Aspiration biopsy cytomorphology of primary pulmonary germ cell tumor metastatic to the brain.

Extragonadal germ cell tumors are uncommon and such tumors originating from the lung parenchyma are extremely rare. This is a case of 68-year-old female who was admitted with complaints of right-sided weakness, inability to maintain her balance, right-sided headache, and bloody sputum. Her workup revealed two enhancing brain lesions and large lung mass involving the left lower lobe. Fine-needle aspiration (FNA) of the lung followed by craniotomy was performed and the patient was initially diagnosed with lung adenocarcinoma metastatic to the brain based on the cytomorphology of the lung FNA and histology of the brain mass. However, retrospective investigation revealed markedly elevated alpha fetoprotein (AFP) of which the cytopathologist was unaware at the time of diagnosis. A review of the cytology and surgical specimen slides, as well as immunohistochemistry (IHC) on the brain tumor and FNA cell block were preformed. On the basis of the slides review, clinical findings, and immunostaining results, a diagnosis of primary pulmonary mixed germ cell tumor, containing choriocarcinoma and yolk sac elements, with brain metastases, was retrospectively made. (c) 2009 Wiley-Liss, Inc.