Abstract
In an autopsy of a 16-year-old female with a primary intracranial yolk sac tumor (endodermal sinus tumor), histological evaluation of the surgical specimen obtained from the pineal region showed proliferation of undifferentiated neoplastic embryonal cells without characteristic histological features, such as periodic acid-Schiff-positive hyaline droplets or Schiller-Duval bodies. Ultrastructural study of the tumor cells, however, revealed typical cytological features of yolk sac tumor, including a voluminous, homogeneous, basement membrane-like substance, both within and outside of the cells, and intracytoplasmic vesicles containing amorphous material. Alpha-fetoprotein was detected in serum and cerebrospinal fluid by radioimmunoassay and within tumor tissues by immunohistochemical techniques. After surgery, chemotherapy with cis-diamminedichloroplatinum (II), vinblastine, and bleomycin was employed without significant benefit, and the patient died 5 months after tumor removal. Histological examination of the tumor at autopsy supported the diagnosis of yolk sac tumor. Electron microscopic and immunohistochemical studies of germ cell tumors are discussed.
