Cerebellar Hemangioblastoma: Four Case Reports and Review of the Literature

Hemangioblastoma (HB) is a benign, slow-growing, highly vascular tumour of not well defined histological origin. These tumors make up about 1 to 2 percent of all intracranial neoplasms and occur primarily in the posterior fossa. Hemangioblastomas can occur sporadically but in about 20% to 30% cases, it is associated with von Hippel-Lindau (VHL) disease. Four cases of cerebellar haemangioblastoma, not associated with von Hippel-Lindau disease (sporadic haemangioblastomas), were presented and reviewed the relevant literature. Four hemangioblastomas of the central nervous system were examined with haematoxylin & eosin (H&E), reticulin stain and with a panel of antibodies including CD34, vimentin, NSE, S-100, CD99, CD56, GFAP, cytoceratin, epithelial membrane antigen (EMA), CD10. Of the 4 patients in this study 1 was male and 3 were female. Their ages ranged from 46 years to 60 years with a mean age of 54.75 years. All of them were as cystic nodules about 2-3 cm in diameter. In the histopathological examination, the tumors sections showed large and vacuolated stromal cells and numerous arborizing capillary-size blood vessels. Some tumors showed atypical nuclei. Vimentin was strongly positive both stromal cells and blood veessels in all tumors. In 4 cases of HB, some stromal cells were positive for NSE and CD99. Three tumors were positive for S-100 and CD56, two tumors were focally positive for glial fibrillary acidic protein (GFAP). CD34 immunostaining highlighted the arborizing and complex vascular network, whereas the tumor stromal cells were negative. The stromal cells were negative for epithelial markers such as cytokeratin, EMA and CD10. Ki-67 index was less than 1% of the tumor cells. Hemangioblastoma, a rare, benign tumors of uncertain histogenesis, is characterized histologically by the presence of vacuolated, lipid containing cells and a well developed, fine capillary network. The main histological differential diagnosis of HB is metastatic clear cell carcinoma. Additionally, because of the cystic mural features, pilocytic astrocytomas of the cerebellum must be separated from haemangioblastomas.