Histomorphological spectrum and immunohistochemical characterization of hemangioblastomas: An entity of unclear histogenesis.

ABSTRACT

Introduction: Hemangioblastomas (HBs) are rare WHO grade I neoplasms of uncertain histogenesis. Most are sporadic and association with von Hippel-Lindau disease (VHL) is uncommon. Materials and Methods: Histomorphological and immunohistochemical evaluation of 24 cases of HBs was done. Results: Age range was 15-68 yrs (median 30 yrs) with maleFemale of 1.21 (M-13; F-11). Cerebellum was commonest location (n = 20), one each was seen in brain stem, cervical spinal cord, fourth ventricle and frontal lobe, respectively. VHL association was noted in 5 cases. Four cases were recurrent in nature of which 3 were in association with vHL. Histologically, reticular variant was the predominant subtype (n = 15), 5 were of cellular variant and 4 were mixed. Nuclear pleomorphism, nuclear cytoplasmic inclusions, cytoplasmic vacuolation were noted in the stromal cells in varying proportions. Immunohistochemical evaluation was successful in only 11 cases and of which 8 showed stromal cell positivity for alpha-inhibin. CD56 (NCAM), Nestin and synaptophysin positivity was seen in 6, 7 and 4 cases, respectively. Nestin positivity was noted in stromal cells only and no reactivity with the endothelial cells seen. S-100 protein and NSE positivity was seen in 8 and 10 cases, respectively. Glial fi brillary acidic protein (GFAP) showed two distinct patterns of immunoreactivity — scattered stromal cell positivity (n5) and pattern of reactive astrogliosis positivity (n10). CD44 positivity was noted in 5 cases. VEGF and EGFR positivity was seen in 5 cases each. None of the cases showed positivity for epithelial membrane antigen and no stromal cells in any of the cases showed positivity for CD34 and CD31. Conclusion: HBs can occur in throughout the neuroaxis. Cerebellum is the commonest site of occurrence for HBs and uncommonly can occur in the supratentorial compartment and spinal cord. Its association with vHL is uncommon and no histological or immunohistochemical correlation was identifi ed with the same.