Germinoma intracraneal, 2 casos en varones adolescentes

Extragonadal germinal cell tumors located in the brain are rare and are most commonly found in the pineal and suprasellar region. Germinoma is the most frequent intracranial one. It has a good prognosis and response to treatment and a high incidence among Chinese and Japanese. When in the typical location, pineal and sellar, they display characteristic features on CT and MRI. Diagnosis confirmation requires histologic study in which they show a diffuse pattern with epithelial-type tumoral cellularity associated to a well differentiated lymphoid infiltrate. Some tumours express granulomatous reaction mimicking TBC and sarcoidosis and other have small cells that have to be differentiated with lymphomas and primitive neuroectodermic tumors. Immunohistochemical studies in germinomas show positive cytoplasmic reaction to Placental Alkaline Phosphatase (PLAP) in epithelial cells and CD3 positive in lymphoid cells. This article reports two cases of typically located intracranial germinoma in male adolescents with characteristic symptoms related to the compromise of the suprasellar and pineal region, extension to neighbouring organs and repercussion in visual, auditive and motor functions. The CT and MRI show the lesions with good definition, location, extension and the histological study reveals the presence of a biphasic histologic component: Diffuse and poorly cohesive epithelial of eosinophilic abundant cytoplasm and hyperchromic nuclei, and fine vascularized connective septa infiltrated by mature lymphoid cells organized around the capillaries. The PAS dye shows fine positivity in the cytoplasm of the epithelial cells and the immunohistochemistry for Carcinoembryonic antigen (CEA) is negative; there is also cytoplasmic positivity for PLAP in epithelial cells an CD3 positivity for septal lymphoid cells, which confirms the diagnosis of cerebral germinoma.