Cerebral Composite Atypical Teratoid/Rhabdoid Tumor and Yolk Sac Tumor in the Frontal Lobe of an Infant

—Case Report—

抄録

A 1-year-old male infant presented with a rare cerebral composite tumor consisting of atypical teratoid/rhabdoid tumor (AT/RT) with epithelial and mesenchymal components and yolk sac tumor (YST) with Schiller-Duval bodies. He was admitted to our medical center with a 2-month history of right hemiparesis. Computed tomography and magnetic resonance imaging revealed a large, intra-axial solid tumor with a cyst in the left frontal lobe. Total resection of the tumor was performed. Histological examination showed two different main growth patterns: solid sheets of undifferentiated polygonal cells and a few rhabdoid cells with rosette structures and rhabdomyoblastic cells; and reticular or papillary structures with occasional Schiller-Duval bodies in a myxoid matrix. The immunohistochemical and electron microscopy findings indicated composite AT/RT and YST. Initial total resection of the tumor was subsequently followed by local recurrence, hydrocephalus, and spinal metastasis. Despite adjuvant chemotherapy, the patient died 9 months after admission. AT/RT is a recently established entity of the central nervous system. The present case of composite AT/RT and YST in the frontal lobe indicates the poor prognosis of such tumors.