Histological analysis of lesions of the pineal region: a retrospective study of 12 years.

Various types of tumors and non-tumor lesions arise in the pineal region. This study summarizes the experience the authors have gained with 54 lesions of the pineal region over the last 12 years. Histology was analyzed in all cases. Out of these 54 cases, four were non-tumor lesions. Of the 50 tumors, pineal parenchymal tumors (PPTs) were most common (42% (21/54)), followed by gliomas (40% (20/54)). The PPTs were pineoblastomas (10/21), PPT of intermediate differentiation (7/21), and pineocytomas (4/21). The other tumors included germ cell tumors (4/54), meningiomas (2/54), craniopharyngiomas (2/54), and choroid plexus papilloma (1/54). The non-tumor lesions were epidermoid cysts (2/54), tuberculous abscess (1/54), and cysticercosis (1/54). Immunohistochemically, all the PPTs showed cytoplasmic positivity for synaptophysin. Glial fibrillary acidic protein (GFAP) stained only the reactive astrocytes in these tumors except two cases of pineoblastoma, which showed GFAP positivity in some tumor cells, indicating glial differentiation. There are very few studies of pineal lesions, and there is no study from India in the indexed literature.