Hematogenous extraneural metastasis of the germinomatous component of a pineal mixed germ cell tumor

Abstract

A 23-year-old man presented with a mass in the pineal region and obstructive hydrocephalus. A neuroendoscopicbiopsy for the lesion, ventriculoperitoneal (VP)shunting, and focal irradiation were conducted as initial treatment. Histological diagnosis of the biopsy specimen was germinoma. He underwent further irradiation and two tumor resections. Histological diagnosis was mature teratoma without a germinomatous component. After serial treatments, the intracranial lesion was controlled. However,14 months after presentation, extraneural lesions were confirmed in the posterior mediastinum and retroperitoneal space. The biopsy specimen of the retroperitoneal space lesion was histologically diagnosed as germinoma. Although chemotherapy with cisplatin and etoposide was undertaken,extraneural lesions ware uncontrollable and he died. At autopsy, extraneural lesions were confirmed in the posterior mediastinum, retroperitoneal space, and right lung. Histological diagnosis of extraneural lesions was germinoma.This case was considered to be a pineal mixed germ cell tumor mainly consisting of germinoma and mature teratoma,which caused hematogenous metastasis of the germinoma component. Systemic chemotherapy and irradiation for primary lesions as an initial treatment is important to cure the primary lesion and prevent extraneural metastasis.

Fig. 1

Initial plain CT scans (a axial image, b sagittal image) showing a mixed density mass with calcification in the pineal region and hydrocephalus

Fig. 2

MR images taken during the course. a–c MRI with contrast during radiation showing enlargement of the tumor, indicating growing teratoma syndrome. d–f MRI with contrast after the third surgery showing a residual lesion on the right side of the third ventricle

Fig. 3

Chest and abdominal CT scans with contrast. a, b Nine months after presentation showing no lesions. c, d Fourteen months after presentation showing tumors in the posterior mediastinum and retroperitoneal space (arrows)

Fig. 4

Photomicrographs of histological findings. a, b Initial biopsy specimen showing two-cell pattern of germinoma with large clear cells and small lymphoid elements. Immunohistochemical staining for PLAP revealed positive cells. (a H&E stain, b PLAP ×100). The specimens from the second surgery showed mature teratoma features with cartilage (c) and stratified squamous epithelium (d) (H&E stain ×200). e, f Biopsy specimen from retroperitoneal space lesion showing two-cell pattern of germinoma. Immunohistochemical staining for PLAP revealed positive tumor cells (e H&E stain, f PLAP ×200)

Fig. 5

Macro and micrographs at autopsy. a Metastatic lesions of the posterior mediastinum (arrow) and retroperitoneal space (asterisk). Heart, lungs, liver, stomach, small intestine and large intestine were resected. The retroperitoneal space lesion (asterisk) encased the aorta, left adrenal grand, and the duodenum. b, c Histological findings from the posterior mediastinal lesion showing large tumor cells of germinoma. Immunohistochemical staining for PLAP revealed positive cells (b H&E stain, c PLAP ×200). d Histological findings of retroperitoneal space lesion showing degenerated tumor cells and adrenal tissue (asterisk). e Histological findings of lung lesion. f Residual lesion on the right side of third ventricle (arrow). g Histological findings of residual tumor showing mature teratoma features with cartilage and glandular elements (H&E stain ×200)