Prognostic Implications of Gadolinium Enhancement of Skull Base Chordomas

Low-dose GBCA administration for brain tumour dynamic contrast enhanced MRI: a feasibility study

A key limitation of current dynamic contrast enhanced (DCE) MRI techniques is the requirement for full-dose gadolinium-based contrast agent (GBCA) administration. The purpose of this feasibility study was to develop and assess a new low GBCA dose protocol for deriving high-spatial resolution kinetic parameters from brain DCE-MRI. Nineteen patients with intracranial skull base tumours were prospectively imaged at 1.5 T using a single-injection, fixed-volume low GBCA dose, dual temporal resolution interleaved DCE-MRI acquisition. The accuracy of kinetic parameters (ve, Ktrans, vp) derived using this new low GBCA dose technique was evaluated through both Monte-Carlo simulations (mean percent deviation, PD, of measured from true values) and an in vivo study incorporating comparison with a conventional full-dose GBCA protocol and correlation with histopathological data. The mean PD of data from the interleaved high-temporal-high-spatial resolution approach outperformed use of high-spatial, low temporal resolution datasets alone (p < 0.0001, t-test). Kinetic parameters derived using the low-dose interleaved protocol correlated significantly with parameters derived from a full-dose acquisition (p < 0.001) and demonstrated a significant association with tissue markers of microvessel density (p < 0.05). Our results suggest accurate high-spatial resolution kinetic parameter mapping is feasible with significantly reduced GBCA dose.

Imaging of pituitary tumors: an update with the 5th WHO Classifications-part 2. Neoplasms other than PitNET and tumor-mimicking lesions

Many types of tumors can develop in the pituitary gland. In the recently revised 5th editions of the World Health Organization (WHO) classifications (2021 WHO Classification of Central Nervous System Tumors and the 2022 WHO Classification of Endocrine and Neuroendocrine Tumors), various changes have been made to the tumors other than pituitary neuroendocrine tumor (PitNET)/pituitary adenoma, as well as PitNET. Adamantinomatous craniopharyngioma and papillary craniopharyngioma are now considered separate tumors in the 5th edition of the WHO classification. Tumors positive for thyroid transcription factor 1, a marker of posterior pituitary cells, are now grouped together in the pituicyte tumor family in the 5th edition of the WHO classification of Endocrine and Neuroendocrine Tumors. Poorly differentiated chordoma is newly listed in the 5th edition of the WHO Classification of Endocrine and Neuroendocrine Tumors. In this paper, we present the latest WHO classification of pituitary tumors (adamantinomatous craniopharyngioma, papillary craniopharyngioma, pituitary blastoma, pituicyte tumor family, tumors of pituitary origin other than those of the pituicyte tumor family, germinoma, meningioma, chordoma, metastatic tumors, lymphoma, and pituitary incidentaloma), review diseases requiring differentiation from tumors (pituitary abscess, hypophysitis, pituitary hyperplasia, Rathke's cleft cyst, arachnoid cyst, and aneurysm), and discuss diagnoses based on imaging findings.

Differences in stromal component of chordoma are associated with contrast enhancement in MRI and differential gene expression in RNA sequencing

Chordoma is a malignant bone neoplasm demonstrating notochordal differentiation and it frequently involves axial skeleton. Most of chordomas are conventional type with varying amount of myxoid stroma. Previously known prognostic factors for conventional chordoma are not specific for chordoma: old age, metastasis, tumor extent, and respectability. Here, we aimed to investigate the histologic, radiologic, and transcriptomic differences in conventional chordoma based on the stromal component. A total of 45 patients diagnosed with conventional chordoma were selected between May 2011 and March 2020 from a single institution. Electronic medical records, pathology slides, and pretreatment magnetic resonance imaging (MRI) scans were reviewed. Of the 45 patients, ten cases (4 stroma-rich and 6 stroma-poor tumor) were selected for RNA sequencing, and available cases in the remainder were used for measuring target gene mRNA expression with qPCR for validation. Differential gene expression and gene set analysis were performed. Based on histologic evaluation, there were 25 (55.6%) stroma-rich and 20 (44.4%) stroma-poor cases. No clinical differences were found between the two groups. Radiologically, stroma-rich chordomas showed significant signal enhancement on MRI (72.4% vs 27.6%, p = 0.002). Upregulated genes in stroma-rich chordomas were cartilage-, collagen/extracellular matrix-, and tumor metastasis/progression-associated genes. Contrarily, tumor suppressor genes were downregulated in stroma-rich chordomas. On survival analysis, Kaplan–Meier plot was separated that showed inferior outcome of stroma-rich group, although statistically insignificant. In conclusion, the abundant stromal component of conventional chordoma enhanced well on MRI and possibly contributed to the biological aggressiveness that supported by transcriptomic characteristics. Further extensive investigation regarding radiologic-pathologic-transcriptomic correlation in conventional chordoma in a larger cohort could verify additional clinical significance.

The CT guided transoral approach: A biopsy technique for a poorly differentiated chordoma in a 5 year old

Mass lesions presenting at the craniocervical junction often present a unique challenge due to the complex anatomic arrangement limiting access for tissue diagnosis. The transoral approach has predominantly been used for percutaneous vertebroplasty of high cervical vertebrae with limited literature describing image guided biopsy for bony lesions in this region in the pediatric patient. We describe a technique of computed tomography guided transoral biopsy of a poorly differentiated chordoma located at the C1-C2 level in a 5-year-old child, and review this diagnosis.

Chordoma-Current Understanding and Modern Treatment Paradigms

Chordoma is a low-grade notochordal tumor of the skull base, mobile spine and sacrum which behaves malignantly and confers a poor prognosis despite indolent growth patterns. These tumors often present late in the disease course, tend to encapsulate adjacent neurovascular anatomy, seed resection cavities, recur locally and respond poorly to radiotherapy and conventional chemotherapy, all of which make chordomas challenging to treat. Extent of surgical resection and adequacy of surgical margins are the most important prognostic factors and thus patients with chordoma should be cared for by a highly experienced, multi-disciplinary surgical team in a quaternary center. Ongoing research into the molecular pathophysiology of chordoma has led to the discovery of several pathways that may serve as potential targets for molecular therapy, including a multitude of receptor tyrosine kinases (e.g., platelet-derived growth factor receptor [PDGFR], epidermal growth factor receptor [EGFR]), downstream cascades (e.g., phosphoinositide 3-kinase [PI3K]/protein kinase B [Akt]/mechanistic target of rapamycin [mTOR]), brachyury—a transcription factor expressed ubiquitously in chordoma but not in other tissues—and the fibroblast growth factor [FGF]/mitogen-activated protein kinase kinase [MEK]/extracellular signal-regulated kinase [ERK] pathway. In this review article, the pathophysiology, diagnosis and modern treatment paradigms of chordoma will be discussed with an emphasis on the ongoing research and advances in the field that may lead to improved outcomes for patients with this challenging disease.

Peri-operative prognostic factors for primary skull base chordomas: results from a single-center cohort

BACKGROUND

Skull base chordomas (SBC) are rare malignant tumors and few factors have been found to be reliable markers for clinical decision making and survival prognostication. The aim of the present work was to identify specific prognostic factors potentially useful for the management of SBC patients.

METHODS

A retrospective review of all the patients diagnosed and treated for SBC at the Fondazione IRCCS Istituto Neurologico "Carlo Besta" between January 1992 and December 2017 has been performed. Survival analysis was performed and a logistic regression model was used. Statistically significant predictors were rated based on their log odds in order to preliminarily build a personalized grading scale-the Peri-Operative Chordoma Scale (POCS).

RESULTS

Fifty-nine primary chordoma patients were included. The average follow-up from the first treatment was 82.6 months (95% CI, 65.5-99.7). POCS was built over PFS and MR contrast enhancement (intense vs mild/no, value 4), preoperative motor deficit (yes vs no, value 3), and the development of any postoperative complications (yes vs no, value 2). POCS ranges between 0 and 9, with higher scores being associated with reduced likelihood of survival and progression-free state.

CONCLUSIONS

Our results show that preoperative clinical symptoms (motor deficits), surgical features (extent of tumor resection and surgeon's experience), development of postoperative complications, and KPS decline represent significant prognostic factors. The degree of MR contrast enhancement significantly correlated to both OS and PFS. We also preliminarily developed the POCS as a prognostic grading scale which may help neurosurgeons in the personalized management of patients undergoing potential adjuvant therapies.

Exophytic Lumbar Vertebral Body Mass in an Adult with Back Pain

Chordomas are rare primary bone malignancies derived from notochord remnants. The tumors often are slow-growing and often present with indolent, nonspecific symptoms. Nevertheless, chordomas are locally aggressive and highly prone to local recurrence, necessitating precise planning before biopsy and/or surgical resection. Familiarity with the imaging features of chordomas is, therefore, essential. This case highlights the typical imaging and pathologic features of a spinal chordoma as well as the surgical approach and the patient's subsequent outcome.

MRI Signal Intensity and Electron Ultrastructure Classification Predict the Long-Term Outcome of Skull Base Chordomas

BACKGROUND AND PURPOSE

MR imaging is a useful and widely used evaluation for chordomas. Prior studies have classified chordomas into cell-dense type and matrix-rich type according to the ultrastructural features. However, the relationship between the MR imaging signal intensity and ultrastructural classification is unknown. We hypothesized that MR imaging signal intensity may predict both tumor ultrastructural classification and prognosis.

MATERIALS AND METHODS

Seventy-nine patients with skull base chordomas who underwent 95 operations were included in this retrospective single-center series. Preoperative tumor-to-pons MR imaging signal intensity ratios were calculated and designated as ratio on T1 FLAIR sequence (R_T1), ratio on T2 sequence (R_T2), and ratio on enhanced T1 FLAIR sequence (R_EN), respectively. We assessed the relationships among signal intensity ratios, ultrastructural classification, and survival.

RESULTS

Compared with the matrix-rich type group, the cell-dense type chordomas showed lower R_T2 (cell-dense type: 1.90 ± 0.38; matrix-rich type: 2.61 ± 0.60 P < .001). The model of predicting cell-dense type based on R_T2 had an area under the curve of 0.83 (95% CI, 0.75-0.92). In patients without radiation therapy, both progression-free survival (P = .003) and overall survival (P = .002) were longer in the matrix-rich type group than in the cell-dense type group. R_EN was a risk factor for progression-free survival (hazard ratio = 10.24; 95% CI, 1.73-60.79); R_T2 was a protective factor for overall survival (hazard ratio  = 0.33; 95% CI, 0.12-0.87); and R_EN was a risk factor for overall survival (hazard ratio = 4.76; 95% CI, 1.51-15.01).

CONCLUSIONS

The difference in MR imaging signal intensity in chordomas can be explained by electron microscopic features. Both signal intensity ratios and electron microscopic features may be prognostic factors.

Skull base chordomas review of current treatment paradigms

Background

Chordomas are locally invasive neoplasms, arising from notochordal remnants and can appear anywhere along the axial skeleton. Local recurrences are common, and distant metastases may occur years after the initial presentation.

Methods

Literature review of current treatment strategies for chordomas of the skull base.

Results

Surgery is the mainstay of treatment and complete resection has paramount importance for prognosis.

When complete resection is not achieved recurrent disease is common. The anatomical complexity of the skull base makes resection complex. Endonasal endoscopic approaches to the clivus has become increasingly favored in recent years although addressing reconstruction of the skull base to prevent CSF leak may be challenging.

Evidence suggests that radiotherapy should not be considered as a primary single modality when trying to achieve cure of the disease. Nonetheless, immediate post-operative radiotherapy improves survival. Many strategies have been suggested to preserve sensitive vital structures in the skull base during treatment but as for survival there is no evidence of advantage when comparing adjuvant therapy with photon radiotherapy, gamma knife surgery, proton beam therapy, and carbon ion radiation therapy.

There is no evidence to support cytotoxic chemotherapy in the treatment of chordomas but targeted therapies have started to show promise. Several optional molecular targets exist. Brachyury is overexpressed in 95% of chordomas but not in other mesenchymal neoplasms. However, its precise role in chordoma pathogenesis is currently unclear, and its cellular location in the nucleus makes it difficult to target. The inhibition of brachyury in chordoma cell lines induces growth arrest and apoptosis. This does not have clinical application to date. There are retrospective results with different molecular targeted therapies for advanced chordomas with some effectiveness.

Conclusion

Despite improvements made in the past 10 years in our knowledge of chordoma biology, available therapies still offer a limited benefit. There is an unmet need for new therapeutic options for patients with advanced disease. Therefore, patients with advanced disease should be encouraged to participate in clinical trials when and where available.