A rare giant mixed germ cell tumor of the pineal region with immature elements: Case report and review of the literature

Abstract

The diagnosis and management of mixed intracranial germ cell tumors may be complicated by the diversity present within this tumor category. Mixed germ cell tumors demonstrate variable natural histories which may be altered by the inclusion of even the most minute immature histological components. We report the case of an 18-year-old male who presented with a 3-month history of progressive headache and nausea leading to lethargy. Imaging revealed a giant pineal region mass extending superiorly from the roof of the fourth ventricle into the lateral ventricle, with resultant obstructive hydrocephalus. No spinal lesions were noted. Following gross total resection, the patient experienced marked improvement. Pathologic analysis identified an uncommon tumor composition: mature teratoma (96%), immature teratoma (2%), and germinoma (2%). Guided by the immature component, chemotherapy and radiation were added post-operatively to provide this patient with the greatest chance of long-term survival. Intracranial pathology, including germ cell tumors, should be included in the differential for any young patient presenting with new and progressive headache and nausea. This case emphasizes the benefit of a multimodal approach to mixed germ cell tumors of the pineal region and the importance of careful pathologic review of all submitted material.

Keywords: Pineal; germinoma; histology; immature teratoma; mixed germ cell tumor.

Figure 1.

Preoperative sagittal (a) and coronal (b) T1 with contrast MRI demonstrating giant germ cell tumor of the pineal region. Postoperative sagittal (c) and coronal (d) T1 with contrast MRI following gross-total tumor resection.

Figure 2.

The histopathologic features of the resected mass were that of a tan-gray, semisolid, semicystic glial neoplasm exhibiting mitoses, and vascular proliferation. Mature teratoma with features of the gastrointestinal tract (a) makes up the bulk of the tumor with a minor glial component (b). There are small foci with features of ganglioneuroblastoma (c) which would classify this tumor as an immature teratoma. In a separate focus, there is an area with seminomatous component ((d) area between arrows). Prominent nucleoli are present ((e) small arrows) and these cells are positive for OCT 3/4 on immunohistochemistry (f) (original magnification: a to d are 20×; e and f, and all insets are 60×).