Perren, I.

Bravi, L. Jennen, A. Feuchtinger, J. Drouin, F. Roncaroli and N. S. Pellegata (2013) Neuropathology and Applied Neurobiology39, 256–269 Characterization of MENX-associated pituitary tumours Aims: The aim of this study is to evaluate the pathological features, serum hormone levels and ex vivo cultures of pituitary adenomas that occur in rats affected by MENX syndrome. MENX is multiple endocrine neoplasia syndrome caused by a germline Erlotinib in vivo mutation in the cell cycle inhibitor p27. Characterization of MENX adenomas is a prerequisite to exploit this animal model for molecular and translational studies of pituitary adenomas. Methods: We investigated MENX pituitary adenomas with immunohistochemistry, double immunofluorescence, electron microscopy, reverse transcription

polymerase chain reaction (RT-PCR), measurement of serum hormone levels and ex vivo cultures. Results: Adenomas BAY 57-1293 concentration in MENX rats belong to the gonadotroph lineage. They start from 4 months of age as multiple neoplastic nodules and progress to become large lesions that efface the gland. Adenomas are composed of chromophobic cells predominantly expressing the glycoprotein alpha-subunit (αGSU). They show mitotic activity and high Ki67 labelling. A few neoplastic cells co-express gonadotropins and the transcription factor steroidogenic factor 1, together with growth hormone or prolactin and Pit-1, suggesting that they are not fully committed to one Ribonucleotide reductase cell lineage. Ex vivo cultures show features similar to the primary tumour. Conclusions: Our results suggest that p27 function is critical to regulate gonadotroph cells growth. The MENX syndrome represents a unique model to elucidate the physiological and molecular mechanisms mediating the pathogenesis of gonadotroph adenomas. “
“Intracranial malignant solitary fibrous tumor (SFT) is very rare. It was identified in a 39-year-old female patient who underwent malignant transformation over 6 months. MRI revealed an 8 × 5 × 6 cm mass with heterogenous strong enhancement in the left occipital lobe. Histologic findings and immunophenotype (positive for CD34, bcl-2 and vimentin, and negative for epithelial membrane

antigen or S100 protein) of the primary tumor were typical of SFT. However, there was a focal area (<10% of tumor volume) showing hypercellularity, nuclear pleomorphism and increased Ki-67 labeling index (LI) of 10% (average, 1%). At the second operation, the recurrent tumor revealed full-blown histologic features of malignant SFT, such as infiltrative brain invasion, marked nuclear pleomorphism, frequent mitotic figures (15/10 high power fields), and high Ki-67 LI (25%). The presence of atypical histologic finding or increased Ki-67 LI in the typical SFT, although it is focal, needs to be mentioned in the diagnosis and also may require more aggressive surgical management. "
“Circumventricular organs (CVOs) are specialized ventricular structures around the third and fourth ventricles of the brain.