Malignant melanoma of the chest wall with an unknown primary lesion

We report herein the case of a 66-year-old man who underwent resection and reconstruction of the chest wall due to the presence of a malignant melanoma without a detectable primary lesion. The patient was discharged in good condition after receiving chemotherapy but eventually died of multiple bone metastases 2 years after surgery. Throughout the postoperative course, there were no specific symptoms or findings suggesting the presence of a primary lesion. It was considered likely that the primary tumor was resolved by spontaneous regression after chest wall metastasis had been established.