Spindle cell oncocytoma with late recurrence and unique neuroimaging characteristics due to recurrent subclinical intratumoral bleeding

Clinicopathological features and endoscopic findings of spindle cell oncocytoma: A case report and review of the literature

INTRODUCTION AND IMPORTANCE

Spindle cell oncocytoma (SCO) of the pituitary gland is very difficult to differentiate from other pituitary neoplasms and is often misdiagnosed based on imaging procedure features. We report a rare case of SCO arising from the neurohypophysis and suggest a useful diagnostic criterion for accurate diagnosis and surgical pitfalls.

CASE PRESENTATION

A 53-year-old man was admitted to our hospital with slight headache and diplopia. Neuroimaging revealed pituitary tumour in the suprasellar and sellar regions with speckled gadolinium enhancement on T1-weighted magnetic resonance imaging, as a so-called blooming artefact. The enhanced anterior pituitary gland was located anteriorly. Computed tomography (CT)-scan demonstrated an isodense mass without calcification showing strong contrast enhancement with iodine contrast medium. Laboratory findings showed no abnormalities. Subtotal resection of the tumour was achieved by an endoscopic endonasal transsphenoidal approach. Histological examinations showed spindle-shaped to epithelioid tumour cells featuring eosinophilic and granular cytoplasm staining strongly for anti-mitochondrial antibody and thyroid transcription factor 1. The tumour was therefore diagnosed as SCO, belonging to tumours of the posterior pituitary. Headache and diplopia were disappeared immediately postoperatively, and follow-up at 12 months demonstrated no signs of recurrence.

CLINICAL DISCUSSION

SCO of the pituitary gland is a rare tumour that originates from the neurohypophysis and is difficult to diagnose on routine neuroimaging procedure.

CONCLUSION

Accurate diagnosis requires careful identification of clinical signs, neuroimaging features including contrast-enhanced CT, and analysis of combined results from morphological and immunohistochemical evaluation of tumour tissue.

Spindle cell oncocytoma of the pituitary tumor: A rare case report and literature reviews

Introduction

Spindle cell oncocytoma (SCO) of the pituitary gland is increasingly established with improvements in histological and immunohistochemical examination. However, the diagnosis was often mistaken based on imaging studies and nonspecific clinical manifestations.

Purpose

This case is presented to provide an overview of the characteristics of the rare tumor as well as to demonstrate the difficulties in diagnosis and current treatments.

Clinical discussion

The pathogenesis of SCO remains unclear, and a possible origin was described. Further research is needed to optimize pre-operative diagnosis and surgical strategy.

Conclusion

SCO should be considered when images indicate some features. Gross total resection (GTR) after surgery seems to have better long-term tumor control, and radiotherapy may help decrease tumor progression in patients with non-GTR. Regular follow-up is advised because of the higher recurrence rate.

Granular Cell Tumor and Spindle Cell Oncocytoma of the Pituitary Gland: Imaging and Intraoperative Cytology Diagnostic Dilemmas and Management Challenges

BACKGROUND

 Tumors arising from the posterior pituitary gland are rare and closely resemble pituitary adenoma in presentation and imaging. Most of them come as a histopathologic surprise. We have analyzed the posterior pituitary tumors managed in our institute and have discussed the dilemmas in imaging, challenges in intraoperative squash cytology, and surgical management.

METHODS

 We retrospectively reviewed our operative database of pituitary tumors over the past 10 years, which included five posterior pituitary tumors (three granular cell tumors [GCTs] and two spindle cell oncocytomas [SCOs]). Clinical, imaging, and endocrine characteristics; intraoperative details; histopathologic features; and postoperative outcomes were collected and analyzed.

RESULTS

 The mean age of the patients was 47 years. All patients presented with varying degrees of vision loss. Radiology revealed a sellar / suprasellar lesion with the pituitary gland seen separately in two of three GCTs, whereas a separate pituitary gland could not be identified in both the SCOs. Pituitary adenoma was a radiologic diagnosis in only two of five cases. Three patients underwent a transsphenoidal surgery, whereas two underwent surgery by the transcranial approach. Intraoperative cytology was challenging, though a possibility of posterior pituitary tumor was considered in three of four cases, whereas one was considered meningioma. All the tumors were very vascular and influenced the extent of resection.

CONCLUSIONS

 GCTs and SCOs are relatively uncommon tumors that are difficult to diagnose on preoperative imaging. Intraoperative squash cytology too can pose challenges. A preoperative suspicion can prepare the surgeon for surgery of these hypervascular tumors. The transcranial approach may be necessary in cases of uncertainty in imaging.

Pituitary spindle cell oncocytoma: illustrative case

BACKGROUND

Spindle cell oncocytoma (SCO) of the pituitary gland is an extremely rare nonfunctional World Health Organization grade I tumor. SCOs are often misdiagnosed as nonfunctional pituitary adenomas on the basis of preoperative imaging. They are often hypervascular and locally adherent, which increases hemorrhage risk and limits resection, leading to increased risk of recurrence. The authors report a case of SCO treated at their institution and provide a review of the current literature.

OBSERVATIONS

SCO of the pituitary gland can be a rare cause of progressively growing pituitary tumors that presents similarly to nonfunctional pituitary adenoma. Endoscopic transsphenoidal resection of the tumor by a multidisciplinary team allowed total resection despite local adherence of the tumor. Postoperatively, the patient’s visual symptoms improved with persistence of secondary adrenal insufficiency and secondary hypothyroidism.

LESSONS

Careful resection is needed due to SCO’s characteristic hypervascularity and strong adherence to minimize local structure damage. Long-term follow-up is recommended due to the tendency for recurrence.

Clinical-Pathological, Immunohistochemical, and Genetic Characterization of a Series of Posterior Pituitary Tumors

Posterior pituitary tumors are supposed to represent the morphological spectrum of a single entity. Herein, we report the clinical-pathological, immunohistochemical, and genetic features of 5 spindle cell oncocytomas (SCOs), 3 pituicytomas, and 1 granular cell tumor (GCT). SCOs had the highest local invasiveness and affected older subjects. The 3 histotypes differed in the content of spindle cells (predominant in pituicytoma and absent in GCT), presence of lymphocytic infiltrate (in SCO and GCT, but not in the pituicytoma) and EMA/GFAP staining (negative in GCT; EMA-positive/GFAP-negative in 4/5 SCO and GFAP-positive in 3/3 pituicytomas). Three SCOs and 1 pituicytoma analyzed with next-generation sequencing had no mutations in 409 genes. However, 1 SCO had previously unreported homozygous deletion of CDKN2A/B and another of SMARCA4, SMARCB1, and NF2. All 3 SCOs had loss of heterozygosity of chromosome 1p, while the pituicytoma had chromosome 19 homozygous loss and chromosomes 10, 13q, and 18q loss of heterozygosity. Since 1p and 13q losses were previously reported in 1 pituicytoma and 1 SCO, respectively, our data demonstrate that posterior pituitary tumors share common genetic alterations. The possibility that posterior pituitary tumors are SMARCA4/SMARCB1-deficient should be kept in mind in the differential diagnosis toward other entities.

Risk factors for tumor recurrence and progression of spindle cell oncocytoma of the pituitary gland: a systematic review and pooled analysis

INTRODUCTION

Spindle cell oncocytoma (SCO) is an extremely rare sellar neoplasm. No observational studies have been reported so far to investigate the prognostic factors of this tumor entity. This systematic review aimed to elucidate the risk factors for tumor recurrence/progression of SCO.

METHODS

We searched for relevant articles in PubMed and Web of Science. Studies providing individual patient data with follow-up information of SCO cases were included. Pearson's Chi square and Fisher's exact test were used for categorical variables while t test or Mann-Whitney tests were applied for continuous variables, if applicable. We used the Cox regression model to assess the effects of suspected variables on progression-free survival (PFS).

RESULTS

A total of 38 case reports and case series comprising of 67 SCOs were included for final analyses. Recurrent/progressive tumors were noted in 38.8% of cases. Among the clinicopathological factors, only the extent of surgery was a significant risk factor for tumor recurrence/progression. SCO patients with a subtotal resection had a significantly higher risk for tumor relapse in comparison with complete removal (HR 7.51; 95% CI 1.75-32.31; p = 0.007).

CONCLUSION

Our study demonstrated the characteristic clinicopathological features of SCOs with a high recurrence/progression rate and outlined the predictor for tumor relapse. Failure to achieve gross total resection is the only risk factor for tumor recurrence/progression.

Posterior pituitary tumours: patient outcomes and determinants of disease recurrence or persistence

OBJECTIVE

Posterior pituitary tumours (PPTs) are rare neoplasms with the four recognised subtypes unified by thyroid transcription factor -1 (TTF-1) expression, according to the 2017 WHO classification. Though traditionally defined as low-grade neoplasms, a substantial proportion of them show recurrence/persistence following surgery.

METHODS

We selected patients with PPTs in our cohort of 1760 patients operated for pituitary tumours over the past 10 years (2010-2019). The clinical, radiological, hormonal, histopathological profiles and long-term outcomes of the three cases identified (two pituicytomas and one spindle cell oncocytoma, SCO) were analysed. Following a literature review, data of all published cases with documented TTF-1 positive pituicytomas and SCOs were analysed to determine the predictors of recurrence/persistence in these tumours.

RESULTS

Patients presented with compressive features or hypogonadism. Two had sellar-suprasellar masses. One had a purely suprasellar mass with a pre-operative radiological suspicion of pituicytoma. Two were operated by transsphenoidal surgery and one transcranially guided by neuronavigation. Histopathology confirmed spindle cells in a storiform arrangement and low Ki67 index. Immunohistochemistry showed positive TTF-1, S-100 expression and variable positivity for EMA, vimentin and GFAP. Re-evaluation showed recurrence/persistence in two patients. A literature review of recurrent/persistent pituicytoma (n = 17) and SCO (n = 9) cases revealed clinical clues (headache for pituicytomas, male gender for SCO), baseline tumour size (≥20.5 mm with sensitivity exceeding 80%) and longer follow-up duration as determinants of recurrence/persistence.

CONCLUSION

PPTs are rare sellar masses with quintessential TTF-1 positivity. Recurrent/persistent disease following surgery is determined by greater tumour size at baseline and duration of follow-up. This warrants intensive and long-term surveillance in these patients.

A Comprehensive Study of Spindle Cell Oncocytoma of the Pituitary Gland: Series of 6 Cases and Meta-Analysis of 85 Cases

OBJECTIVE

To discuss optimal treatment strategy for spindle cell oncocytoma (SCO) of the pituitary gland.

METHODS

Institutional cases were retrospectively reviewed. A systematic literature search and subsequent quantitative synthesis were performed for further analysis. The detailed features were summarized and the tumor control rate (TCR) was calculated.

RESULTS

Eighty-five patients (6 institutional and 79 literature) were included. The annual incidence was approximately 0.01-0.03/100,000. The mean age was 56 years. Vision loss was present in 60%. Seventy-three percent showed hormonal abnormalities. On magnetic resonance imaging, tumor was avidly enhancing, and the normal gland was commonly displaced anterosuperiorly. Evidence of hypervascularity was seen in 77%. Gross total resection (GTR) was achieved in only 24% because of its hypervascular, fibrous, and adhesive nature. The mean postoperative follow-up was 3.3 years for institutional cases and 2.3 years for the integrated cohort. The TCR was significantly better after GTR (5-year TCR, 75%; P = 0.012) and marginally better after non-GTR + upfront radiotherapy (5-year TCR, 76%; P = 0.103) than after non-GTR alone (5-year TCR, 24%). The TCRs for those with low Ki-67 index (≤5%) were marginally better than those with higher Ki-67 index (5-year rate, 57% vs. 23%; P = 0.110).

CONCLUSIONS

Frequent endocrine-related symptoms, hypervascular signs, and anterosuperior displacement of the gland support preoperative diagnosis of SCO. GTR seems to have better long-term tumor control, whereas the fibrous, hypervascular, and adhesive nature of SCO makes it difficult to achieve GTR. In patients with non-GTR, radiotherapy may help decrease tumor progression.

Primary Tumors of the Posterior Pituitary Gland: A Systematic Review of the Literature in Light of the New 2017 World Health Organization Classification of Pituitary Tumors

OBJECTIVE

The rare clinical entity of primary posterior pituitary tumors (PPTs) includes pituicytomas, granular cell tumors, spine cell oncocytomas, and sellar ependymomas. The recent World Health Organization classification of PPTs based on thyroid transcription factor 1 positivity has led to more investigations into the epidemiology, clinical presentation, nature history, histologic features, and operative characteristics of these tumors. The aim of this review is to summarize the characteristics of primary PPTs.

METHODS

Our summary involved an in-depth review of the literature on PPTs. Our systematic review was carried out using the PubMed database and PRISMA guidelines.

RESULTS

An initial search identified 282 publications. After strict application of the inclusion criteria, we found 16 articles for case series of patients with primary PPT (N > 5), which were included in our table for literature review. An additional 10 articles were review articles on PPTs published in the last 20 years and were used as resource for our systematic review. An extensive analysis was then performed to extract relevant clinical data with respect to the clinical radiologic histopathologic profile of primary PPTs and their treatment outcome.

CONCLUSIONS

Primary PPTs are a rare group of pituicyte-derived low-grade nonneuroendocrine neoplasms that arise from the sellar region. The nondescript radiographic findings and subtle endocrine abnormalities also veil their accurate diagnostic prediction. As shown through the narrative as well as the literature review, there is still a lot to be understood about PPTs. A prospective multicenter registry of these rare tumors would benefit both the neurosurgical as well as the endocrinologic knowledge base.

Trans-nasal Trans-sphenoidal Endoscopic Resection of Spindle Cell Oncocytoma of Adenohypophysis: The First Case Report in a Child and a Review of Literature

Spindle cell oncocytoma (SCO) is a rare tumor of adenohypophysis, arising from the sellar region. So far, about 35 cases of SCO in the sellar region have been reported. In this report, we present the first case of pediatric SCO and review the literature concerning the tumor origin, clinical presentations, radiological features, and treatment modalities. An 8-year-old male was referred to our clinic with progressive visual loss in the left eye and headache over the past 6 months. Cranial magnetic resonance imaging revealed a solid adenohypophysis mass with suprasellar extension, as well as compression and displacement of the optic chiasm. The patient underwent endoscopic trans-sphenoidal resection of the tumor. The tumor was diagnosed as SCO based on the histological study. He did not receive radiation therapy. The patient's condition remained stable, with no radiological recurrence in the past follow-up 2 years after the surgery.

Spindle cell oncocytoma of the pituitary gland

OBJECTIVE

The authors report the diagnosis, management, and outcomes of 6 cases of spindle cell oncocytoma (SCO) in an effort to guide clinical diagnosis and management of these uncommon lesions.

METHODS

This study is a retrospective review of cases involving adult patients who underwent resection of pituitary lesions at the authors' institutions between January 2000 and October 2017. The authors identified patients with histopathological confirmation of SCO and collected clinical data, including preoperative, perioperative, and postoperative management, complications, and outcomes.

RESULTS

Six patients with SCO were identified. Clinical findings at initial presentation included visual disturbances, dizziness, and headache. All patients underwent resection. Four resections were initially performed by the transsphenoidal approach, and 2 resections were performed by craniotomy at an outside institution with subsequent transsphenoidal reoperations. Neither necrosis nor increased mitotic activity was seen in the tumor samples. All samples stained positive for S100 protein and thyroid transcription factor 1 and negative for glial fibrillary acidic protein and pituitary hormones. Five of the samples stained positive for epithelial membrane antigen. The average MIB-1 index was 8.3% (range 2-17). Postoperatively, 3 of the 6 patients received further treatment for progression of residual tumor or for recurrence, 2 have stable residual tumor, and 1 has had no recurrence after gross-total resection. Two patients developed postoperative complications of transient sixth cranial nerve palsy and diplopia. There were no other complications.

CONCLUSIONS

SCO poses both a diagnostic and therapeutic challenge. These tumors are often initially misdiagnosed as nonfunctional pituitary adenomas because of their sellar location and nonspecific symptomatology. Postoperatively, SCO must also be distinguished from other neoplasms of the posterior pituitary gland through histopathological examination. Resection of SCO can be challenging, given its highly vascular and adherent nature. Long-term follow-up is critical, as the tumor is associated with higher recurrence and progression rates compared to other benign neoplasms of the sella.

Primary tumors of the posterior pituitary: A systematic review

In 2017, the World Health Organization established that pituicytoma, granular cell tumor (GCT), spindle cell oncocytoma (SCO) and sellar ependymomas (SE) are posterior pituitary tumors (PPT). They probably arise from the pituicytes and may constitute a unique histopathological entity. We carried out a systematic review using PubMed's database. A total of 266 patients with pathological diagnosis of PPT (135 pituicytomas, 69 GCT, 47 SCO, 8 SE and 7 mixed histology tumors) were analyzed. Gender distribution was identical and median age at diagnosis was 48 ± 21.8 years. Main presentation symptoms were visual disorders (n = 142; 58.1%), headache (n = 99; 40.5%), hypopituitarism (n = 84; 34.4%), hypercortisolism (n = 10; 4.1%), polyuriapolydipsia (n = 6; 2.4%) and acromegaly features (n = 5; 2.0%). On MRI, 122 (47.6%) patients showed sellar with suprasellar extension masses, 67 (23.1%) were suprasellar and 63 (24.6%) exclusively sellar. Median tumor size was 22.0 ± 14.2 mm. Two hundred sixty four patients underwent surgery, transphenoidal access was selected in 132 (64.4%) and craniotomy in 58 (28.3%). Complications were hypopituitarism (n = 70; 42.1%), diabetes insipidus (n = 55; 33.1%) and hemorrhage (n = 50; 30.1%). Tumor persisted in 93 patients (45.6%) and recurred in 13 (6.4%). Regarding comparison between main types of PPT, SCO patients were diagnosed later (60.0 vs 47.0 vs 47.0 years, p = 0.023), the tumor was larger 25.0 mm [10.8] vs 20.0 mm [14.2] vs 2.0 mm [15.0] and they were frequently sellar with suprasellar extension tumors (71.7% vs 46.2% vs 32.8%, p = 0.003) compared to pituicytoma and GCT. In conclusion, PPT are rare tumors and have been misdiagnosed mainly as non-functioning pituitary adenomas. Different types of PPT share similar epidemiology, clinical manifestations and surgical outcomes. Surgery is the only curative option but complications and subtotal resection are common.

Posterior pituitary tumours: the spectrum of a unique entity. A clinical and histological study of a large case series

PURPOSE

In 2017, the WHO established that pituicytoma, granular cell tumour (GCT) and spindle cell oncocytoma (SCO) are posterior pituitary tumours (PPT). Recent data suggests that these tumours probably arise from the pituicytes and may constitute a spectrum of a unique histopathological entity. Our aim is to report the clinical findings and surgical outcomes of 16 patients with PPT. We also evaluated the tissue specimens available in light of current knowledge.

METHOD

Cross-sectional study with retrospective data.

RESULTS

PPT were 7 pituicytomas, 3 GCT and 6 SCO. Patients mean age was 55 years old and 75% were female. Basal hormonal study showed hyperprolactinemia (43.7%) and hypopituitarism (37.5%). There was no case of diabetes insipidus (DI). MRI showed sellar/suprasellar masses with mean size of 19.7mm. PPT was not suspected in any patient. Fifteen patients underwent surgery and complications were common: 20% had perioperative bleeding (one patient died because of a massive haemorrhage), 57.1% hypopituitarism, 35.7% permanent DI and 21.4% underwent a second surgery. Pathological findings shown positivity for thyroid transcription factor 1, vimentin and negativity for cytokeratin and chromogranin A in all specimens evaluated. S100 protein was positive in 88.8% of tumours. Ki67 was ≥ 3% in 66.6% and ranged from 4-7% in SCO.

CONCLUSION

PPT have similar histology, clinical features and are frequently misdiagnosed as nonfunctioning pituitary tumours. However, post-surgical complications including haemorrhage are common. A high clinical suspicion is needed to presume the diagnosis prior surgery and diminish the high morbidity of these tumours.

MAPK activation and HRAS mutation identified in pituitary spindle cell oncocytoma

Pituitary spindle cell oncocytoma (SCO) is an uncommon primary pituitary neoplasm that presents with mass effect on adjacent neurovascular structures, similar to non-hormone-producing pituitary adenomas. To determine the molecular etiology of SCO, we performed exome sequencing on four SCO cases, with matched normal controls, to assess somatic mutations and copy number alterations. Our analysis revealed a low mutation rate and a copy-neutral profile, consistent with the low-grade nature of this tumor. However, we identified a co-occurring somatic HRAS (p.Q61R) activating point mutation and MEN1 frameshift mutation (p.L117fs) present in a primary and recurrent tumor from one patient. Other SCOs demonstrated mutations in SND1 and FAT1, which are associated with MAPK pathway activation. Immunohistochemistry across the SCO cohort demonstrated robust MAPK activity in all cases (n=4), as evidenced by strong phospho-ERK staining, while phospho-AKT levels suggested only basal levels of PI3K pathway activation. Taken together, this identifies the MAPK signaling pathway as a novel therapeutic target for spindle cell oncocytoma, which may offer a powerful adjunct for aggressive tumors refractory to surgical resection.

Spindle Cell Oncocytoma of the Anterior Pituitary Presenting with an Acute Clinical Course Due To Intraventricular Hemorrhage. A Case Report and Review of Literature

Patient: Male, 56

Final Diagnosis: Spindle cell oncocytoma of the adenohypophysis

Symptoms: Disturbed conscious level • visual disturbances

Medication: —

Clinical Procedure: Urgent craniotomy

Specialty: Neurosurgery

Spindle cell oncocytoma of the adenohypophysis: two case reports and a review of the literature

Spindle cell oncocytoma (SCO) of the adenohy-pophysis is a rare tumor in the sellar region. Due to its rarity, little information is available regarding SCO. It is often misdiagnosed as another type of sellar tumor. In the present study, two cases of SCO were reported. One patient was a 35-year-old female presenting with decreased visual acuity, amenorrhea and lactation. The other patient was a 62-year-old female with no clear symptoms or signs. Cranial magnetic resonance imaging (MRI) revealed a suprasellar mass with marked homogeneous enhancement in the two cases. A craniotomy was performed to completely resect the tumors. The tumors were immunopositive for vimentin, epithelial membrane antigen (EMA), S-100 and thyroid transcription factor-1 (TTF-1). The tumors were pathologically diagnosed as SCO. No recurrence occurred during the follow-up period of 15–21 months. In the present study, the literature was reviewed and the clinical data, imaging features, intraoperative findings and recurrence of 24 cases were analyzed in the literature as well as the present two cases. The average age of the SCO patients was 58.5 years and no gender preference was observed for the disease. The tumor exhibited homogeneous enhancement on the MRI. The intraoperative assessment revealed that the tumor had a rich blood supply and the SCO tumors were immunopositive for vimentin, S-100, EMA and TTF-1. These findings provided valuable clinical data for the preoperative diagnosis and surgical removal of SCO tumors.

An Algorithmic Approach to Sellar Region Masses

Context

Most sellar region masses (85%–90%) are pituitary adenomas; however, other neoplasms or even inflammatory or cystic nonneoplastic lesions may occasionally be encountered in this location. A practical, non–electron-microscopically based approach is essential for the daily practice of diagnosing and subclassifying adenomatous and nonadenomatous sellar region lesions.

Objective

To provide an algorithmic approach to sellar region masses for the pathologist and to formulate a cost-effective, limited panel of stains and immunostains that can be used in daily practice at most small to medium-sized centers.

Design

Pool collective experience of 3 neuropathologists practicing at academic medical centers with expertise in diagnosis and treatment of sellar region masses to craft a single-page algorithmic diagram and to liberally illustrate the range of lesions present in the sellar region.

Results

After formulating a differential diagnosis, the general pathologist can generate a confident final diagnosis of adenoma using 1 histochemical (reticulin) and 1 immunohistochemical (synaptophysin) stain, supplemented by 5 immunohistochemical stains (CAM5.2, follicle-stimulating hormone, growth hormone, prolactin, and adrenocorticotropic hormone), which provide subtyping of the adenoma in the overwhelming majority of examples. CAM5.2 and clinical information further help identify clinically aggressive variants such as sparsely granulated growth hormone adenomas and silent adrenocorticotropic hormone adenomas, respectively. MIB-1, thyroid transcription factor 1, and S-100 protein can be of further assistance in select cases where increased mitotic activity or possible nonadenomatous spindle cell lesions are suspected.

Conclusions

Adenomas, normal anterior or posterior gland, and nonadenomatous masses can be easily diagnosed in a nontertiary pathology laboratory setting.

Update on hypophysitis and TTF-1 expressing sellar region masses

This article reviews recent literature on sellar region masses that most closely mimic nonsecretory pituitary adenomas: hypophysitis, pituicytoma, spindle cell oncocytoma, and granular cell tumor of neurohypophysis. Even today, these four entities often cannot be confidently distinguished from each other clinically or by preoperative neuroimaging features. Thus, they often come to biopsy/surgical resection and require tissue confirmation of diagnosis. Causes of secondary and primary hypophysitis will be discussed, including two newly described types, IgG4 plasma cell hypophysitis and hypophysitis caused by anti-cytotoxic T-lymphocyte antigen 4 antibody therapy for cancer. For the neoplastic conditions, emphasis will be placed on literature that has emerged since these entities were first codified in the 2007 World Health Organization fascicle. The finding that immunohistochemical staining for thyroid transcription factor-1 is shared by pituicytoma, spindle cell oncocytoma, and granular cell tumor of neurohypophysis suggests common lineage and explains why histological overlap can be encountered. We incorporate our own experiences over the last 30 years from two referral institutions with specialty practices in pituitary region masses.

Rare Tumors of the Sellar Region

Context

The sellar/ parasellar region is the location for a vast array of neoplastic and nonneoplastic intracranial space-occupying lesions. While several common lesions arising in this location have been well-described in the literature, there are rare and challenging tumors that may also arise in this region.

Objective

We focus this review on five rare tumors reported to arise in the sellar region, including spindle cell oncocytoma of the adenohypophysis, pituicytoma, intravascular papillary endothelial hyperplasia, epithelioid hemangioendothelioma and xanthogranuloma. We review their clinical presentation, histologic features, differential diagnosis and outcomes for these tumors.

Data sources

All medical literature pertaining to these entities that was searchable on PubMed was comprehensively reviewed.

Conclusions

Spindle cell oncocytoma and pituicytoma have recently been included in the 2007 edition of the World Health Organization classification of tumours of the CNS, while intravascular papillary endothelial hyperplasia, epithelioid hemangioendothelioma and xanthogranuloma have only rarely been described in this region. Knowledge of these may help prevent possible diagnostic pitfalls during postmortem evaluation.

Rare suprasellar glioblastoma: report of two cases and review of the literature

BACKGROUND AND IMPORTANCE

The suprasellar and hypothalamic/chiasmatic regions can harbor a broad range of pathologic conditions, both neoplastic and nonneoplastic; however, malignant gliomas are extremely rare in those regions.

CLINICAL PRESENTATIONS

Patient 1 was a 70 year-old man with weight loss and rapidly progressive visual impairment. A mass centered in the hypothalamus was detected on magnetic resonance (MR) imaging. The second patient, a 45 year-old woman, complained of visual symptoms and headaches. MR imaging revealed a combined intra- and suprasellar mass. In both instances, the preoperative differential diagnosis favored craniopharyngioma. Histological examination confirmed the diagnosis of glioblastoma.

CONCLUSION

We report two rare adult cases of hypothalamic/chiasmatic glioblastoma. The authors review the literature, highlighting the importance of considering this rare entity in the differential diagnosis of suprasellar and hypothalamic lesions.

Pituicytoma, spindle cell oncocytoma, and granular cell tumor: clarification and meta-analysis of the world literature since 1893

BACKGROUND AND PURPOSE

Pituicytoma, SCO, and GCT are poorly understood entities with confusing nomenclature and undetermined imaging characteristics. Our purpose was to confirm published cases of pituicytoma, SCO, and GCT with the newest 2007 World Health Organization criteria and elucidate imaging findings that distinguish these tumors from common entities such as pituitary adenoma.

MATERIALS AND METHODS

A literature search identified 145 published cases (81 GCTs, 48 pituicytomas, and 16 SCOs). Case diagnoses were blindly reviewed by a neuropathologist according to the latest WHO criteria, resulting in 112 pathologically documented cases (64 GCTs, 35 pituicytomas, and 13 SCOs). Imaging illustrations from proved cases were reviewed to determine location, configuration, attenuation and signal intensity, and enhancement characteristics.

RESULTS

Only pituicytomas presented as purely intrasellar lesions (7/33). Most GCTs were purely suprasellar (28/45). All SCOs were both intra- and suprasellar (13/13). Twenty-five percent of pituicytomas (6/22) and GCTs (7/30) appeared separate from the pituitary gland. All SCOs were infiltrating. Seventy-nine percent of entities appeared isointense to brain on T1-weighted image (34/43). Seventy-four percent of pituicytomas enhanced homogeneously (14/19). Twelve of 23 GCTs and 5/7 SCOs enhanced heterogeneously. Most GCTs were hyperattenuated to brain on CT (18/20). Eleven of 13 cases enhanced homogeneously. Visual disturbances were common symptoms for all entities (67/112). Diabetes insipidus was rare (4/112).

CONCLUSIONS

Pituicytoma may be considered for purely intrasellar masses that are clearly separate from the pituitary gland. GCT should receive consideration for purely suprasellar lesions that are hyperattenuated to brain on CT. SCO should be considered for infiltrating pituitary masses with a mixed intra- and suprasellar location. A history of diabetes insipidus helps to exclude these tumors.

Spindle cell oncocytoma of the pituitary and pituicytoma: Two tumors mimicking pituitary adenoma

BACKGROUND

Spindle cell oncocytoma (SCO) and pituicytoma are rare nonfunctioning tumors of the pituitary. Both tumors are low grade and macroscopically indistinguishable from a nonfunctioning pituitary adenoma.We report one case of SCO and one case of pituicytoma and review the previous literature.

CASE DESCRIPTION

One patient was a 39-year-old man who presented with progressive headache, visual blurring, and polyuria of 3-year duration. He underwent partial resection (30% of the tumor) and postoperative adjuvant radiation therapy. Histopathology revealed SCO. However, after 9 months, the residual tumor grew and partial resection (70% of the tumor) was performed again. Four months after the second surgery, the tumor recurred again and he underwent transsphenoidal resection of the tumor with stable residual tumor to date. The other patient was a 59-year-old man who presented with a 3-month history of visual decline, fatigue, difficulty in writing, and polyuria. He underwent transsphenoidal resection (total) of the tumor. Histopathology revealed pituicytoma. He has been stable without evidence of recurrence for 1 year and 4 months.

CONCLUSION

To date, there are 15 reported cases of SCO and 45 reported cases of pituicytoma including our cases. An incomplete resection of the tumor was a significant risk factor for recurrence in both SCO and pituicytoma (P = 0.0014 and P = 0.019, respectively). These tumors have a tendency to be hypervascular, which may hamper total resection. Epithelial membrane antigen (EMA) and mitochondria positivity is characteristic to SCO and they are considered to be important immunomarkers to distinguish these tumors.

The new World Health Organization Classification of Central Nervous System Tumors: what can the neuroradiologist really say?

The WHO Classification of Tumors of the Central Nervous System has become the worldwide standard for classifying and grading brain neoplasms. The most recent edition (WHO 2007) introduced a number of significant changes that include both additions and redefinitions or clarifications of existing entities. Eight new neoplasms and 4 new variants were introduced. This article reviews these entities, summarizing both their histology and imaging appearance. Now with more than 3 years of clinical experience following publication of the newest revision, we also ask, "What can the neuroradiologist really say?" Are there imaging findings that could suggest the preoperative diagnosis of a new tumor entity or variant?