A Rare Case of Pituicytoma Presenting Cystic Formation

Pituicytoma is a rare solid benign tumor of the sellar and/or suprasellar region originating from the pituicytes of the neurohypophysis or infundibulum, which is not differentiated from a pituitary adenoma that is diagnosed mostly in the sellar and/or suprasellar region. In addition, cystic tumors are very rare and have not been reported due to their solid and hypervascular natures. A 33-year-old man presented with a chronic headache which exacerbated recently. MRI was performed and revealed a cystic tumor in the sellar and suprasellar regions with a small parenchymal island in the cyst compressing the optic chiasm. The endoscopic endonasal transsphenoidal approach was used to remove the tumor. Immunohistochemical staining was positive for thyroid transcription factor 1, S-100 protein, and glial fibrillary acidic protein. The pituicytoma was diagnosed based on histologic findings. The authors review herein the literature on clinical presentation, diagnosis, surgical management, and outcome.

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.

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.

Granular Cell Pituitary Tumor in a Patient with Multiple Endocrine Neoplasia-1

Multiple endocrine neoplasia type 1 (MEN-1) is an autosomal dominant disorder characterized by parathyroid, pancreatic islet, and pituitary tumors. Approximately 40% of MEN-1 patients harbor a pituitary adenoma. Separately, granular cell tumors (GCTs) of the sellar/parasellar region are an exceedingly rare clinical entity with less than 100 reported cases in the literature. These slow-growing, often asymptomatic lesions are difficult to diagnose and may mimic pituitary adenoma, Rathke cleft cyst, or other sellar/supra-sellar pathology. There is no known association with MEN-1 or any other familial syndrome. A 36-year-old neurologically normal woman with known MEN-1 underwent a screening magnetic resonance imaging (MRI) scan which revealed a 10 mm x 6 mm x 7 mm sellar/suprasellar lesion. She underwent endoscopic endonasal transsphenoidal resection. Subsequent neuropathological analysis was consistent with GCT of the pituitary gland. Here we describe the first report to our knowledge of a GCT of the pituitary gland occurring in a patient with MEN-1.

Clinical features, diagnosis and therapy of pituicytoma: an update

BACKGROUND

Pituicytomas (PTs) are extremely rare, low-grade glial tumors closely related to the neurohypophyseal axis. Definite conclusions concerning the optimal diagnostic and therapeutic approach to these neoplasms are lacking to date, as most of this information has been presented as case reports.

METHODS

Retrospective review of case reports published in the scientific literature to date, including a new illustrative example treated in our department.

RESULTS

116 cases were collected. PTs had a higher prevalence in the fifth and sixth decades of life, with a slight male predominance. Main symptoms, which tended to be progressive, included visual field defects and pituitary-hypothalamic dysfunction. Radiologically, PTs were found anywhere along the hypothalamic-pituitary axis mimicking other, more frequent tumors growing in this anatomical region. Surgical treatment included both transcranial or transsphenoidal approaches, and resulted in gross total resection and morbidity rates of 46.8 and 59%, respectively; the latter essentially consisted in anterior and posterior pituitary dysfunction, with limited impact on daily quality of life.

CONCLUSIONS

Due to both low frequency and the absence of pathognomonic clinical and/or radiological features, formulating a suspicion diagnosis of PT represents a considerable challenge even for experienced professionals. The indication for treatment should be made on an individual basis, but it is inescapable in the presence of a visual field defect. The surgical approach has to be tailored according to the topography of the tumor and preoperative symptoms; the greatest challenges in accomplishing a gross total removal are represented by the degree of adherence and vascularization of the PT.

Management of pituicytomas: a multicenter series of eight cases

PURPOSE

Pituicytomas and spindle cell oncocytomas (SCOs) are two rare neoplasms of the sellar and suprasellar region, known to be challenging as they are extremely vascular and almost always misdiagnosed, altering our surgical planning and the patients' outcomes. Also we argue that recent update concerning the pathology findings of these tumors should be more widely generalized to our practice.

METHODS

This is a retrospective multicenter study, reporting the clinical manifestations, radiological characteristics, histopathological features, treatment strategies and long-term outcomes of patients who have been treated for a Pituicytoma at various institutions in Paris, France over the past 10 years. In addition, we compared our results to the world literature in order to identify similarities concerning the radiographic diagnosis and the treatment strategies of these tumors.

RESULTS

Eight patients were operated on in four different hospitals. Misdiagnosis was constant before surgery, pituitary adenoma or craniopharyngioma being suspected. During surgery (transsphenoidal approach: six cases, transcranial approach: two cases) unusual tumors were noted, with important bleeding in most cases. Complete resection could be obtained in five patients. Pathological diagnosis was confirmed in all cases. During the follow up two recurrences occurred. One was subsequently treated with radiotherapy, the other underwent a second surgery.

CONCLUSION

Recent updates concerning the histological diagnosis of pituicytomas should be generalized to our practice in order to provide a better understanding of this rare pathology and its natural course.

Epithelioid pituicytoma: An unusual case report

Background:

Pituicytomas are considered World Health Organization Grade I malignancies. Until September 2017, a total of 81 cases of pituicytomas were diagnosed and described in literature. We present such a case in which histopathology shows an epithelioid pattern, a rare variant of pituicytoma. As far as we know, this is only the second such case described in the literature.

Case Description:

A 61-year-old male patient presented with complaints of progressive decrease in visual acuity for about 7 months, worse on the left side. Laboratory and endocrinological investigation returned normal values. Magnetic resonance imaging revealed a mixed solid-cystic lesion, measuring about 3.1 × 2.2 × 2.9 cm. The lesion presented with intermediate signal intensity in T1 and T2 sequences and showed avid postcontrast enhancement. The patient underwent resection through a left pterional approach. Pathology revealed a glial neoplasm with an epithelioid pattern and moderate cellularity with rounded-elongated cell nuclei and with a broad eosinophilic cytoplasm. Absence of cellular pleomorphism, any mitotic figures, or areas of necrosis was noted.

Conclusion:

The epithelioid variant of pituicytomas differs from the commonly encountered forms of this tumor which typically present in a fascicular pattern. Microsurgical resection is the treatment of choice. However, in many cases, subtotal resection was performed because of a considerable risk for neurovascular injuries.

An exceptional presentation of pituicytoma apoplexy: A case report

Pituicytomas are a rare form of indolent neoplasms, which typically present with visual disturbance and hypopituitarism. Complete resection by a trans-sphenoidal approach is the optimal treatment. Only 80 cases have been described thus far in the current literature and the present case is the first to describe the development of pituitary apoplexy in the context of a pituicytoma. A 77-year-old man presented with fatigue and clinical signs of hypogonadism and a sellar lesion was diagnosed at cerebral magnetic resonance imaging (MRI). A watch-and-wait management was initially decided and 1 year after the initial diagnosis, he presented with a thunderclap headache with images suggestive of pituitary apoplexy. A pituitary adenoma was suspected and an endoscopic resection was decided upon the development of a visual deficit. Pathological analysis established the correct diagnosis of a pituicytoma. Pituicytomas are characterised by dense vascularisation, thus ischaemic and haemorrhagic events may be common. When confronted with a hypervascularised pituitary lesion demonstrating strong contrast enhancement and no abnormal hormonal secretion, one must maintain a high index of suspicion for a pituicytoma. A wide range of differential diagnoses should thus be considered in the context of pituitary apoplexy.

Pituicytoma with Significant Tumor Vascularity Mimicking Pituitary Macroadenoma

A 19-year-old man presented with bitemporal hemianopsia and was found to have a large sellar and suprasellar tumor, resembling a pituitary macroadenoma. Emergency transsphenoidal approach was attempted because of rapid visual deterioration with headache. However, the approach was complicated and stopped by uncontrolled hemorrhage from the tumor. After conventional cerebral angiography and recognition of an unusual pathology, transcranial approach was achieved to prevent permanent visual loss. The final pathological diagnosis was pituicytoma with epithelioid features. Pituicytoma is a rare low-grade tumor (WHO Grade I) of pituicytes involving the sellar and suprasellar region, and originating from special glial cells of the neurohypophysis. Because of the high vascularity, the firm consistency, and invasion to surrounding neurovascular structures, a pituicytoma should be included in the differential diagnosis of a mass in the sellar and suprasellar area if the tumor shows high enhancement with vascular components. We report a case of rare pituicytoma mimicking a pituitary macroadenoma with massive hemorrhage to disturb surgery.

First Depiction of Flow Voids to Differentiate Pituicytomas from Giant Adenomas

Pituicytomas are rare low-grade glial lesions of neurohypophysis or adenohypophysis. They are often misdiagnosed as adenomas due to their similar morphology. Previous reports have underlined their nonspecific aspect. In our experience, presence of flow voids on magnetic resonance, which usually indicate hypervascularized tumors with strong arterial supply, may be a useful sign to identify pituicytomas. Unlike adenomas, pituicytomas are highly vascularized tumors. Second, we emphasize the strong enhancement of these tumors when compared with normal hypophysis, which may be another sign of their hypervascularization. Indeed, adenomas, on the opposite side, present less enhancement than normal hypophysis. This observation is corroborated by previous histologic studies that showed adenomas present less vascular density than normal pituitary glands. However, in large tumors, the normal hypophysis can sometimes not be individualized and thus the enhancement gradient between the tumor and normal tissue cannot be properly assessed. Due to their rarity, no previous reports had ever emphasized the specific signs that could allow us to differentiate pituicytomas from adenomas; however, it seems crucial due to the potential hemorrhagic complications of pituicytoma surgery.

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

The clinicopathological features of pituicytoma and the differential diagnosis of sellar glioma

Pituicytoma is rare and difficult to diagnose. This study explored the clinicopathological features, immunophenotype and differential diagnosis of pituicytoma. We compared 11 cases of pituicytoma and 26 cases of sellar glioma (16 pilocytic astrocytomas, four diffuse astrocytomas, three pilomyxoid astrocytomas, and three third ventricle chordoid gliomas). The 11 pituicytoma cases involved six men and five women (age: 33-65 years). Three of the 11 patients experienced recurrence due to a residual tumor, and one patient underwent three surgeries during a 6-month period. Imaging findings revealed tumors were in the intrasellar region (four cases), suprasellar region (four cases) and intra-suprasellar regions (three cases). The tumor diameters were 1.3-3.8 cm, and the preoperative diagnoses were pituitary adenoma, craniopharyngioma and meningioma. The tumors were solid and contained spindle or slightly chubby cells that were densely arranged with visible cleft-like or expanded sinusoid structures. The cells had vague boundaries, circular nuclei, fine chromatin, and a small nucleolus. Immunohistochemical staining of the pituicytomas revealed positive expression of thyroid transcription factor-1 (TTF-1) and S-100 protein (S-100), positive focal expression of glial GFAP;(five of 11 cases), and negative oligodendrocyte transcription factor 2 (Olig2), CD34 and neurofilament expression. The Ki67 index was 6% in one case and 1-2% in the other cases. Unlike pituicytoma, most sellar glioma cases exhibited GFAP and Olig2 expression, and negative TTF-1 expression. Third ventricle chordoid gliomas expressed TTF-1, GFAP and CD34, and were negative for Olig2. Our results indicate that pituicytoma typically involves dense arrangements of spindle or slightly chubby cells. The morphology is occasionally atypical, with ependymoma-like or meningioma-like structures, and occasionally exhibits pilomyxoid degeneration. Abundant sinusoids are characteristic of hemorrhagic tumors. The dense spindle cell arrangement is a relatively specific morphology, and staining for GFAP, TTF-1, Olig2 and CD4 may help differentiate pituicytoma from sellar glioma.

Second-stage transsphenoidal approach (TSA) for highly vascular pituicytomas in children

INTRODUCTION

A pituicytoma in the sellar area is extremely rare in children and, due to its highly vascularized nature, can be difficult to address using the transsphenoid approach (TSA) to surgery. Here, we report a rare case of a pituicytoma that was completely removed from a child through a staged operation using the TSA. A 13-year-old girl was admitted with a 1-year history of visual disturbance and amenorrhea. Visual field examination showed left total blindness and right temporal hemianopsia. Laboratory results revealed hormonal levels all within normal ranges. Brain magnetic resonance imaging (MRI) showed a homogeneous, highly enhancing sellar and suprasellar mass, typically suggestive of a pituitary adenoma. TSA surgery revealed the tumor had a rubbery-firm consistency, hypervascularity, and profuse bleeding. We removed the tumor partially and planned a second-stage operation.

DISCUSSION

Gross total removal is the treatment of choice for this type of tumor. Attempted resection of these presumed adenomas or meningiomas using the TSA often results in unexpectedly heavy intraoperative bleeding due to the high vascularity of this rare tumor, making surgery challenging, especially in children where the tumor is within a relatively narrow corridor. While pituicytomas are a rare differential diagnosis for sellar or parasellar tumors in children, total removal by second-stage TSA surgery is indicated in the case of profuse bleeding or uncertainty of biopsy. Following first-stage TSA surgery and pathologic confirmation of pituicytoma, the strategy is typically gross total removal during second-stage TSA surgery.

CONCLUSIONS

Although very rare in children, a pituicytoma should be included in the differential diagnosis of a mass in the sellar area if the tumor is highly enhancing or very vascular. Second-stage TSA surgery is another strategy when the pathology is not clear during the first-stage TSA surgery.

Pituicytomas and spindle cell oncocytomas: modern case series from the University of California, San Francisco

PURPOSE

Pituicytomas and spindle cell oncocytomas (SCOs) are extremely rare neoplasms of the sellar and suprasellar region that can often mimic pituitary adenomas. To date, there are relatively few cases of pituicytomas and SCOs reported; and most of these are small case series.

METHODS

In this paper, we provide a retrospective review of the treatment, imaging characteristics, post-operative course, and histopathology of five cases of pituicytomas and two SCOs treated at the University of California, San Francisco (UCSF) over a 10-year period from 2003 to 2013.

RESULTS

We find that pituicytomas and SCOs present similarly to pituitary adenomas, and look identical on CT or MR imaging. We histopathologically confirmed all pituicytomas with a combination of hematoxylin and eosin morphology and immunohistochemical positivity for vimentin and S100; SCOs stain for anti-mitochondrial antigen and endothelial membrane antigen. We observe positive thyroid transcription factor 1 (TTF1) immunohistochemistry in both cases of SCO, as well as in both of the cases of pituicytoma in which TTF1 staining was available.

CONCLUSIONS

This represents the largest single-institution case series of pituicytomas and SCOs to date, and also includes the first description of the management of a pregnant female with SCO. Our findings are consistent with the idea of common histogenesis for pituicytomas and SCOs, and also raise the possibility of more aggressive growth in SCOs as compared to pituicytomas.

Surgical management of pituicytomas: case series and comprehensive literature review

OBJECTIVE

Pituicytomas are rare neoplasms that typically present as solid, noninfiltrative tumors occupying the sella and/or suprasellar space for which there is no consensus on optimal surgical management. We aimed to define a preferred surgical strategy for these tumors based on our clinical experience and comprehensive review of the world literature.

DESIGN

Case series and review of the literature.

METHODS

We documented the clinical, radiographic, and surgical findings of three patients with pituicytoma treated at our institution, as well as complications and long-term outcomes. A comprehensive review of the medical literature identified all cases of pituicytoma for which data regarding surgical approach, outcome and complications could be extracted. We compared our results with published data.

RESULTS

All three cases at our institution achieved gross total removal. Two patients underwent an expanded endoscopic endonasal transsphenoidal and transplanum (EETS-TP) approach, while one tumor was removed via craniotomy. Post-operatively all patients developed pan-hypopitutarism. The patient undergoing craniotomy suffered profound visual loss but no other neurological complications were noted. A literature review identified 67 reported cases of pituicytoma. Surgical data was available in 60 cases. Surgical approach was documented in 57 patients. Sixty-three surgeries were performed in which approach and extent of resection was available. Gross total removal was obtained in 33 % of craniotomies, 42 % of transsphenoidal procedures, and 100 % of expanded transsphenoidal procedures. Neurological complications including visual loss, hemiparesis and cranial nerve palsies were reported after craniotomy, but not after transsphenoidal approaches. Overall EETS-TP approaches were associated with the highest rate of gross total removal and no visual or neurological complications.

CONCLUSIONS

EETS-TP surgery is the preferred strategy for surgical removal of pituicytoma. EETS-TP and transsphenoidal approaches are associated with higher rates of gross total removal and lower rates of neurological complications than craniotomy. Gross total removal should be the intended goal of surgery.

Pituicytoma with gelsolin amyloid deposition

Pituicytoma is a rare low-grade (WHO grade I) sellar region glioma. Among sellar tumors, pituitary adenomas, mainly prolactinomas, may show amyloid deposits. Gelsolin is a ubiquitous calcium-dependent protein that regulates actin filament dynamics. Two known gene point mutations result in gelsolin amyloid deposition, a characteristic feature of a rare type of familial amyloid polyneuropathy (FAP), the Finnish-type FAP, or hereditary gelsolin amyloidosis (HGA). HGA is an autosomal-dominant systemic amyloidosis, characterized by slowly progressive neurological deterioration with corneal lattice dystrophy, cranial neuropathy, and cutis laxa. A unique case of pituicytoma with marked gelsolin amyloid deposition in a 67-year-old Chinese woman is described. MRI revealed a 2.6-cm well-circumscribed, uniformly contrast-enhancing solid sellar mass with suprasellar extension. Histologically, the lesion was characterized by solid sheets and fascicles of spindle cells with slightly fibrillary cytoplasm and oval nuclei with pinpoint nucleoli. Surrounding brain parenchyma showed marked reactive piloid gliosis. Remarkably, conspicuous amyloid deposits were identified as pink homogeneous spherules on light microscopy that showed apple-green birefringence on Congo red with polarization. Mass spectrometric-based proteomic analysis identified the amyloid as gelsolin type. Immunohistochemically, diffuse reactivity to S100 protein and TTF1, focal reactivity for GFAP, and no reactivity to EMA, synaptophysin, and chromogranin were observed. HGA-related mutations were not identified in the tumor. No recurrence was noted 14 months after surgery. To the knowledge of the authors, amyloid deposition in pituicytoma or tumor-associated gelsolin amyloidosis has not been previously described. This novel finding expands the spectrum of sellar tumors that may be associated with amyloid deposition.

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 infundibular tumors: clinical presentation, imaging findings, and the role of endoscopic endonasal surgery in their management

Background The spectrum of infundibular lesions is broad and distinct from sellar pathologies. In many cases, histology is needed to establish the correct diagnosis and determine the treatment approach. Methods Medical files of eight patients with distinct infundibular tumors were reviewed. Histopathologically confirmed diagnosis included three pituicytomas, three granular cell tumors, and two pilocytic astrocytomas. Results Patients shared similar imaging findings and clinical symptoms, including visual impairment (n = 5), hypopituitarism (n = 4), and headache (n = 4); one patient presented with disseminated disease and symptoms from spinal metastases. All the pituicytomas, two granular cell tumors, and one infundibular pilocytic astrocytoma case underwent endoscopic endonasal surgery; gross total resection was achieved in five patients, three developed postoperative diabetes insipidus, and two developed hypopituitarism. No recurrences were observed. One granular cell tumor patient was treated with gamma-knife radiosurgery after stereotactic biopsy; the tumor remained stable in size for over 9 years. The infundibular pilocytic astrocytoma patient who presented with spinal metastases received radiotherapy and systemic chemotherapy. The overall mean follow-up period was 25.1 months. Conclusion Infundibular tumors are rare entities that represent a diagnostic challenge. Histopathological examination is essential for definitive diagnosis. Surgery, radiation therapy, and chemotherapy all have a role in the management of these tumors.

Pituicytoma in a patient with Cushing's disease: case report and review of the literature

Pituicytoma is an exceptionally rare low-grade glioma (WHO grade I) of the neurohypophysis and infundibulum. We are reporting the case of a 48-year-old man who presented with severe Cushing's syndrome. Endocrinological evaluation unequivocally confirmed pituitary-dependent Cushing's syndrome (=Cushing's disease). Cranial MR-imaging displayed a conspicuous area in the dorsal and basal pituitary gland and a minimal bulging of the pituitary gland paramedian of the pituitary stalk on the right side. Transsphenoidal inspection revealed a small tumor in the basal and dorsal pituitary gland. Surprisingly, the definite postoperative histopathological diagnosis of the removed tumor was pituicytoma and not pituitary adenoma. Hence, the microadenoma responsible for Cushing's disease was not yet removed and persistent hypercortisolism necessitated transsphenoidal re-operation. During re-operation, hemihypophysectomy was performed on the right side. The non-tumorous specimen of the adeno-hypophysis showed signs of Crooke's hyalinization consistent with Cushing's disease. Undetectable postoperative ACTH- and cortisol levels provided clear evidence that the underlying ACTH-source was successfully removed during re-operation. Coincidence of pituicytoma and pituitary-dependent Cushing's disease has not previously been reported.

Neuroimaging characteristics and growth pattern on magnetic resonance imaging in a 52-year-old man presenting with pituicytoma: a case report

INTRODUCTION

Pituicytoma is a rare neoplasm of the neurohypophysis. To the best of our knowledge there have been no reports of pituicytoma in which long-term magnetic resonance imaging observation was performed. We calculated the doubling time of the tumor volume and described the growth pattern of a pituicytoma.

CASE PRESENTATION

A 52-year-old Japanese man with a history of decreased libido was found to have a sellar and suprasellar mass. He underwent transsphenoidal surgery, but only a small specimen was obtained because of intraoperative bleeding. The tentative histological diagnosis was schwannoma. He noticed bitemporal hemianopsia 7 years later. A follow-up magnetic resonance imaging disclosed a tumor volume doubling time of 3830 days. Transcranial gross-total tumor resection was performed. The lesion consisted of elongated and plump tumor cells that were arranged in a fascicular or storiform pattern and were positive for S-100 protein and focally positive for glial fibrillary acidic protein. The final histological diagnosis was pituicytoma.

CONCLUSION

Pituicytoma is a slow-growing tumor, but the growth rate may change during follow-up.

[Pituitary pituicytoma]

Pituicytomas are rare entities which develop in the neurohypophysis. They were included in the last World Health Organization (WHO) Classification of Central Nervous System Tumours in 2007, but for many years they have been confused with other pituitary tumours. We report the case of a 31-year-old woman who was diagnosed of a tumour in the suprasellar region during an infertility study due to hypogonadotropic hypogonadism and slight hyperprolactinemia. A standard pterional approach was performed, achieving total tumour excision. After the surgery the patient suffered bitemporal hemianopsia, diabetes insipidus and panhypopituitarism, although she recovered from the latter 2 in a few weeks. We conducted a review of the most common clinical and radiological features of this entity, as well as the treatments proposed in the literature to treat this rare tumour.

Pituicytoma: overview of treatment strategies and outcome

The pituicytoma is an extremely rare and little-studied primary tumour of the adult neurohypophysis. With total resection, the pituicytoma appears to have a good prognosis. However, its highly vascular nature makes total resection difficult and local recurrence after subtotal resection is not uncommon. To date, only 40 cases of pituicytoma have been reported in literature. In addition to our own case of a suprasellar pituicytoma, we are reviewing and discussing these with particular attention paid on the surgical management and outcome of this rare neoplasm.

Pituicytomas: radiological findings, clinical behavior and surgical management

BACKGROUND

Pituicytomas are rare low-grade glial neoplasms originating in the neurohypophysis or infundibulum that appear as solid, noninfiltrative masses occupying the sella turcica, the suprasellar space or both. Due to their high tendency to bleed and the possible firmness and adhesion to surrounding structures, preoperative diagnosis of pituicytoma is a goal for the surgeon, but it is actually a challenge because of the absence of distinctive clinical or neuroradiological findings.

METHODS

We report the new cases of three patients who underwent transsphenoidal surgery for suspected pituitary adenomas, which were determined to be pituicytomas at histological and immunohistochemical analysis. We also review previously reported cases of pituicytoma in the literature.

RESULTS

To date, 51 cases of pituicytoma have been reported in addition to our own cases. The natural history and clinical characteristics of this rare tumor are outlined.

CONCLUSIONS

Macroscopic aspects are variable, and final diagnosis is made from the typical histological and immunohistochemical pattern. The therapy of choice is gross total surgical resection since subtotal removal can lead to local regrowth, but the time to recurrence is unpredictable and highly variable. The role of adjuvant therapy is currently undefined.

Epithelioid pituicytoma

BACKGROUND

Pituicytomas are rare tumors of the sellar region that are derived from specialized glial cells called pituicytes. They characteristically exhibit spindle-cell features and fascicular or storiform patterns of growth. No other histological variants of this tumor have been described.

CASE DESCRIPTION

Here we report a diagnostically challenging case of pituicytoma in a 42-year-old man with a sellar mass arising from the pituitary stalk. On histological examination, the tumor displayed an epithelioid histoarchitecture with no characteristic spindle-cell or fascicular growth features. Strong immunopositivity for the pituicyte marker thyroid transcription factor-1 within tumor cells proved essential for diagnosing this unusual pituicytoma variant.

CONCLUSION

Pituicytomas may display epithelioid rather than fascicular or storiform histoarchitecture. Epithelioid pituicytoma variants may be diagnosed in cases such as ours in which both the clinical findings and immunohistochemical analysis suggest a tumor derived from pituicytes.

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.

Pituicytoma: case report and literature review

Pituicytoma is a rare primary tumour of the neurohypophysis or infundibulum, which masquerades as a pituitary adenoma. We present a pituicytoma case in a 45-year-old female presenting as a focal lesion of the neurohypophysis. This case report reviews the clinical, neuroimaging and histopathological features of this rare tumour in order to understand it better.

Pituicytoma

Background:

Pituicytomas originate from pituicytes, modified glial cells derived from ependymal lineage that are found in the stalk and posterior lobe of pituitary gland. The clinical presentation is similar to other pituitary tumors and imaging exams may suggest pituitary adenoma. The diagnostic is based on histopathological analysis. Surgical treatment can be performed by transsphenoidal approach with good results. The prognostic is good after total tumor resection.

Case Description:

We describe here the case of a 17-year-old patient with a history of persistent headache and visual disturbances. Magnetic resonance imaging demonstrated an enhancing solid sellar mass suggestive of pituitary adenoma. The intrasellar mass was resected through a transsphenoidal approach and the diagnosis of pituicytoma was made after histopathological analysis.

Conclusion:

Pituicytomas are rare tumors of the neurohypophysis derived from pituicytes. Their clinical presentation resembles that of non-functional pituitary adenomas, but these two types of tumors are histologically well distinct.

Pituicytoma: Report of two cases

This report describes two cases of pituicytoma. The two patients were female and presented with visual complaints, diabetes insipidus, headaches and menstrual disorders. The imaging characteristic was an intrasellar or suprasellar mass, and one mass originated in the pituitary stalk. The mass showed homogeneous enhancement with contrast administration. A hematoxylin and eosin stain showed a compact structure consisting of elongated, bipolar spindle cells arranged in interlacing fascicles or assuming a storiform pattern. Immunohistochemically, the tumor showed diffuse strong expression of S-100 protein, vimentin and epithelial membrane antigen, and glial fibrillary acidic protein was focally positive. The pituicytoma may have originated in the pituitary stalk and presented with diabetes insipidus, and the differential diagnosis should be compared with the pituitary stalk mass. Bleeding during resection was moderate, and surgery was regarded as the first choice of treatment for pituicytomas.

Diagnostic and clinical implications of pituicytoma

Pituicytoma is a rare, indolent, benign tumor of the sellar and suprasellar region arising from pituicytes of the neurohypophysis. It is most often diagnosed pre-operatively as a pituitary adenoma. We report two patients with pituicytoma operated on at our Institute over 8 years. Imaging of one patient showed a parasellar and medial temporal extension, which has not been reported to our knowledge. The radiological features that help distinguish this low-grade tumor from other sellar and parasellar tumors are discussed along with its distinct histological findings. The authors also review the literature on its clinical presentation, diagnosis, surgical management and outcome.