A Sertoli cell carcinoma of the ovary with lung metastases mimicking neuroendocrine carcinoma is presented. Lung metastases frequently occur. Primary and secondary tumors may exhibit similar growth patterns and differentiating primary from secondary tumors may be troublesome. This process may be more difficult when metastases occur from a tumor in which metastases are uncommon and morphologically resemble only a small portion of the primary tumor. We report the case of a 52-year-old woman who underwent resection of a 4,550-g Sertoli cell tumor of the ovary. Histologically, in addition to the characteristic tubular pattern of growth, 5% of the tumor consisted of poorly differentiated areas with tumor cells in sheets, a high mitotic rate, and areas of necrosis. Eleven months after this surgery she presented at a different institution with multiple pulmonary nodules. Microscopic examination of a subsequently resected lung nodule showed histologic findings similar to those of the poorly differentiated areas of the ovarian tumor and initial immunohistochemical studies showed positive staining for cytokeratin, neuron-specific enolase, and focal positivity for synaptophysin. Without knowledge of the ovarian tumor the lung lesion was interpreted as large-cell neuroendocrine carcinoma. On review of the clinical history and comparison with the previous surgical material, however, both tumors showed similar light microscopy and immunohistochemical reactivity, and a final diagnosis of metastatic Sertoli cell tumor was made. Immunohistochemical staining for inhibin revealed weak positivity in the poorly differentiated areas of the ovarian tumor but not in the lung metastasis. This is one of the rare reports of ovarian Sertoli cell tumor metastasizing to the lungs and it emphasizes the importance of complete clinical histories, ancillary studies, appropriate sampling, and review of archival material in such unusual cases.