A Case of Synchronous Subcarinal Lymph Node Metastasis from Double Primary Cancers with Small Cell Lung Cancer and Prostate Cancer.

A 78-year-old man presented with a history of weight loss. A systemic examination revealed lung and prostate cancers. Endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) of a subcarinal lymph node revealed combined small-cell and non-small-cell carcinoma. Prostate-specific antigen (PSA) staining was performed to exclude distant metastases from prostate cancer. A positive result confirmed synchronous lymph node metastasis from a double cancer of small cell lung cancer and prostate cancer. When biopsies reveal multiple histological types, the possibility of metastasis from other cancer types should be carefully evaluated.