pituitary tissue surrounding the adenomas in patients with multiple adenomas revealed hyperplastic GH- and prolactin-positive tissue.

CONCLUSION

CNC-associated acromegaly results from variable pituitary pathology, including a single GH-secreting adenoma or multiple GH-secreting adenomas and/or GH hypersecretion of the pituitary gland surrounding multiple adenomas. Although selective adenomectomy is the preferred treatment for cases of GH-secreting adenomas, multiple adenomas with associated pituitary gland GH hypersecretion may require partial or complete hypophysectomy to achieve biochemical remission.

Longitudinal analysis of treatment-induced genomic alterations in gliomas

Background

Glioblastoma multiforme (GBM) constitutes nearly half of all malignant brain tumors and has a median survival of 15 months. The standard treatment for these lesions includes maximal resection, radiotherapy, and chemotherapy; however, individual tumors display immense variability in their response to these approaches. Genomic techniques such as whole-exome sequencing (WES) provide an opportunity to understand the molecular basis of this variability.

Methods

Here, we report WES-guided treatment of a patient with a primary GBM and two subsequent recurrences, demonstrating the dynamic nature of treatment-induced molecular changes and their implications for clinical decision-making. We also analyze the Yale-Glioma cohort, composed of 110 whole exome- or whole genome-sequenced tumor-normal pairs, to assess the frequency of genomic events found in the presented case.

Results

Our longitudinal analysis revealed how the genomic profile evolved under the pressure of therapy. Specifically targeted approaches eradicated treatment-sensitive clones while enriching for resistant ones, generated due to chromothripsis, which we show to be a frequent event in GBMs based on our extended analysis of 110 gliomas in the Yale-Glioma cohort. Despite chromothripsis and the later acquired mismatch-repair deficiency, genomics-guided personalized treatment extended survival to over 5 years. Interestingly, the case displayed a favorable response to immune checkpoint inhibition after acquiring mismatch repair deficiency.

Conclusions

Our study demonstrates the importance of longitudinal genomic profiling to adjust to the dynamic nature of treatment-induced molecular changes to improve the outcomes of precision therapies.

Electronic supplementary material

The online version of this article (doi:10.1186/s13073-017-0401-9) contains supplementary material, which is available to authorized users.

Novel biomarker identification using metabolomic profiling to differentiate radiation necrosis and recurrent tumor following Gamma Knife radiosurgery

OBJECTIVE Following an initial response of brain metastases to Gamma Knife radiosurgery, regrowth of the enhancing lesion as detected on MRI may represent either radiation necrosis (a treatment-related inflammatory change) or recurrent tumor. Differentiation of radiation necrosis from tumor is vital for management decision making but remains difficult by imaging alone. In this study, gas chromatography with time-of-flight mass spectrometry (GC-TOF) was used to identify differential metabolite profiles of the 2 tissue types obtained by surgical biopsy to find potential targets for noninvasive imaging. METHODS Specimens of pure radiation necrosis and pure tumor obtained from patient brain biopsies were flash-frozen and validated histologically. These formalin-free tissue samples were then analyzed using GC-TOF. The metabolite profiles of radiation necrosis and tumor samples were compared using multivariate and univariate statistical analysis. Statistical significance was defined as p ≤ 0.05. RESULTS For the metabolic profiling, GC-TOF was performed on 7 samples of radiation necrosis and 7 samples of tumor. Of the 141 metabolites identified, 17 (12.1%) were found to be statistically significantly different between comparison groups. Of these metabolites, 6 were increased in tumor, and 11 were increased in radiation necrosis. An unsupervised hierarchical clustering analysis found that tumor had elevated levels of metabolites associated with energy metabolism, whereas radiation necrosis had elevated levels of metabolites that were fatty acids and antioxidants/cofactors. CONCLUSIONS To the authors' knowledge, this is the first tissue-based metabolomics study of radiation necrosis and tumor. Radiation necrosis and recurrent tumor following Gamma Knife radiosurgery for brain metastases have unique metabolite profiles that may be targeted in the future to develop noninvasive metabolic imaging techniques.

Recurrent somatic mutations in POLR2A define a distinct subset of meningiomas

RNA polymerase II mediates the transcription of all protein-coding genes in eukaryotic cells, a process that is fundamental to life. Genomic mutations altering this enzyme have not previously been linked to any pathology in humans, which is a testament to its indispensable role in cell biology. On the basis of a combination of next-generation genomic analyses of 775 meningiomas, we report that recurrent somatic p.Gln403Lys or p.Leu438_His439del mutations in POLR2A, which encodes the catalytic subunit of RNA polymerase II (ref. 1), hijack this essential enzyme and drive neoplasia. POLR2A mutant tumors show dysregulation of key meningeal identity genes, including WNT6 and ZIC1/ZIC4. In addition to mutations in POLR2A, NF2, SMARCB1, TRAF7, KLF4, AKT1, PIK3CA, and SMO, we also report somatic mutations in AKT3, PIK3R1, PRKAR1A, and SUFU in meningiomas. Our results identify a role for essential transcriptional machinery in driving tumorigenesis and define mutually exclusive meningioma subgroups with distinct clinical and pathological features.

Abstract 2393: Kidneys of VHL patients reveal the origin of renal clear cell carcinoma

VHL disease is a classic tumor suppressor gene syndrome characterized by development of specific types of tumors in selective organs with nervous system and kidney being most consistently affected. Detailed studies on human spinal cord and cerebellum have previously revealed earliest stages of CNS tumorigenesis and the morphologic sequence resulting in development of frank tumors.

To elucidate earliest stages of renal clear cell carcinoma, we performed a similar approach in kidney tissues of four VHL patients and three sporadic control cases. From all cases, blocks of interest were procured, followed by serial sectioning and 3dimensional reconstruction of potential precursor lesions. The results reveal an abundance of foci with aberrant mesonephric clear cell proliferations that initially develop along the tubular lining, but have the potential to aggregate within individual tubules. This stage is followed by microscopic invasive clear cell aggregations which represent tumor precursor structures.

This study presents evidence for a consistent morphologic sequence for renal clear cell carcinogenesis. Molecular analysis of early steps within this sequence will allow for identification of earliest genetic and proteomic changes in the future. Therapeutic targeting of earliest changes may allow to develop preventive strategies for renal cancer development for VHL patients, potentially also for the non-VHL population.

Citation Format: Mayyan Mubarak, Samuel Sommaruga, David Voigt, Xiacao Xu, Steve Kim, Ailin Song, Alexander O. Vortmeyer. Kidneys of VHL patients reveal the origin of renal clear cell carcinoma. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 2393.

Possible Interaction of Anti-PD-1 Therapy with the Effects of Radiosurgery on Brain Metastases

Delayed radiation-induced vasculitic leukoencephalopathy related to stereotactic radiosurgery (SRS) of brain metastases has been reported to manifest clinically 9 to 18 months after treatment. Immune-modulating therapies have been introduced to treatment regimens for malignancies with metastatic predilection to the brain. The interaction of these systemic therapies with other modalities of treatment for brain metastases, namely, SRS, has not been fully characterized. We report two patients with metastatic malignancies to the brain who received SRS followed by immunotherapy with monoclonal antibodies (mAb) to programmed death 1 (PD-1). Both patients appeared to have early clinical and radiologic progression of their treated lesions, which was highly suspicious for tumor progression. Both patients underwent surgical resection of their lesions and the material was submitted for histopathologic examination. Pathologic examination in both cases showed predominantly radiation-induced changes characterized by reactive astrocytosis and vascular wall infiltration by T lymphocytes. The accelerated response to SRS in these two patients was temporally related to the initiation of immunotherapy. We propose a possible biologic interaction between SRS and the PD-1 mAbs. Additionally, awareness of this potential occurrence is critical for accurate interpretation and proper management of clinical and radiologic findings in these patients. Cancer Immunol Res; 4(6); 481-7. ©2016 AACR.

Melanoma Brain Metastasis Pseudoprogression after Pembrolizumab Treatment

The role of immunotherapy in treatment of brain metastases is unknown because most trials exclude patients with active brain lesions. As new immunomodulating agents gain approval for many malignancies, it is important to know if they have unique effects in the central nervous system (CNS). Here, we present a case of a patient with progressing brain metastases treated with a single cycle of pembrolizumab, who presented with mental status changes 11 days thereafter. MRI of the brain showed enlargement of CNS lesions with intense central enhancement and diffuse perilesional edema. Histologic evaluation of a resected lesion revealed isolated clusters of tumor cells surrounded by reactive astrocytosis, scattered inflammatory cells, and an abundance of microglial cells. Given the increasing use of immune checkpoint inhibitors in patients with brain metastases from melanoma and other diseases, recognition of pseudoprogression and management with immune suppression are essential.

A 10-minute prototype assay for tissue degradation monitoring in clinical specimens

We recently identified alpha II spectrin as a Tissue Degradation Indicator (TDI) and demonstrated that intrinsic spectrin-breakdown levels reliably reveal tissue degradation status in biospecimens. With the present study, we introduce an in vitro biological assay to mimic the endogenous spectrin-breakdown process and serve as degradation monitor (DM). By initiating the DM at the time of specimen collection and by attaching the DM to respective specimens, specimen degradation can be assessed by DM readout without specimen consumption. Using a protease inhibitory assay and protease-targeted immunoassays, we identified calpain as the protease responsible for degradation-induced spectrin breakdown. To recapitulate spectrin degradation in vitro, we developed several enzymatic assays in test tubes by incubating recombinant spectrins and synthetic Fluorescence Resonance Energy Transfer (FRET)-based spectrin peptides with purified human and porcine calpains. The in vitro assays reliably performed in different environments for a limited time due to loss of calpain activity. To maintain longer calpain activity, we introduced cultured cells as calpain providers into the in vitro assays. Under a variety of degradative conditions, including 4°C, 13°C, 23°C, 29°C, 37°C, freezing, and freeze-thaw steps, we compared the use of this prototype DM to the intrinsic spectrin cleavage assay (ISCA) in specimen degradation assessment using animal models. A strong correlation (r=0.9895) was detected between the DM-revealed degradation and the ISCA-revealed degradation. Notably, the DM-based degradation assessment takes only 10min and does not jeopardize the tissue itself, whereas the ISCA-based degradation assessment needs to sacrifice tissues and takes several hours to accomplish. Our data suggests the application of an in vitro degradation monitor for fast, real time, and non-invasive assessment of specimen degradation. This observation could lead to a transformative product dedicated to biospecimen quality control. This study also addresses critical, yet unmet needs for developing a universal standard for specimen degradation measurement.

Epidermal growth factor receptor as a novel molecular target for aggressive papillary tumors in the middle ear and temporal bone

Adenomatous tumors in the middle ear and temporal bone are rare but highly morbid because they are difficult to detect prior to the development of audiovestibular dysfunction. Complete resection is often disfiguring and difficult because of location and the late stage at diagnosis, so identification of molecular targets and effective therapies is needed. Here, we describe a new mouse model of aggressive papillary ear tumor that was serendipitously discovered during the generation of a mouse model for mutant EGFR-driven lung cancer. Although these mice did not develop lung tumors, 43% developed head tilt and circling behavior. Magnetic resonance imaging (MRI) scans showed bilateral ear tumors located in the tympanic cavity. These tumors expressed mutant EGFR as well as active downstream targets such as Akt, mTOR and ERK1/2. EGFR-directed therapies were highly effective in eradicating the tumors and correcting the vestibular defects, suggesting these tumors are addicted to EGFR. EGFR activation was also observed in human ear neoplasms, which provides clinical relevance for this mouse model and rationale to test EGFR-targeted therapies in these rare neoplasms.

Targeting secondary injury in intracerebral haemorrhage--perihaematomal oedema

Perihaematomal oedema (PHO) is an important pathophysiological marker of secondary injury in intracerebral haemorrhage (ICH). In this Review, we describe a novel method to conceptualize PHO formation within the framework of Starling's principle of movement of fluid across a capillary wall. We consider progression of PHO through three stages, characterized by ionic oedema (stage 1) and progressive vasogenic oedema (stages 2 and 3). In this context, possible modifiers of PHO volume and their value in identifying patients who would benefit from therapies that target secondary injury are discussed; the practicalities of using neuroimaging to measure PHO volume are also considered. We examine whether PHO can be used as a predictor of neurological outcome following ICH, and we provide an overview of emerging therapies. Our discussion emphasizes that PHO has clinical relevance both as a therapeutic target, owing to its augmentation of the mass effect of a haemorrhage, and as a surrogate marker for novel interventions that target secondary injury.

Proteomic comparison of oligodendrogliomas with and without 1pLOH

OBJECTIVE

Chemoresistance is a widespread therapeutic challenge in glial tumors. The molecular basis of chemoresistance is poorly understood, precluding advances in glioma treatment and leaving gliomas among the most lethal tumors. Oligodendrogliomas provide a unique model to study the molecular basis of chemoresistance, as there are two distinct genetic subtypes with significant differences in chemosensitivity. Despite a high morphological similarity, tumors with allelic loss on the short arm of chromosome 1 (1pLOH) are more chemosensitive than those without 1pLOH.

METHODS

In order to identify candidate proteins potentially responsible for glioma chemosensitivity, we compared the proteome of four oligodendrogliomas with and five without 1pLOH using comparative proteomic profiling. Proteomic analysis was performed by two-dimensional protein gel electrophoresis and subsequent computerized gel analysis for detection of distinguishing patterns of protein expression. Differentially expressed proteins were identified using Liquid Chromatography/Mass Spectrometry. Differential expression of select proteins was confirmed by Western blotting.

RESULTS

We identified seven candidate proteins that are overexpressed in oligodendrogliomas without 1pLOH. Two of these proteins (glyoxalase I and Rho GDP dissociation inhibitor) have previously been shown to enhance chemoresistance in other tumors. In turn, we identified twelve overexpressed proteins in tumors with 1pLOH that have previously been reported to induce chemosensitivity in other forms of human neoplasia.

CONCLUSIONS

These identified proteins are potential targets for pharmacological therapy and may also be useful as biomarkers for differentiation of chemoresistant and chemosensitive oligodendroglioma.

Proteomic profiling – A novel method for differential diagnosis?

Tumors with identical phenotype can have markedly different biologic behavior. The differentiation between hemangioblastoma, a benign vascular brain tumor, and renal cell carcinoma (RCC), a malignant tumor that can metastasize to the brain, is a well-known pathological quandary. We report a 59-year-old female with von Hippel-Lindau disease and known RCC. She presented with a cystic cerebellar tumor that had typical MRI appearance of a hemangioblastoma. Progressive symptoms led to surgical intervention. The histology included features consistent with either hemangioblastoma with epitheloid phenotype or atypical RCC metastasis mimicking hemangioblastoma. The discrepancy between the benign clinical course and the histologic phenotype could not be clearly resolved using conventional clinical techniques. We used proteomic profiling to clarify this diagnostic dilemma. We compared the proteomic expression pattern of the unknown lesion with the patterns of three typical hemangioblastomas and three typical RCCs by using selective tissue microdissection combined with two-dimensional proteomic profiling and protein sequencing. The results clearly indicated a protein profile consistent with RCC. Proteomics may complement pathological evaluation and characterization of tumors in the future. Furthermore, these results show that metastasis of malignant RCC is not necessarily equivalent to aggressive growth patterns.

Intracranial infantile hemangiopericytoma

Intracranial infantile hemangiopericytomas (HPCs) are exceedingly rare lesions. Only 11 cases have been previously reported in the literature. As such, little is known about the etiology, long-term prognosis, and optimal treatment paradigm. Clinically, they are consistently less aggressive than those in adults. The authors present the case of a 2-month-old boy with an intracranial HPC, review the available literature, discuss the evolving concepts of what defines an HPC, and offer a potential explanation to how HPC histology might relate to the clinical behavior of these lesions.

Significance of histology in determining management of lesions regrowing after radiosurgery

Brain metastases treated with stereotactic radiosurgery may show delayed enlargement on post-treatment imaging that is of ambiguous etiology. Histopathologic interpretation of brain specimens is often challenging due to the presence of significant radiation effects admixed with irradiated residual tumor of indeterminate viability. The purpose of this study was to assess the impact of histologic findings on clinical outcomes following resection of these lesions. Between 2004 and 2010, 690 patients with brain metastases were enrolled in a prospective gamma knife data repository, and lesions requiring excision were identified. Tissue specimens were divided into four groups based on the ratio of treatment related inflammatory changes (TRIC) to tumor cells, and subsequently patient outcomes were assessed. Of 2,583 metastases treated, 36 were excised due to symptomatic enlargement. Only TRIC, without residual evidence of tumor, was seen in 36 % (13/36) of specimens. Resection of these lesions resulted in 100 % local control in follow-up. Of the remaining 23 lesions that contained any viable-appearing tumor within the resected specimen, 8 recurred after resection. Lesions that enlarged in the first 6 months were more likely to contain higher amounts of residual tumor cells. Patients with even <2 % tumors cells on excision had significantly worse local control (75 vs. 100 %, p = 0.024) and survival (HR 0.27, p = 0.029) compared with those patients with exclusively TRIC. In summary, our findings underscore the importance of surgically obtaining tissue in a method that facilitates complete lesional interpretive histology in order to accurately guide ongoing patient management.

Radiologic and histologic consequences of radiosurgery for brain tumors

Progressively enlarging encephalopathic changes are now well-documented effects of gamma knife radiosurgery (GKRS) occurring ~3-30 months after treatment of both benign and malignant brain lesions. These changes can be variably associated with inflammatory demyelination and necrosis and/or recurrent tumor. While radiographic differentiation between encephalopathic changes and recurrent tumor is of high clinical relevance, confident interpretation of post-radiosurgery imaging changes can be challenging or even impossible in some cases. Gadolinium-enhanced MRI of these lesions reveals variable amounts of enhancing and non-enhancing components within these lesions that have not been clearly correlated with structural-pathologic change. The goal of this study is to characterize the histopathological changes associated with enhancing versus non-enhancing regions of GKRS-treated lesions. MRI images of patients with progressive, etiologically ambiguous brain lesions following GKRS were reviewed prior to explorative neurosurgery. Chosen for this study were lesions in which distinct areas of enhancement and non-enhancement of at least 5 mm in size could be identified (n = 16). Distinctly enhancing and non-enhancing areas were separately biopsied and histologically evaluated. Only cases with uniform histological results are presented in this study. Enhancing and non-enhancing areas in post GKRS lesions represent separate pathological changes. Radiographically enhancing areas correlate either with recurrent tumor growth or inflammatory demyelinating changes. Lack of radiographic enhancement correlates with coagulative necrosis if the sample is taken from the center of the lesion, or with reactive astrocytosis if the sample is taken from the periphery. Separate biopsy of enhancing and non-enhancing regions of post-GKRS encephalopathy was able to confirm that the pathologies in these areas are distinct. These findings allow for better-informed correlation of histological and radiological changes and a better understanding of post-treatment tissue pathology.

VHL-deficient vasculogenesis in hemangioblastoma

Hemangioblasts are capable of differentiation into vascular structures and blood. Patients with von Hippel-Lindau (VHL) disease develop hemangioblastomas which are composed of VHL-deficient tumor cells with protracted hemangioblastic differentiation potential. In a subset of these tumors, hemangioblastic differentiation is characterized by different stages of red blood cell formation. It has remained controversial, however, whether VHL-deficient hemangioblastic cells are similarly capable of differentiating into vascular cells and functioning vascular structures in vivo. By histologic, immunohistologic and microdissection-based genetic analysis of 60 VHL disease-associated hemangioblastomas, we re-examined the controversial question whether VHL-deficient neoplastic hemangioblastic cells are capable of vascular differentiation (vasculogenesis). In most tumors (n=47), there was no evidence of either vasculogenesis or hematopoiesis; tumor cells were either scattered between reactive angiogenetic vascular structures or arranged in solid clusters. A subset of tumors (n=13), however, revealed vaculogenetic structures that were composed of cuboidal or flat cells and frequently contained red blood cell precursors or mature red blood cells. Microdissection-based deletion analysis of epithelial cells confirmed them to be VHL-deficient tumor cells. Immunohistochemistry for CD31 was consistently negative in these structures, and no evidence could be obtained for connectivity with reactive vasculature. We demonstrate that hemangioblastic differentiation capacity of VHL-deficient hemangioblastic cells includes not only erythropoiesis, but also differentiation into primitive vasculogenetic structures. Tumor cells, however, do not appear to have the potential of terminal differentiation into mature and functional vascular structures.

Abstract 730: A prototype device for quality control of cancer specimens

Objective: Molecular degradation in cancer specimens may lead to misinterpretation of patients’ biological information. We have recently shown that utilization of the quantitative ratio between Tissue Degradation Indicators’ (TDIs’) intact form and their breakdown form(s) accurately reveals the stage of degradation in cancer specimens. We here propose to develop an enzymatic device built on one of the TDIs - alpha II spectrin (SPTAN1) - to monitor the degradation of cancer specimens, starting at the time of surgical resection. The device will allow specimen-users to assess the degradation stage of individual specimens prior to laboratory analyses. Approach: Proteolytic enzyme screening was conducted to identify the enzyme responsible for degradation-induced SPTAN1 breakdown. An in vitro enzymatic reaction was set up using the identified enzyme to catalyze overexpressed SPTAN1. The cleavage speed was monitored under various ambient temperatures at assigned time points. Correlation was studied between in vitro SPTAN1 breakdown and respective ambient conditions. A Fluorescence Resonance Energy Transfer (FRET)-based SPTAN1 peptide containing the proteolytic site was synthesized to replace the overexpressed SPTAN1 in above reaction. The enzymatic device was attached to experimental specimens and underwent assigned ambient exposures. SPTAN1 cleavage was measured by spectrophotometry. Correlation was studied among the SPTAN1 breakdown-induced fluorescence, the ambient impact, and the intrinsic TDI status. Further, FRET- SPTAN1 was injected into specimens in situ and the breakdown-induced fluorescent changes (catalyzed by local enzymes) were examined by fluorescence microscopy. Results: Calpain I was identified to be responsible for degradation-induced spectrin proteolysis. The in vitro enzymatic reaction can accurately reveal (following certain mathematic algorithm) the ambient temperature alteration and the exposure length via displaying a dynamic ratio between the breakdown and the intact SPTAN1. The introduction of FRET technology greatly facilitates the detection of spectrin breakdown reflected by breakdown-induced fluorescent signals. The FRET-device can properly reveal the ambient impact and the corresponding degradation inside the attached specimens. Local proteolytic enzymes in specimens are able to catalyze injected FRET- SPTAN1 and thereby the in situ approach imitates the in vitro enzymatic reaction and detects the ambient impact in specimens’ microenvironment. Conclusions: The prototype device yields a potentially transformative platform dedicated to specimen quality control. This foundational device may be attractive for commercialization and widely used throughout the basic and clinical cancer research communities. This effort also addresses critical, yet unmet needs for developing a universal standard for specimen degradation measurement.

Citation Format: Jie Li, Catherine Kil, Jia Sun, Michael Stankewich, Alexander O. Vortmeyer. A prototype device for quality control of cancer specimens. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 730. doi:10.1158/1538-7445.AM2013-730

Nervous system involvement in von Hippel-Lindau disease: pathology and mechanisms

Patients with von Hippel-Lindau disease carry a germline mutation of the Von Hippel-Lindau (VHL) tumor-suppressor gene. We discuss the molecular consequences of loss of VHL gene function and their impact on the nervous system. Dysfunction of the VHL protein causes accumulation and activation of hypoxia inducible factor (HIF) which can be demonstrated in earliest stages of tumorigenesis and is followed by expression of VEGF, erythropoietin, nitric oxide synthase and glucose transporter 1 in VHL-deficient tumor cells. HIF-independent functions of VHL, epigenetic inactivation of VHL, pVHL proteostasis, and links between loss of VHL function and developmental arrest are also described. A most intriguing feature in VHL disease is the occurrence of primary hemangioblastic tumors in the nervous system, the origin of which has not yet been entirely clarified, and current hypotheses are discussed. Endolymphatic sac tumors may extend into the brain, but originally arise from proliferation of endolymphatic duct/sac epithelium; the exact nature of the proliferating epithelial cell, however, also has remained unclear, as well as the question why tumors almost consistently develop in the intraosseous portion of the endolymphatic sac/duct only. The epitheloid clear cell morphology of both advanced hemangioblastoma and renal clear cell carcinoma can make the differential diagnosis challenging, recent developments in immunohistochemical differentiation are discussed. Finally, metastasis to brain may not only be caused by renal carcinoma, but may derive from VHL disease-associated pheochromocytoma/paraganglioma, or pancreatic neuroendocrine tumor.

High-throughput secretomic analysis of single cells to assess functional cellular heterogeneity

Secreted proteins dictate a range of cellular functions in human health and disease. Because of the high degree of cellular heterogeneity and, more importantly, polyfunctionality of individual cells, there is an unmet need to simultaneously measure an array of proteins from single cells and to rapidly assay a large number of single cells (more than 1000) in parallel. We describe a simple bioanalytical assay platform consisting of a large array of subnanoliter microchambers integrated with high-density antibody barcode microarrays for highly multiplexed protein detection from over a thousand single cells in parallel. This platform has been tested for both cell lines and complex biological samples such as primary cells from patients. We observed distinct heterogeneity among the single cell secretomic signatures that, for the first time, can be directly correlated to the cells' physical behavior such as migration. Compared to the state-of-the-art protein secretion assay such as ELISpot and emerging microtechnology-enabled assays, our approach offers both high throughput and high multiplicity. It also has a number of clinician-friendly features such as ease of operation, low sample consumption, and standardized data analysis, representing a potentially transformative tool for informative monitoring of cellular function and immunity in patients.

Intrinsic indicators for specimen degradation

Variable degrees of molecular degradation occur in human surgical specimens before clinical examination and severely affect analytical results. We therefore initiated an investigation to identify protein markers for tissue degradation assessment. We exposed 4 cell lines and 64 surgical/autopsy specimens to defined periods of time at room temperature before procurement (experimental cold ischemic time (CIT)-dependent tissue degradation model). Using two-dimensional fluorescence difference gel electrophoresis in conjunction with mass spectrometry, we performed comparative proteomic analyses on cells at different CIT exposures and identified proteins with CIT-dependent changes. The results were validated by testing clinical specimens with western blot analysis. We identified 26 proteins that underwent dynamic changes (characterized by continuous quantitative changes, isoelectric changes, and/or proteolytic cleavages) in our degradation model. These changes are strongly associated with the length of CIT. We demonstrate these proteins to represent universal tissue degradation indicators (TDIs) in clinical specimens. We also devised and implemented a unique degradation measure by calculating the quantitative ratio between TDIs' intact forms and their respective degradation-modified products. For the first time, we have identified protein TDIs for quantitative measurement of specimen degradation. Implementing these indicators may yield a potentially transformative platform dedicated to quality control in clinical specimen analyses.

Two-level thoracic pedicle subtraction osteotomy for progressive post-laminectomy kyphotic deformity following resection of an unusual thoracolumbar intradural extramedullary tumor

The authors report a case in which multilevel thoracic pedicle subtraction osteotomy (PSO) was performed to correct post-laminectomy kyphotic deformity in a 9-year-old boy presenting with worsening lower-extremity neurological deficits. Five years prior to presentation, the patient underwent multilevel thoracolumbar laminectomies for resection of an atypical teratoid/rhabdoid tumor (AT/RT), a rare lesion that typically occurs intracranially and has a poor prognosis, making this particular presentation unusual and the patient's subsequent postoperative course remarkable. No fusion was undertaken at the time of resection, given the patient's age and presumptive poor prognosis. Over the next 5 years, the patient developed progressive thoracolumbar kyphotic deformity, with a Cobb angle greater than 110°, despite bracing, and bilateral lower-extremity weakness requiring ankle-foot orthotics for continued ambulation due to progressive foot drop. Worsening gait and the onset of respiratory issues prompted surgical intervention. Multilevel thoracic PSO and thoracolumbar fusion were performed, resulting in improved lower-extremity function and correction of the kyphotic deformity to approximately 65°. This report outlines an unusual AT/RT presentation and postoperative course and also discusses literature related to PSO within the context of pediatric kyphotic deformity. The authors' experience supports the use of multilevel PSO with fusion as a potential treatment option for significant pediatric thoracolumbar kyphotic deformity requiring surgical correction.

Somatic GNAS mutation causes widespread and diffuse pituitary disease in acromegalic patients with McCune-Albright syndrome

CONTEXT

McCune-Albright syndrome (MAS) is caused by sporadic mutations of the GNAS. Patients exhibit features of acromegaly. In most patients, GH-secreting pituitary adenomas have been held responsible for this presentation. However, surgical adenomectomy rarely eliminates excess GH production.

OBJECTIVE

The aim of this study was to elucidate pituitary pathology in patients with MAS and to explain the basis of failure of adenomectomy to eliminate GH hypersecretion.

DESIGN AND SETTING

We conducted a case series at the National Institutes of Health.

INTERVENTION(S)

Interventions included medical therapy and transsphenoidal surgery.

PATIENTS AND MAIN OUTCOME MEASURES

We studied clinical and imaging features and the histology and molecular features of the pituitary of four acromegalic MAS patients.

RESULTS

We identified widespread and diffuse pituitary gland disease. The primary pathological changes were characterized by hyperplastic and neoplastic change, associated with overrepresentation of somatotroph cells in structurally intact tissue areas. Genetic analysis of multiple microdissected samples of any type of histological area consistently revealed identical GNAS mutations in individual patients. The only patient with remission after surgery received complete hypophysectomy in addition to removal of multiple GH-secreting tumors.

CONCLUSIONS

These findings indicate developmental effects of GNAS mutation on the entire anterior pituitary gland. The pituitary of individual cases contains a spectrum of changes with regions of normal appearing gland, hyperplasia, and areas of fully developed adenoma formation, as well as transitional stages between these entities. The primary change underlying acromegaly in MAS patients is somatotroph hyperplasia involving the entire pituitary gland, with or without development of somatotroph adenoma. Thus, successful clinical management, whether it is medical, surgical, or via irradiation, must target the entire pituitary, not just the adenomas evident on imaging.

Abstract 3609: Generation and characterization of a novel monoclonal antibody recognizing both the blood and tissue form of human PCBP-1

Background: Poly(rC)-binding protein-1 (PCBP-1) is a nucleic-acid-binding protein that localizes in nucleus and/or cytoplasm of cells. Shuttling between nucleus and cytoplasm has been related to its function in regulation of RNA transcription, translation and also implicated its involvement in cancer metastasis, progression and chemoresistance. In the present study, we investigated the levels and expression of PCBP-1 in breast carcinoma and its potential use as a biomarker in breast carcinoma differential diagnosis. Methods/Results: We generated a novel monoclonal antibody (mAb), AB-PCBP-1 using hybridoma technology and native protein in cell culture medium as immunogen. This mAb is of IgG1 (kappa) type. It specifically recognized both native and denatured human PCBP-1 protein and displayed high affinity as assessed by ELISA, immunohistochemistry assay, western blot and flow cytometry applications. Using this mAb in competitive ELISA, we showed for the first time that soluble PCBP-1 level is significantly increased in the plasma of metastatic breast cancer patients’ plasma. PCBP-1 is also expressed in metastatic breast carcinoma tissue by immunohistochemistry. Seventy percent of normal breast ducts and lobules expressed strong nuclear staining whereas cytoplasmic staining was less specific and found in most cancer tissues. We examined 90 cases of breast carcinoma tissues classified as either ductal and lobular carcinoma. To evaluate the immunoreactivity of PCBP-1, the staining intensity and intracellular distribution were compared and scored as 0, 1+, 2+ and 3+ based on intensity. Seventy nine % (60 out of 76) of ductal carcinomas showed strong cytoplasmic staining (2+ and 3+) and 45% also exhibited strong nuclear localization for PCBP-1. Lobular carcinomas (n=14), on the other hand, showed an exclusively nuclear staining pattern.Conclusion: AB-PCBP-1 mAb showed high performance in blood and tissue assays. PCBP-1 levels were significantly increased in blood and demonstrated a distinct pattern of expression related to histological tumor types, suggesting that PCBP-1 may be involved in a regulatory mechanism that differs in various subtypes of breast carcinoma. The results suggest the potential clinical use of PCBP-1 as a therapeutic target and/or a biomarker in blood and tissue for the diagnosis and prognosis of breast carcinoma.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3609. doi:1538-7445.AM2012-3609

Hereditary pituitary hyperplasia with infantile gigantism

CONTEXT

We report hereditary pituitary hyperplasia.

OBJECTIVE

The objective of the study was to describe the results of the clinical and laboratory analysis of this rare instance of hereditary pituitary hyperplasia.

DESIGN

The study is a retrospective analysis of three cases from one family.

SETTING

The study was conducted at the National Institutes of Health, a tertiary referral center.

PATIENTS

A mother and both her sons had very early-onset gigantism associated with high levels of serum GH and prolactin.

INTERVENTIONS

The condition was treated by total hypophysectomy.

MAIN OUTCOME MEASURE(S)

We performed clinical, pathological, and molecular evaluations, including evaluation basal and provocative endocrine testing, neuroradiological assessment, and assessment of the pituitary tissue by microscopic evaluation, immunohistochemistry, and electron microscopy.

RESULTS

All three family members had very early onset of gigantism associated with abnormally high serum levels of GH and prolactin. Serum GHRH levels were not elevated in either of the boys. The clinical, radiographic, surgical, and histological findings indicated mammosomatotroph hyperplasia. The pituitary gland of both boys revealed diffuse mammosomatotroph hyperplasia of the entire pituitary gland without evidence of adenoma. Prolactin and GH were secreted by the same cells within the same secretory granules. Western blot and immunohistochemistry demonstrated expression of GHRH in clusters of cells distributed throughout the hyperplastic pituitary of both boys.

CONCLUSIONS

This hereditary condition seems to be a result of embryonic pituitary maldevelopment with retention and expansion of the mammosomatotrophs. The findings suggest that it is caused by paracrine or autocrine pituitary GHRH secretion during pituitary development.

Delayed radiation-induced vasculitic leukoencephalopathy

PURPOSE

Recently, single-fraction, high-dosed focused radiation therapy such as that administered by Gamma Knife radiosurgery has been used increasingly for the treatment of metastatic brain cancer. Radiation therapy to the brain can cause delayed leukoencephalopathy, which carries its own significant morbidity and mortality. While radiosurgery-induced leukoencephalopathy is known to be clinically different from that following fractionated radiation, pathological differences are not well characterized. In this study, we aimed to integrate novel radiographic and histopathologic observations to gain a conceptual understanding of radiosurgery-induced leukoencephalopathy.

METHODS AND MATERIALS

We examined resected tissues of 10 patients treated at Yale New Haven Hospital between January 1, 2009, and June 30, 2010, for brain metastases that had been previously treated with Gamma Knife radiosurgery, who subsequently required surgical management of a symptomatic regrowing lesion. None of the patients showed pathological evidence of tumor recurrence. Clinical and magnetic resonance imaging data for each of the 10 patients were then studied retrospectively.

RESULTS

We provide evidence to show that radiosurgery-induced leukoencephalopathy may present as an advancing process that extends beyond the original high-dose radiation field. Neuropathologic examination of the resected tissue revealed traditionally known leukoencephalopathic changes including demyelination, coagulation necrosis, and vascular sclerosis. Unexpectedly, small and medium-sized vessels revealed transmural T-cell infiltration indicative of active vasculitis.

CONCLUSIONS

We propose that the presence of a vasculitic component in association with radiation-induced leukoencephalopathy may facilitate the progressive nature of the condition. It may also explain the resemblance of delayed leukoencephalopathy with recurring tumor on virtually all imaging modalities used for posttreatment follow-up.

Prospective evaluation of the characteristics and incidence of adenoma-associated dural invasion in Cushing disease

OBJECT

Dural invasion by adrenocorticotropic hormone (ACTH)-secreting adenomas is a significant risk factor for incomplete resection and recurrence in Cushing disease (CD). Since ACTH-producing adenomas are often the smallest of the various types of pituitary tumors at the time of resection, examining their invasion provides the best opportunity to identify the precise sites of early dural invasion by pituitary adenomas. To characterize the incidence and anatomical distribution of dural invasion by ACTH-secreting adenomas, the authors prospectively and systematically analyzed features of dural invasion in patients with CD.

METHODS

The authors prospectively studied consecutive patients with CD undergoing the systematic removal of ACTH-secreting adenoma and histological analysis of the anterior sella dura as well as other sites of dural invasion that were evident at surgery. Clinical, imaging, histological, and operative findings were analyzed.

RESULTS

Eighty-seven patients with CD (58 females and 29 males) were included in the study. Overall, dural invasion by an ACTH-positive adenoma was histologically confirmed in 30 patients (34%). Eighteen patients (60% of dural invasion cases, 21% of all patients) had evidence of cavernous sinus wall invasion (4 of these patients also had other contiguous sites of invasion), and 12 patients (40% of dural invasion cases) had invasion of the sella dura excluding the cavernous sinus wall. Eleven patients (13% all patients) had invasion of the routinely procured anterior sella dura specimen. Preoperative MR imaging revealed an adenoma in 64 patients (74%) but accurately predicted dural invasion in only 4 patients (22%) with cavernous sinus invasion and none of the patients with non-cavernous sinus invasion. Adenomas associated with dural invasion (mean ± SD, 10.9 ± 7.8 mm, range 2-37 mm) were significantly larger than those not associated with dural invasion (5.7 ± 2.1 mm, range 2.5-12 mm; p = 0.0006, Mann-Whitney test).

CONCLUSIONS

Dural invasion by ACTH-producing adenomas preferentially occurs laterally into the wall of the cavernous sinus. Preoperative MR imaging infrequently detects dural invasion, including cavernous sinus invasion. Invasion is directly associated with tumor size. To provide a biochemical cure and avoid recurrence after resection, identification and removal of invaded sella dura, including the medial cavernous sinus wall, are necessary.

Report of selective cortical infarcts in the primate clot model of vasospasm after subarachnoid hemorrhage

BACKGROUND

In human autopsy studies, 70% to 80% of patients with aneurysmal subarachnoid hemorrhage (SAH) showed infarcts in cerebral cortex covered by subarachnoid blood. Thus far, no animal model of SAH is known to produce this peculiar infarct pattern, and its pathogenesis remains enigmatic.

OBJECTIVE

To investigate whether such infarcts occur in the clot model of SAH in primates.

METHODS

We performed a retrospective pathological review of 16 primate brains. In 13 cynomolgus monkeys, a blood clot was placed around the middle cerebral artery after additional removal of the arachnoid membrane from the basal surface of the frontal and temporal cortexes. Three animals underwent sham surgery without placement of a blood clot (controls). The brains were harvested between days 1 and 28 after SAH and examined by a neuropathologist blinded to study group.

RESULTS

We identified 2 types of cortical infarcts. A band of selective cortical laminar necrosis parallel to the cortical surface ("horizontal") was found in 5 animals. The second category of cortical lesions had a "vertical" extension. It included wedge-shaped (n = 2) or pillarlike (n = 2) necrosis. Both horizontal and vertical infarcts were located exclusively in areas adjacent to subarachnoid blood. The presence of a cortical infarct did not correlate with the degree of middle cerebral artery vasospasm (r2 = .24, P = .13).

CONCLUSION

The presence of cortical infarcts suggests that a modified nonhuman primate model of SAH is suitable to examine the pathogenesis of proximal vasospasm and permits investigation of cortical lesions similar to those reported in patients after SAH. Furthermore, it indicates that direct effects of the blood clot on the brain and microcirculation contribute to the development of cortical infarcts after SAH.

Brainstem pathology in spasmodic dysphonia

Spasmodic dysphonia (SD) is a primary focal dystonia of unknown pathophysiology, characterized by involuntary spasms in the laryngeal muscles during speech production. We examined two rare cases of postmortem brainstem tissue from SD patients compared to four controls. In the SD patients, small clusters of inflammation were found in the reticular formation surrounding solitary tract, spinal trigeminal, and ambigual nuclei, inferior olive, and pyramids. Mild neuronal degeneration and depigmentation were observed in the substantia nigra and locus coeruleus. No abnormal protein accumulations and no demyelination or axonal degeneration were found. These neuropathological findings may provide insights into the pathophysiology of SD.

Outcome of using the histological pseudocapsule as a surgical capsule in Cushing disease

OBJECT

Many patients with Cushing disease still have active or recurrent disease after pituitary surgery. The histological pseudocapsule of a pituitary adenoma is a layer of compressed normal anterior lobe that surrounds the adenoma and can be used during surgery to identify and guide removal of the tumor. In this study the authors examined the results of using the pseudocapsule as a surgical capsule in the resection of adenomas in patients with Cushing disease.

METHODS

The authors reviewed a prospective database of data obtained in patients with Cushing disease who underwent surgery. The analysis included all cases in which a lesion was identified during surgery and in which the lesion was believed to be confined to the pituitary gland in patients with Cushing disease between January 1990 and March 2007. Since the objective was to determine the success of using the pseudocapsule as a surgical capsule, patients with invasive tumors and patients in whom no lesion was identified during surgery-challenging cases for surgical success-were excluded from analysis.

RESULTS

In 261 patients an encapsulated adenoma was identified at surgery. Tumor was visible on MR imaging in 135 patients (52%); in 126 patients (48%) MR imaging detected no tumor. The range of tumor size overlapped considerably in the groups with positive and negative MR imaging results, indicating that in addition to size other features of the adenoma influence the results of MR imaging. In 252 patients hypercortisolism resolved after the first operation, whereas in 9 patients (3 with positive MR imaging and 6 with negative MR imaging) early reoperation was required. Hypercortisolism resolved in all 261 patients (256 with hypocortisolism and 5 with eucortisolism) before hospital discharge. Forty-six patients (18%) had postoperative electrolyte abnormalities (30 with hyponatremia and 16 with diabetes insipidus), but only 2 patients required treatment at discharge. The mean clinical follow-up duration was 84 months (range 12-215 months). Six patients (2%) had recurrence of hypercortisolism, all of whom were treated successfully with reoperation.

CONCLUSIONS

Because of their small size, adenomas can be challenging to identify in patients with Cushing disease. Use of the histological pseudocapsule of an adenoma allows accurate identification of the tumor and helps guide its complete excision. With this approach the overall remission rate is high and the rate of complications is low.

An unusual ostensible example of intraoral basal cell carcinoma

An example of oral basal cell carcinoma is presented originating on the posterior mandibular mucosa and gingiva of a 67-year-old female. Histologically, it featured a multifocal pattern. It recurred eight times in a period of 20 years. Tissue samples of the tumor were evaluated with monoclonal antibody Ber-EP4 and were compared with examples of oral mucosa, skin, oral and cutaneous squamous cell carcinoma, peripheral ameloblastoma, ameloblastoma and cutaneous basal cell carcinoma (BCC). Only neoplastic basal cells showed positive immunohistochemical staining. Additionally, microdissected neoplastic areas were evaluated for loss of heterozygosity (LOH) of the PTCH gene with markers D9S303, D9S252 and D9S287. PTCH gene mutations are reported in patients with Gorlin syndrome and sporadic cutaneous BCCs. Loss of one allele was observed with all three markers. Examples of conventional ameloblastomas did not show evidence of LOH. These observations support the inclusion of BCC in the differential diagnosis of appropriate oral mucosal neoplasms.

Application and implementation of selective tissue microdissection and proteomic profiling in neurological disease

OBJECTIVE

Proteins are the primary components of cells and are vital constituents of any living organism. The proteins that make up an organism (proteome) are constantly changing and are intricately linked to neurological disease processes. The study of proteins, or proteomics, is a relatively new but rapidly expanding field with increasing relevance to neurosurgery.

METHODS

We present a review of the state-of-the-art proteomic technology and its applications in central nervous system diseases.

RESULTS

The technique of "selective microdissection" allows an investigator to selectively isolate and study a pathological tissue of interest. By evaluating protein expression in a variety of central nervous system disorders, it is clear that proteins are differentially expressed across disease states, and protein expression changes markedly during disease progression.

CONCLUSION

Understanding the patterns of protein expression in the nervous system has critical implications for the diagnosis and treatment of neurological disease. As gatekeepers in the diagnosis, evaluation, and treatment of central nervous system diseases, it is important for neurosurgeons to develop an appreciation for proteomic techniques and their utility.