Fine needle aspiration cytology of metastatic choriocarcinoma presenting as a breast lump. A case report.

Background: While choriocarcinoma is a rapidly invasive, widely metastasizing malignancy, it responds well to chemotherapy, so it is important to obtain an early diagnosis. We report the fine needle aspiration cytology (FNAC) of a case of choriocarcinoma metastatic to the breast.
Case: A 48-year-old female presented with a cough, hemoptysis and epistaxis. Chest computed tomography revealed multiple nodules in both lung fields. Also, a firm, slightly tender mass in the lower outer quadrant of the left breast was palpated. The breast mass was clinically suspected to be a metastatic lung cancer. FNAC of the breast showed a malignant tumor that had been misdiagnosed as a metastatic non-small cell carcinoma of the lung. Histologic examination of a nasal biopsy revealed metastatic choriocarcinoma.
Conclusion: The cytologic features of choriocarcinoma are quite characteristic, with side-by-side, malignant, mononucleated cells and multinucleated giant cells corresponding to cytotrophoblasts and syncytiotrophoblasts, respectively. The disease is possible to diagnose by a careful examination of FNAC samples.