A case of a malignant melanoma with late metastases 16 years after the initial surgery

We report a case of a pulmonary metastasis 16 years after the initial surgery for a malignant melanoma. The patient was a 58-year-old Japanese man. In 1976, he had a pigmented skin lesion with a diameter of 8 mm on his right third finger. He received an amputation of the finger and a dissection of the right axillary. Histological examinations of the tumor revealed a feature of a malignant melanoma with infiltration of the papillary layers of the dermis, 1.5 mm in thickness. The histological subtype was considered to be an acral lentiginous melanoma with a mixed spindle-epithelioid cell pattern. There was no regional lymph node metastasis. In December 1992, when he was 74-years-old, a round tumor in the left lower lung was discovered by chest radiography. In February 1993, he received a left lower lobectomy of the lung. Histological examination revealed a feature of a malignant melanoma with predominantly epithelioid cells and this was considered to be a metastasis from the initial skin lesion. Five months after the lobectomy, he died from a hemorrhage of a metastatic brain tumor. This case indicated the importance of periodic, life-long follow-up in treating malignant melanomas.