====== Pituicytoma ======


Pituicytoma is a rare glial neoplasm from [[pituicyte]]s of the [[neurohypophysis]] or [[infundibulum]]. It occurs in the sella and suprasellar area, and it is extremely uncommon to observe [[intraventricular pituicytoma]] without affecting the infundibulum or [[infundibular recess]].
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Posterior lobe tumors, the family of [[pituicyte tumor]]s, include the traditional [[pituicytoma]], the oncocytic form ([[spindle cell oncocytoma]]), the granular cell form ([[granular cell tumor]]), and the ependymal type ([[sellar ependymoma]]). Although these historical terms are entrenched in the [[literature]], they are nonspecific and confusing, such that [[oncocytic pituicytoma]], [[granular cell pituicytoma]], and [[ependymal pituicytoma]] are now proposed as more accurate 
((Asa SL, Mete O, Perry A, Osamura RY. Overview of the [[2022]] [[WHO]] [[Classification]] of [[Pituitary Tumor]]s. Endocr Pathol. 2022 Mar;33(1):6-26. doi: 10.1007/s12022-022-09703-7. Epub 2022 Mar 15. PMID: 35291028.))

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In [[2017]], changes in the classification of non-neuroendocrine tumors are also proposed, in particular those tumors arising in the posterior pituitary including [[pituicytoma]]
((Lopes MBS. The 2017 World Health Organization classification of tumors of the 
pituitary gland: a summary. Acta Neuropathol. 2017 Oct;134(4):521-535. doi:
10.1007/s00401-017-1769-8. Epub 2017 Aug 18. Review. PubMed PMID: 28821944.
)).

Pituicytoma is a rare [[glia]]l [[sella]]r/[[suprasellar]] [[neoplasm]] arising in the [[neurohypophysis]] with a possible origin from the [[folliculostellate cell]]s of the [[adenohypophysis]] which are non-endocrine spindled cells expressing [[S-100]] and [[Bcl-2]]
((Phillips JJ, Misra A, Feuerstein BG, Kunwar S, Tihan T. Pituicytoma: Characterization of a unique neoplasm by histology, immunohistochemistry, ultrastructure, and array-based comparative genomic hybridization. Arch Pathol Lab Med 2010;134:1063-9.))
((Koutourousiou M, Gardner PA, Kofler JK, Fernandez-Miranda JC, Snyderman CH,
Lunsford LD. Rare infundibular tumors: clinical presentation, imaging findings,
and the role of endoscopic endonasal surgery in their management. J Neurol Surg B
Skull Base. 2013 Feb;74(1):1-11. doi: 10.1055/s-0032-1329619. Epub 2012 Dec 31.
PubMed PMID: 24436883; PubMed Central PMCID: PMC3699169.)).

Pituicytoma is considered to be a distinct Grade I neoplasm
((Louis DN, Ohgaki H, Wiestler OD, Cavenee WK, Burger PC, Jouvet A, et al. The 2007 WHO classification of tumours of the central nervous system. Acta Neuropathol 2007;114:97-109.)).


Although usually intra-sellar, pituicytomas can have suprasellar extension; however, purely suprasellar examples although rare have been reported
((Zhang F, Chen J, You C. Pituicytoma: Case report and review of the literature. Neurol India 2010;58:799-801.)).

===== Epidemiology =====

PTs had a higher prevalence in the fifth and sixth decades of life, with a slight male predominance.
((Salge-Arrieta FJ, Carrasco-Moro R, Rodríguez-Berrocal V, Pian H, Martínez-San 
Millán JS, Iglesias P, Ley-Urzáiz L. Clinical features, diagnosis and therapy of 
pituicytoma: an update. J Endocrinol Invest. 2018 Jul 20. doi:
10.1007/s40618-018-0923-z. [Epub ahead of print] Review. PubMed PMID: 30030746.
)). 
((Louis DN, Ohgaki H, Wiestler OD, Cavenee WK "WHO Classification of Tumours of the Central Nervous System. 4th Edition Revised" ISBN: 9789283244929))
===== Clinical features =====

The presenting symptoms are due to the mass effect of the tumor and include visual disturbances caused by direct compression on the optic chiasm, headaches, endocrinological symptoms and rarely diabetes insipidus
((Chu J, Yang Z, Meng Q, Yang J. Pituicytoma: Case report and literature review. Br J Radiol 2011;84:e55-7.)).

===== Diagnosis =====

[[Pituicytoma Diagnosis]]


====Subtypes====
TTF-1 Expressing Sellar Neoplasm with Ependymal Rosettes and Oncocytic Change: Mixed Ependymal and Oncocytic Variant
((Saeed Kamil Z, Sinson G, Gucer H, Asa SL, Mete O. TTF-1 Expressing Sellar
Neoplasm with Ependymal Rosettes and Oncocytic Change: Mixed Ependymal and
Oncocytic Variant Pituicytoma. Endocr Pathol. 2013 Nov 16. [Epub ahead of print] 
PubMed PMID: 24242699.)).

===== Differential Diagnosis =====

When small, and clearly localized to the infundibulum the main differential includes: 

granular cell tumors of the pituitary region

craniopharyngioma

When larger, then it is difficult to anticipate the diagnosis with other diagnoses being far more common, including: 

pituitary macroadenoma

meningioma

pituitary metastasis

pituitary infiltration

lymphocytic hypophysitis

neurosarcoidosis

optic pathway glioma
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Absent Rosenthal fibers and eosinophilic granular bodies, usually help to distinguish between pituicytomas and pilocytic astrocytomas
((Nakasu Y, Nakasu S, Saito A, Horiguchi S, Kameya T. Pituicytoma. Two case reports. Neurol Med Chir (Tokyo). 2006 Mar;46(3):152-6. doi: 10.2176/nmc.46.152. PMID: 16565586.)). 
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Amongst the various sellar tumors, pituicytoma and spindle cell oncocytoma (SCO) have considerable overlap in histological, Immunohistochemical (IHC) profile and can have extensive intraoperative bleeding making complete excision difficult with increased chances of recurrence. It is important to differentiate pituicytoma from SCO since the former is associated with a slightly better prognosis with recurrence being uncommon after complete surgical excision. Till 2013, out of 29 cases of pituicytoma with a detailed follow-up, recurrence was seen in six cases, all of which were found to have an incomplete resection during the first surgery
((Ogiwara H, Dubner S, Shafizadeh S, Raizer J, Chandler JP. Spindle cell oncocytoma of the pituitary and pituicytoma: Two tumors mimicking pituitary neuroendocrine tumor. Surg Neurol Int 2011;2:116.)).

SCO on the other hand have a tendency to recur even after complete excision. Hence, it is advocated to combine surgery with adjuvant radiotherapy in all cases of SCO to reduce the chances of recurrence. EMA is strongly positive in SCO, thus it can help to differentiate pituicytoma from SCO
((Ogiwara H, Dubner S, Shafizadeh S, Raizer J, Chandler JP. Spindle cell oncocytoma of the pituitary and pituicytoma: Two tumors mimicking pituitary neuroendocrine tumor. Surg Neurol Int 2011;2:116.)).

===== Treatment =====

see [[Pituicytoma treatment]].

===== Review =====

Less than 50 cases have been reported in the world literature till 2013
((Shenoy AS, Desai HM, Mehta JK. Pituicytoma: a case report with literature
revisited. Indian J Pathol Microbiol. 2013 Apr-Jun;56(2):180-1. doi:
10.4103/0377-4929.118695. PubMed PMID: 24056664.)).

Salge-Arrieta et al., from the [[Ramón y Cajal University Hospital]] [[Madrid]], [[Spain]], published a retrospective [[review]] of case reports published in the scientific [[literature]] to 2018, including a new illustrative example treated.

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.

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
((Salge-Arrieta FJ, Carrasco-Moro R, Rodríguez-Berrocal V, Pian H, Martínez-San 
Millán JS, Iglesias P, Ley-Urzáiz L. Clinical features, diagnosis and therapy of 
pituicytoma: an update. J Endocrinol Invest. 2018 Jul 20. doi:
10.1007/s40618-018-0923-z. [Epub ahead of print] Review. PubMed PMID: 30030746.
)).
===== Case series =====

[[Pituicytoma Case Series]].

===== References =====