Contributed by Podgórski Andrzej1, Zielinski Grzegorz1, Grala Bartlomiej2, Koziarski Andrzej1
1Department of Neurosurgery, Military Institute of Medicine, Warsaw, Poland
2Department of Pathology, Military Institute of Medicine, Warsaw, Poland
A 50-year old male with a history of type 2 diabetes, hypertension and a nontoxic goiter, was referred to a neurosurgical center due to a newly diagnosed hypothalamic mass. He had been previously admitted to his local hospital due to somnolence, inadequate behaviour and memory disturbances of about two-week duration. His blood glucose levels were regularly measured and were known to be normal through the preceeding weeks. A full endocrinologic check-up showed normal levels of all measured hormones and no alteration of their circadian rhythms.
An initial CT brain scan was followed by an MRI examination, which revealed an oval 27-milimeter pathologic mass located in the hypothalamus with signs of compression of cerebral peduncles and oedema extending laterally towards the basal ganglia. There were no signs of infiltration of the surrounding brain tissue. The tumor was heterogenous, hypointense on T1-weighted images (Fig. 1A) and hyperintense on T2-weighted images (Fig. 1B). T1-weighted sequences additionally showed an area of probable small bleed at the junction between the tumor and the left cerebral peduncle. After administration of gadolinum, the tumor showed a strong homogenous enhancement (Fig. 1C). An initial radiological diagnosis of atypical meningioma or astrocytoma was made.
The patient was admitted to our center for surgical treatment. Neurologic examination on admission revealed mild confusion and short term memory disturbances. A right-sided temporal craniotomy was performed to remove the tumor, which turned out to be solid and well separated from the surrounding structures as well as heavily bleeding on any attempts of its manipulation. Despite the technical challenge, complete removal of the tumor was achieved.
The resected tissue samples were routinely fixed in neutral buffered formalin, embedded in paraffin and stained with hematoxylin and eosin. For immunohistochemical staining the entire pre-treatment process of deparaffinization, rehydration and epitope retrieval was done automatically using Dako PT-Link system. Immunohistochemical staining was performed according to the Dako labelled EnVision™ Flex Visualization System with DAB as chromogen (K8000), using primary anti-human antibodies from Dako against: NSE (BBS/NC/VI-H14 clone, IR612), S-100 protein, polyclonal (IR504), GFAP, polyclonal (IR524), EMA (E29 clone, IR629), cytokeratin (AE1/AE3 clone, IR053) and inhibin alpha (R1 clone, IR058). The additional reticulin stain of tissue sample was performed using automatic Dako Artisan Link Pro staining system.
Histopathology revealed a tumor composed of neoplastic stromal cells accompanied by dense network of capillaries (Fig. 1D). In some parts of the tumor the stromal cells were of greater size with abundant, finely granular and lightly eosinophilic cytoplasm (Fig. 1E), while in other areas they had clear or vacuolated cytoplasm and small hyperchromatic nuclei (Fig. 1F), The latter parts of tumor were characterized by a denser capillary and reticulin fiber network than the former ones (Fig. 1G). No mitotic activity was observed. Tumor necrosis was absent. On immunohistochemistry stromal cells of both type were strongly positive for NSE and S100 (Figs. 1H and 1I respectively), negative for GFAP, EMA, and cytokeratins (Figs. 1J, 1K, and 1L) respectively) and weakly positive for inhibin (Fig. 1M). What is your diagnosis?