Basal Ganglia Intracranial Mixed Germ Cell Tumor With Predominance of Yolk Sac Component

Abstract

Abstract Introduction/Objective Primary intracranial germ cell tumors (ICGCTs) represent a rare heterogenous group of neoplasms with an overall incidence of 3% of all pediatric brain tumors. ICGCTs are classified into germinomatous and non-germinomatous tumors and approximately 25% are mixed, and contain more than one histologic component. Most ICGCTs are located in suprasellar and pineal regions with some occurring in rare locations such as basal ganglia, thalamus and fourth ventricle. Methods In our case, A 9-year-old Asian-American male presented with headaches and a few weeks history of unilateral weakness. Imaging showed a left basal ganglia lesion with midline shift. Serum AFP was elevated at 17,974.5ng/ml. Results Histology revealed a biphasic tumor with a predominant yolk-sac component composed of sheets of pleomorphic cells with prominent nucleoli, focally arranged in a reticular pattern with hyaline globules, increased mitoses and foci of necrosis. A lesser component display features of germinoma, in the form of sheets and nests of large cells with clear vacuolated cytoplasm separated by fibrous septa with lymphocytic infiltrates. Tumor cells in yolk sac component were positive for AFP, while PLAP, CD117, D240 stained germinoma component. After receiving 6 courses of chemotherapy and radiation, MRI did not show any evidence of residual disease. Conclusion Pathogenesis of ICGCT is thought to be either from primordial germ cells that have migrated aberrantly during embryonic development or from pluripotent embryonic cells that have been entrapped into lateral mesoderm due to misfolding and misplacement and then undergo malignant transformation. The outcomes of ICGCTs differ among histological subtypes. Highest survival rates are seen in patients with germinomas or mature teratomas (10- year survival rate >90% in both groups. The lowest survival rates are seen in choriocarcinoma, embryonal carcinoma and yolk sac tumor.