Endocrine Abstracts

Introduction: The differential diagnosis of sellar masses is broad and includes - apart from the most common pituitary adenomas - other neoplasms such as craniopharyngiomas, germinomas, gliomas, meningiomas, and others. Hemangiopericytoma (HPC) is a rare vascular tumor arising from pericytes that may appear at any site of the body. We report an unusual case of an intrasellar HPC.

Case Report: A 63-year-old woman was admitted to our hospital complaining about headaches for twelve, frequently occurring orthostatic dizziness for six and progressive visual field defects for two months. Kinetic perimetry confirmed bitemporal hemianopia, and magnetic resonance imaging (MRI) revealed a sellar mass (27 mm) which compromised the optic chiasm. The sellar mass appeared homogenous, hyperintense on T2-weighted and isointense compared to brain parenchyma on T1-weighted MRI. On admission, pituitary insufficiency was diagnosed (random cortisol 160 nmol/l; TSH 2.4 mU/l; fT4 5.7 pmol/l; prolactin 121 ug/l; IGF-1 139 ug/l). Fluid intake and thirst were adequate. Cortisol and thyroxine were replaced. The patient underwent transsphenoidal resection. Intraoperatively, the tissue had an unusual consistency with an increased bleeding tendency as compared with typical pituitary adenoma. The intraoperative frozen section revealed tissue compatible with pituitary adenoma. After surgery, headaches and bitemporal hemianopia disappeared but adrenal insufficiency and hypothyroidism persisted. The final histo-pathological examination revealed a pleomorphic, highly vascular and cellular tumor. The tumor cells were immune-positive for STAT6, negative for CK8a, synaptophysin and TTF1. The proliferation index Mib-1 (Ki-67) was 10%. Based on these findings, the diagnosis of an HPC grade 2 was made.

Discussion: HPC are very rare intracranial tumors (<2.5% of all meningeal and <1% of primary intracranial tumors). However, a few cases of HPC presenting as a sellar mass have been described. Often they mimic a pituitary adenoma. The reported patients presented with visual field defects (reported in seven of twelve, just one with normal visual field) and headaches (reported in six of twelve). Data on pituitary function was available in six of twelve: two with normal pituitary profile; one with elevated prolactin; one with hypogonadism and adrenal insufficiency; one with adrenal insufficiency. In five of twelve cases visual field defects and pituitary insufficiency improved after surgery. Anyway, surgical resection is mandatory due to a high risk of progression, metastasis and relapse rates (up to 70%). Postoperative radiotherapy might be discussed in tumor boards with decision based on imaging and histopathological findings, and clinical aspects.