RESUMEN
Metastatic tumors account for 5-10% of all ovarian malignancies. They are usually bilateral tumors with a multinodular surface and extensive extra ovarian spread. Lung cancer is a rare source (0.3% of metastatic ovarian tumors). Among synchronous primary cancers, ovarian cancer is most frequently associated with endometrial cancer. The differential diagnosis between a primary ovarian carcinoma, synchronous primary cancers, and metastatic ovarian carcinoma is very important, as the treatment and prognosis are markedly different. We report the case of a 25-year-old woman who had been diagnosed and treated for stage IIIB small cell lung carcinoma (SCLC). Imaging undertaken for abdominal pain revealed a unilateral 8.5 cm ovarian tumor for which adnexectomy was performed. Histology and immunohistochemistry led to the diagnosis of ovarian metastasis from SCLC, a high-grade neuroendocrine lung tumor. This patient's particular features, all infrequent in a metastatic tumor, are the lesion's unilaterality (atypical for ovarian metastases in other cancers, but often observed in SCLC), the smooth ovarian surface with intact capsule, and the absence of intra-abdominal dissemination. The patient developed liver and vertebral metastases. This report focuses on the differential diagnosis between primary and metastatic ovarian neoplasms. We performed an extensive search of the literature on SCLC and ovarian metastases. Immunohistochemistry is essential for diagnosis when imaging and the pathological evaluation of the ovarian tumor cannot make the differential diagnosis.
