A Resected Melanoma of the Lung Metastasized from an Occult Skin Lesion: A Case Report

An 86-year-old woman with a history of right breast cancer resected seven years ago had a small pulmonary nodule located in left S5. Diagnosis was made by bronchoscopy using the endobronchial ultrasonography-guided sheath (EBUS-GS) method, but a histological diagnosis was not obtained. Wedge resection was performed due to suspicion of a metastatic lesion from breast cancer based on radiological findings. The tumor was subsequently found to be malignant melanoma of the lung. An initial diagnosis of primary melanoma of the lung was made because a melanoma lesion at another site was not seen despite a detailed work up. However, 8 months after surgery, a malignant melanoma appeared at the tip of the right index finger. We rediagnosed the lung lesion as a metastatic malignant melanoma based on the low incidence of primary melanoma of the lung and on the pathological features.