International Journal of Clinical Cases and Investigations Volume 5 (Issue 3), 18:23, 1 st October 2013

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1 Case Report Neurohypophysis Tumors. Faiza Belhimer, Farida Chentli, Department of endocrine and metabolic diseases, Bab El Oued Universitary Hospital Algiers, Algeria. International Journal of Clinical Cases and Investigations Volume 5 (Issue 3), 18:23, 1 st October 2013 Keywords : Neurohypophysis tumor, pituicytoma, diabetes insipidus, pituitary insufficiency, optic atrophy Abstract:- Introduction: Neurohypophysis tumors (NHPT) named pituicytomas are very rare tumors as less than 60 cases have been reported so far. Our aim was to report two cases observed in our practice with literature review. Observations: Case1: A woman aged 33 consulted for polyuria and polydypsia. The diagnosis was central diabetes insipidus (CDI) without pituitary insufficiency. MRI discovered a 7mm tumor in the posterior part of the pituitary gland. According to different investigations a primary lesion was more likely than a metastasis. Case2. A man aged 55, was referred for headaches and visual troubles. Brain MRI showed a pituitary tumor measuring 55x32mm. Hormonal exploration pleaded for a non functioning tumor with anterior pituitary deficits, without CDI. Histological examination and immunohistochemy pleaded for a pituicytoma. Conclusion: NHPT are deemed to be rare. They may be very small with CDI as the only manifestation as in our first case, or be large with ophthalmological troubles and pituitary insufficiency without CDI mimicking an anterior pituitary tumor as in our second case. Pituitary surgery is the best treatment for large tumors, but for small ones wait and see attitude can be considered as they are slow growing and much vascularized which makes surgery sometimes too risky. Radiotherapy is still debated. Introduction Posterior pituitary tumors (PPT) are low-grade gliomas (WHO 2007) originating from the neurohypophysis or the infundibulum 1,2. The first case was described in These tumors are exceedingly rare. Till now less than 60 cases have been reported 1. They are usually called pituicytomas as they arise from the neurohypophysis 18

2 stroma s cells named pituicytes. Other names are choristomas, granular cell tumors, Abrikossoff s tumors and pilocytic astrocytoma 3. They are deemed to be benign and slow growing 4. Our aim was to describe two cases observed in our practice, and to review the literature about the subject. Observations: Case1: a woman aged 33 consulted for polyuria and polydypsia. The diagnosis was central diabetes insipidus [Diuresis =4.5l/24H, urine specific gravity (USG) =1005] without pituitary insufficiency [Cortisol =413nmol/l (n: nmol/l); free thyroxin (FT4)=20pmol/l (n: 8-24); estradiol= 227pmol/l (n: ), follicle stimulating hormone (FSH) = 8.8mu/ml (n=2-10), luteinizing hormone (LH) = 4.3mu/ml (2.2-8), growth hormone (GH)= 0.78mUI/ml (n<20), median prolactin (PRL)=37ng/ml (n=10-20)]. Cerebral MRI discovered a well limited tumor in the posterior part of the pituitary gland measuring 7 mm in height, with a lack of posterior pituitary signal (fig1). Fig.1: Brain MRI showing a 7x5mm, well limited, but heterogeneous (with central necrosis) mass in posterior pituitary area that pushes up and foreword the pituitary stalk. The posterior pituitary signal is lacking. According to our different investigations a primary lesion was more likely than breast, thyroid, pulmonary or genital metastasis. She was treated with Desmopressin which normalized urine wasting and USG. For the tumor we opted for wait and see attitude. After 4 years the tumour s size is still the same. Case 2: a man aged 55, consulted for headaches and decrease in visual acuity. Clinical examination showed gynecomastia (Tanner s stage 3) with hypogonadism. 19

3 Brain MRI showed an invasive pituitary tumor measuring 55x35x32mm. The posterior pituitary signal was lacking (fig.2). Fig.2: MRI showing a huge heterogeneous pituitary process measuring 55x35x32 mm with infra, lateral, and suprasellar extension, arriving to the third ventricle. Remark the lack of posterior pituitary signal. Hormonal exploration pleaded for a total pituitary insufficiency [Cortisol=44nmol/l (n: nmol/l), FT4=3.39pmol/l (n: 8-24), Testosterone = 0.21nmol/l (n: 10-41), PRL= 4ng/ml (n=5-15), GH= 0.34mUI/ml (<20)]. Posterior pituitary function was normal: diuresis= 1.3l/24h, urine gravity=1020. Ophthalmological examination showed a low visual acuity=1/10 for the right eye and 3/10 for the left one, and optic atrophy with degenerative maculopathy. He was operated on, and had partial resection of the tumor without any problem. Histological examination argued for a typical pituicytoma with spindle shaped cells arranged in fascicles, with elongated nuclei (Fig.3): 20

4 Fig.3: Histological study showing spindle-shaped cells arranged in fascicles, with elongated nuclei. Immunostaining was positive for S-100 protein, vimentin, glial fibrillary acidic protein (GFAP) and epithelial membrane antigen (EMA). Discussion Pituicytomas are exceedingly rare, indolent and benign tumors arising from pituicytes of the neurohypophysis and pituitary stalk. They are usually located in sellar and suprasellar region, and are mimicking non functioning tumors 5 as in our second observation. In adulthood they seem more frequent in men 4. But, they are also observed in children 6, adolescent 7 and in elderly 8. Clinical symptoms are variable according to their location. Curiously, they scarcely lead to diabetes insipidus as in our second case. But, they can be revealed by visual troubles (in about 74%) or sign of infundibular compression such as hyper prolactinemia 4. That one may be discrete as in our case, or moderate 4. An association with Cushing disease is also reported 9. Rarely they are diagnosed incidentally 10, after apoplexy 11 or discovered by autopsy 12. On the histological side, pituicytomas are composed of elongated spindle-shaped cells arranged in interlacing fascicles or in a storm form structure 4. For immunestaining they react positively with vimentin, S-100 protein, glial fibrillary acidic protein (GFAP), and occasionally with cytoplasmic epithelial membrane antigen (EMA) as we observed it. But, they do not react with pituitary hormones, chromagranin, synaptophysin, and neurofilament protein 13. These tumors raise differential diagnoses particularly with metastasis from breast, thyroid, colon, stomach, and gynecological area. When the last ones are excluded, 21

5 posterior craniopharyngioma should be excluded too. Spindle cell astrocytoma, spindle cell oncocytoma, and granular cell tumor 14,15 should be discussed by the pathologist as all these tumors are entities with confusing nomenclature, histogenesis, and imaging characteristics 15. According to Phillips 16 only genomic hybridation can distinguish the pituicytoma. The best treatment for large posterior pituitary tumor is surgery. Total resection, if possible, is mandatory as subtotal resection can lead to local re-growth. Preoperative embolization can be done as the tumors are highly vascularized. Adjuvant radiotherapy is still debated as these tumors are slow growing. For small tumor, abstention or wait and see attitude is still recommended as there is not any medication available for these neoformations. Conclusion Neurohypophysis tumors are very rare. Their aspect varies from very small tumors with diabetes insipidus to giant ones with visual troubles and pituitary deficits mimicking an anterior pituitary adenoma. Surgery is considered as the best treatment for large tumors. But, when tumor resection is incomplete, it is difficult to say if one should add radiotherapy or not. That one is still controversial because of posterior pituitary tumor low progression. References 1. Secci F, Merciadri P, Rossi DC, D'Andrea A, Zona G. Pituicytomas: radiological findings, clinical behavior and surgical management. Acta Neurochir (Wien). 2012;154: Ellis JA, Tsankova NM, D'Amico R, Ausiello JC, Canoll P, Rosenblum MK, Bruce JN. Epithelioid Pituicytoma. World Neurosurg [Epub ahead of print] 3. Rossi ML, Bevan JS, Esiri MM, Hughes JT, Adams CB. Pituicytoma (pilocytic astrocytoma). Case report. J Neurosurg. 1987; 67: Chu J, Yang Z, Meng Q, Yang J. Pituicytoma: case report and literature review. Br J Radiol. 2011; 84: e Furtado SV, Ghosal N, Venkatesh PK, Gupta K, Hegde AS. Diagnostic and clinical implications of pituicytoma. J Clin Neurosci. 2010; 17: Yilmaz O, Turan A, Yigit H, Duymus M, Kosar U. Case of pituicytoma in childhood. Childs Nerv Syst. 2012; 28: Brandao RA, Braga MH, de Souza AA, Reis BL, Faraj de Lima FB. Pituicytoma. Surg Neurol Int. 2010; 13: Cenacchi G, Giovenali P, Castrioto C, Giangaspero F. Pituicytoma: ultrastructural evidence of a possible origin from folliculo-stellate cells of the adenohypophysis. Ultrastruct Pathol. 2001; 25: Schmalisch K, Schittenhelm J, Ebner FH, Beuschlein F, Honegger J, Beschorner R. Pituicytoma in a patient with Cushing's disease: case report and review of the literature. Pituitary. 2012;15 Suppl 1:S Grote A, Kovacs A, Clusmann H, Becker AJ, Niehusmann P. Incidental pituicytoma after accidental head trauma: case report and review of literature. Clin Neuropathol. 2010; 29:

6 11. Beveniste RJ, Purohit D, Byun H. Pituicytoma presenting with spontaneous hemorrhage. Pituitary 2006; 9: Takei H, Goodman JC, Tanaka S, Bhatacharjee MB, Bahrami A, Powell SZ. Pituicytoma incidentally found at autopsy. Pathol Int 2005; 55: Brat DJ, Scheithauer BW, Fuller GN, Tihan T. Newly codified glial neoplasms of the 2007 WHO classification of tumours of the central nervous system: angiocentric glioma, pilomyxiod astrocytoma and pituicytoma. Brain Pathol 2007; 17: Ogiwara H, Dubner S, Shafizadeh S, Raizer J, Chandler JP. Spindle cell oncocytoma of the pituitary and pituicytoma: Two tumors mimicking pituitary adenoma. Surg Neurol Int. 2011; 2: Covington MF, Chin SS, Osborn AG. Pituicytoma, spindle cell oncocytoma, and granular cell tumor: clarification and meta-analysis of the world literature since AJNR Am J Neuroradiol. 2011; 32: 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: