Pituicytoma incidentally found at autopsy

Surgical approach to the treatment of pituicytoma. Report of five cases and a literature review

Background

Pituicytoma (PTs) is a rare tumor of the sella and suprasellar region, derived from the pituicytes of the neurohypophysis, having distinct histological characteristics of glial neoplasms. We reported, the clinical data, neuroimaging studies, surgical approaches and pathology in five patients with PTs and also, we reviewed the literature.

Methods

Retrospective chart from five consecutive patients with PTs treated at one University Hospital from 2016 to 2021 were reviewed. In addition, we conducted a search in PubMed/Medline databases using the term "Pituicytoma". Data regarding age, gender, pathological findings, and treatment modality applied were extracted.

Results

All patients were female, aged 29-63, complaining of headaches, visual loss and field defects, dizziness and normal or abnormal levels of circulating pituitary hormones. Magnetic Resonance Imaging (MRI) showed in all patients a sellar and suprasellar mass, which was removed through an endoscopic transsphenoidal approach. Our third patient had a subtotal resection followed by close observation. Histopathology showed a glial non-infiltrative tumors with spindle cells, and a final diagnosis of pituicytoma was made. After surgery, visual field defects in all patients were normalized, and in two patients normal levels of plasma hormones were restored. After a mean of three years follow-up, the patients were managed post-operatively through close clinical observation and serial MRI. None of the patients had recurrence of the disease.

Conclusion

PTs is a rare glial tumor of the sellar and suprasellar region that arises from neurohypophyseal pituicytes. Disease control may be achieved by total excision.

Pituicytoma: A Report of Two Cases and Literature Review

Introduction Pituicytoma is a rare form of primary benign tumor of the neurohypophysis and infundibulum. There have been 140 reported cases in world literature that could be found in our search. Here we discuss about the presentation, radiological features, treatment, histopathology, and immunohistochemical markers of two cases, along with a brief review of literature.

Case 1 A 48-year-old female presented with headache and painless visual loss for 4 years. Examination revealed bitemporal hemianopia and normal fundus. Hormonal profile was normal. Magnetic resonance imaging (MRI) showed 2.6 × 2.8 × 3.3 cm, thin-walled, cystic sellar and suprasellar lesions stretching the optic chiasm superiorly. Endoscopic transnasal, transsphenoidal gross total excision was done. Histopathological examination (HPE) and immunohistochemistry (IHC) were suggestive of pituicytoma.

Case 2 A 55-year-old male presented with intermittent headache and vomiting for 3 months. Examination was unremarkable. Hormonal profile was normal. MRI showed lobulated mass of size 1.4 × 1.9 × 2.0 cm, arising from anterior pituitary and extending to the suprasellar cistern. Lesion was hyperintense in T1-weighted and heterointense in T2-weighted images, and Fluid attenuated inversion recovery images (FLAIR) with homogenous contrast enhancement pushed the optic chiasm superiorly. Endoscopic transnasal partial excision of the lesion was done. HPE and IHC were suggestive of pituicytoma.

Discussion Total number of cases was 142, of which 71 were males (50%) and 71 were females (50%). Age ranged between 7 and 83 years (mean 49.2, median 48). Brain imaging was available in 110 cases. Size of the lesion varied from 4 to 72 mm (mean 27 mm). Location was either pure sellar (24.3%) or with extension into the suprasellar cistern (34.3%) and/or the cavernous sinuses (7.1%). Lesions in MRI were solid (84%) with few areas of cystic changes, while contrast enhancement of solid portion was in 92% (homogenous in 80% and heterogeneous in 20%) of the cases. One case showed features of hemorrhage while no case showed calcification. Treatment was primarily surgical (120 out of 130 cases): transsphenoidal excision in 70% of the cases and craniotomy and excision in 30%. Preoperative embolization of arterial feeders was done in two cases and postoperative radiation was given in one case. Gross total resection was done in 46.3%, subtotal resection in 40%, partial resection in 12.6%, and biopsy was done in 1.1% of the cases in the study. Follow-up ranged from 2 to 134 months (average 31.2, median 19). Recurrence or regrowth was documented in 23 patients, treatment in 18 patients, and resurgery was done in 12 cases, followed by radiotherapy in 5. In six cases, radiotherapy was used in isolation. Improvement in the visual deficit was seen in 26 patients, and remained unchanged in 3. Among the patients with preoperative endocrine dysfunction, 10 improved while 11 suffered a worsening. Ten patients had new postoperative endocrine alteration. Only one fatal case was registered.

Conclusion Pituicytoma is a rare World Health Organization grade I tumor of the sellar and suprasellar region, presenting with varied clinical, radiological, and hormonal features. Histopathology and immunohistochemistry form the mainstay in diagnosis. Surgical excision with transsphenoidal approach is ideal. Prognosis in general is good after surgical resection alone or in conjunction with radiotherapy.

A rare case report of pituicytoma with biphasic pattern and admixed with scattered Herring bodies

BACKGROUND

Pituicytoma is a rare pituitary non-neuroendocrine tumour. The awareness of pituitary non-neuroendocrine tumours has gradually increased over the past several decades, but the knowledge of some histological variants of the tumours is limited, particularly in clinicopathological significance. Here, we report a rare case of pituicytoma variant.

CASE PRESENTATION

A 71-year-old man presented with sudden symptoms of stroke including urinary incontinence, weakness in right lower limb, and trouble speaking. Physical examinations showed a right facial paralysis. The radiological examinations eventually found a 1.7 × 1.4 × 1.3 cm sellar occupied lesion. After symptomatic treatment improved the symptoms, the patient underwent transsphenoidal resection of the pituitary mass. Histologically, the tumour contained hypocellular area and hypercellular area. The hypocellular area showed elongated spindle cells arranged in a fascicular pattern around small vessels and scattered Herring bodies; the hypercellular area showed a large number of pseudorosettes. Immunohistochemistrically, the tumour cells were positive for thyroid transcription factor-1, S100, and neuron-specific enolase. Neurofilament only showed a little positive in the hypocellular area, and silver impregnation was only noted in a perivascular distribution. The patient had no recurrence 4 months after the surgery.

CONCLUSIONS

The rare variant of pituicytoma has a favourable prognosis. Moreover, it needs to be distinguished pituicytomas with pseudorosettes from ependymomas because of different prognosis. Lastly, Herring bodies may occasionally be seen in the pituicytoma, which could be a potential diagnostic pitfall.

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.

Pituicytoma: A report of three cases and literature review

Pituicytoma is a rare tumor of the sellar and suprasellar regions, arising from the pituicytes, which are specialized glial cells in the neurohypophysis and infundibulum. Due to its rarity, ambiguity persists over the diagnosis, management and prognosis of pituicytoma. The current study presents a case series of three patients, each with a histopathological diagnosis of pituicytoma. A summary of the clinical manifestations, radiological characteristics, histopathological features, treatment strategies and prognoses are presented. In addition, 78 cases of pituicytoma, identified in a search of the published literature in Pubmed, are profiled. Pituicytoma typically presents with dysfunction of the optic nerve and pituitary. The radiological characteristics are nonspecific; diagnosis is typically made on the basis of histopathological results. The tumor is slow growing and benign and is amenable to surgical treatment by gross total resection; subsequent tumor recurrence is rare. A definitive assessment of prognosis requires an extended follow-up in a larger cohort.

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.

Pituicytoma and Cushing's Disease in a 7-Year-Old Girl: A Mere Coincidence?

Pituicytoma is a tumor extremely rare in childhood, with only 4 cases reported in literature. It is thought to arise from the specialized glial elements called "pituicytes." The association of pituicytoma and Cushing's disease (CD) has been described only once so far, in an adult patient. A 7-year-old girl was referred for clinical signs of hypercortisolism, and a diagnosis of CD was made. MRI revealed 2 pathologic areas in the pituitary gland. The patient underwent surgery, with microscopic transsphenoidal approach, and a well-circumscribed area of pathologic tissue was identified and removed. Surprisingly, histologic and immunohistochemical study provided unequivocal evidence of pituicytoma. No pituitary adenoma could be identified. For persistent hypercortisolism, the patient necessitated transsphenoidal endoscopic reintervention and 2 other lesions were removed. By immunohistological examination, these lesions were confirmed to be corticotropin-secreting adenoma. Unfortunately, there was no postoperative decrease in corticotropin and cortisol levels, and the patient underwent bilateral laparoscopic adrenalectomy. Considering that we report a second case of association of pituicytoma and corticotropin-secreting adenoma, that CD is infrequent, and pituicytoma is extremely rare in childhood, the coexistence of these 2 tumors should not be considered a mere coincidence. To date, there is no conclusive evidence about the origin of these different subtypes of pituitary tumors. This case supports the hypothesis that these tumors share a common progenitor cell, which could be the folliculostellate cell.

Pituitary image: pituicytoma

INTRODUCTION

Pituicytoma is a rare tumor arising from the neurohypophysis or pars intermedia of the adenohypophysis.

CASE REPORT

A 36 year old male came to our observation presenting polydipsia, polyuria, polyphagia, decreased libido and altered sleep-wake rhythm. The biochemical tests showed hypotonic urine, mild hyperprolactinemia, hypogonadotropic hypogonadism, central hypothyroidism. Magnetic resonance revealed an expansive lesion of the suprasellar region (slightly isointense on T1, hyperintense on T2, impregnating contrast medium), that was partially removed by trans-cranial neurosurgical approach. The histopathological diagnosis was pituicytoma. After surgery, in addition to endocrine disorders, the patient presented severe neurological sequelae and hyperthermia, likely due to damage of the hypothalamus, followed by a progressive metabolic syndrome. The residual tumor was monitored by MRI, and, due to the early gradual increase in volume, was treated by stereotactic radiosurgery.

DISCUSSION/CONCLUSIONS

Pituicytomas are often difficult to distinguish from other hypothalamic or pituitary lesions. However, their identification would be preferable in a pre-operative setting in order to optimize the work-up and to initiate a proactive management of the expected complications.

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.

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.

[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.

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.

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.

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.

Classification of Neural Tumors in Laboratory Rodents, Emphasizing the Rat

Neoplasms of the nervous system, whether spontaneous or induced, are infrequent in laboratory rodents and very rare in other laboratory animal species. The morphology of neural tumors depends on the intrinsic functions and properties of the cell type, the interactions between the neoplasm and surrounding normal tissue, and regressive changes. The incidence of neural neoplasms varies with sex, location, and age of tumor onset. Although the onset of spontaneous tumor development cannot be established in routine oncogenicity studies, calculations using the time of diagnosis (day of death) have revealed significant differences in tumor biology among different rat strains. In the central nervous system, granular cell tumors (a meningioma variant), followed by glial tumors, are the most common neoplasms in rats, whereas glial cell tumors are observed most frequently in mice. Central nervous system tumors usually affect the brain rather than the spinal cord. Other than adrenal gland pheochromocytomas, the most common neoplasms of the peripheral nervous system are schwannomas. Neural tumors may develop in the central nervous system and peripheral nervous system from other cell lineages (including extraneural elements like adipose tissue and lymphocytes), but such lesions are very rare in laboratory animals.

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.

PITUICYTOMA

OBJECTIVE

Pituicytoma is a rare but distinct low-grade glioma of the neurohypophysis. To date, we have found only 28 cases reported in the literature and have reviewed these in addition to our own case to delineate the clinical implications of this relatively recently defined tumor.

CLINICAL PRESENTATION

A 71-year-old woman presented with bitemporal hemianopsia and was found to have a large sellar tumor, resembling a pituitary adenoma. Transsphenoidal resection was attempted but was complicated by significant tumor vascularity. Pathology at that time was interpreted as a “granular cell tumor.” The patient was then referred to our institution for management of the residual tumor.

INTERVENTION

The patient underwent preoperative embolization to decrease tumor vascularity, and subtotal tumor resection was performed via a craniofacial approach. Postoperatively, the patient has enjoyed significantly improved visual fields despite residual tumor. No adjuvant treatment was given. There has been no regrowth of the residual tumor, as shown on magnetic resonance imaging, over a follow-up period of 1.5 years. The final pathological diagnosis was pituicytoma.

CONCLUSION

Pituicytomas are benign, slow-growing tumors that seem to be cured by gross total resection. The role of radiation therapy is controversial. We advocate an aggressive surgical approach with possible preoperative embolization to reduce the vascularity of the tumor.

Pineocytoma and pineal parenchymal tumors of intermediate differentiation presenting cytologic pleomorphism: a multicenter study

Cytologic pleomorphism has been described in a limited number of benign pineal tumors, namely pineocytoma (PC) and pineal parenchymal tumors (PPTs) of intermediate differentiation (PPTID). We examined the clinicopathologic features in a retrospective series of 14 cases (seven females and seven males aged from 10 to 65 years) of pleomorphic PPT. Seven cases were PC, with no mitoses and with areas of tumoral cells forming large pineocytomatous rosettes and other areas with giant cells containing hyperchromatic nuclei. The other seven were PPTID, presenting few mitoses (< or =2), a Ki67 proliferation index between 3% and 7%, and predominantly composed of small neoplastic cells and scattered giant cells, sometimes multinucleated. In the 14 tumors, the proportion of pleomorphic areas was variable. Most tumoral cells showed extensive neuronal differentiation with strong expression of neuron-specific enolase, synaptophysin and neurofilaments. Some of the neoplastic cells expressed S100 protein. The follow-up period ranged from 1.2 to 13 years and only one PC and one PPTID progressed after stereotactic biopsy or incomplete resection. The lack of invasiveness and the low proliferation index of these tumors suggest a benign clinical course despite the marked pleomorphism, the latter of which can lead to upgrading.

Newly codified glial neoplasms of the 2007 WHO Classification of Tumours of the Central Nervous System: angiocentric glioma, pilomyxoid astrocytoma and pituicytoma

The 4(th) edition of the WHO Classification of Tumours of the Nervous System (WHO 2007) introduces changes that reflect both the recognition of new brain tumour types and a better understanding of neoplastic behavior. Three new tumours, angiocentric glioma (AG), pilomyxoid astrocytoma (PMA), and pituicytoma are added to the section on gliomas. AG is a slowly growing cerebral tumour that typically presents with seizures in children and young adults. It is characterized by monomorphous, bipolar tumour cells with a striking perivascular growth pattern. Although the 'cell of origin' of AG is not clear, ultrastructural evidence points to an ependymal derivation. Typically, AG can be cured by total resection, and is designated WHO grade I. PMA is a solid, circumscribed tumour occurring mainly in the hypothalamic region of young children. It is composed of a monomorphous population of bipolar tumour cells within a rich myxoid background, with a conspicuous anglocentric arrangement. While PMA is considered a more aggressive variant of pilocytic astrocytoma, this relationship awaits further clarification. The PMA has been designated WHO grade II. The pituicytoma, involves the posterior pituitary and/or its stalk and affects adults. It is solid in architecture, composed of spindle cells and presumably derived from pituicytes. Pituicytomas are indolent tumours, and are designated WHO grade I.

Lesions of the Hypothalamus: MR Imaging Diagnostic Features

The hypothalamus is susceptible to involvement by a variety of processes, including developmental abnormalities, primary tumors of the central nervous system (CNS), vascular tumors, systemic tumors affecting the CNS, and inflammatory and granulomatous diseases. The hypothalamus may also be involved by lesions arising from surrounding structures such as the pituitary gland. Magnetic resonance (MR) imaging is the modality of choice for evaluating the anatomy and pathologic conditions of the hypothalamus. The MR imaging differential diagnosis depends on accurate anatomic localization and tissue characterization of hypothalamic lesions through the recognition of their signal intensity and contrast material enhancement patterns. Diffusion-weighted imaging and proton MR spectroscopy can be helpful in differentiating among various types of hypothalamic lesions. Key MR imaging features, in addition to the patient's age and clinical findings at presentation, may be helpful in developing the differential diagnosis for lesions involving the hypothalamic region.