[A case of rapidly progressive metastatic pulmonary amelanotic malignant melanoma 16 years after resection of melanoma]
An 80-year-old Japanese male was admitted to our hospital because of bloody sputum. He had a history of malignant melanoma of the left fourth digit, which was surgically excised 16 years previously. On hospital admission, chest computed tomography revealed several nodules in the lower lobes. He underwent thoracoscopic lung biopsy and amelanotic malignant melanoma was histologically diagnosed by immunohistochemical staining. The staining pattern with several antibodies was similar to that of the melanoma excised 16 years previously. Therefore, we concluded that the nodules in the lung were metastases of the malignant melanoma of the digit. Despite treatment with interferon, the nodules progressed rapidly, and the patient died 4 months later. This case suggests that the risk of recurrence with rapidly progressive distant metastasis should be considered in patients with malignant melanoma, even after a long disease-free interval. In addition, this case suggests that immunohistochemical stains with several antibodies are useful in the diagnosis of malignant melanoma.