Two cases of lung metastasis of malignant melanoma

We report 2 cases of lung metastasis of malignant melanoma. Patient 1 was a 71-year-old woman who had undergone an operation for enucleation of her left eye 13 years earlier. Chest magnetic resonance imaging (MRI) demonstrated intermediate intensity including partially high intensity on T 1 weighted images, and high intensity including partially low intensity on T 2 weighted images. Microscopic findings from a transbronchial lung biopsy specimen disclosed melanotic melanoma. Patient 2 was a 54-year-old man who had undergone surgery for malignant melanoma in the left upper arm 4 years earlier. Chest MRI films demonstrated low intensity on T 1 weighted images, and high intensity on T 2 weighted images. Microscopic findings from specimens of the primary lesion in the left upper arm revealed melanotic melanoma, but the findings from the lower right lobectomy disclosed amelanotic melanoma. It has been reported that MRI is useful in the diagnosis of malignant melanoma, and that melanin content reflects MRI signal intensity. The MRI findings were consistent with the histopathologic findings in each of the 2 cases we reported.