Metastatic malignant melanoma in both lungs ; a case report

The patient is a 66-year-old woman, whose chest roentgenogram revealed a coin lesion in the right lower lung field. Partial resection of the right lung was performed for metastatic lung tumor. The resected tumor was presumed to be leiomyosarcoma, but the diagnosis was uncertain. Six months later, a chest roentgenogram revealed a similar coin lesion in the left lower lung field. Left S6 segmental resection was performed. Histological examination revealed black pigmentation with the Fontana Masson silver stain in spindle-shaped cells in the resected tumor, so malignant melanoma was diagnosed. The previous metastatic tumor of the right lung was reexamined and finally diagnosed as malignant melanoma. There was no evidence of malignant melanoma in the skin, eyes or genital region. Therefore, a soft palate tumor which had been resected six years ago was considered to have been the primary lesion.