Acute Liver Failure Associated with Diffuse Hepatic Infiltration of Malignant Melanoma of Unknown Primary Origin

An 83-year-old man admitted for left hand pain due to a large necrotic ulcer presented with many sites of erythema on his trunk. Computed tomography revealed multiple poorly marginated masses in the liver; however, no malignant cells were detected on a biopsy of several skin lesions. He died on the 47th hospital day, and autopsy was subsequently performed, showing multiple nodules in the liver. The histological findings revealed clusters of malignant melanoma cells that had diffusely infiltrated the liver parenchyma. No tumor cells were detected in the skin lesions or lymph nodes. Immunohistochemically, the patient was diagnosed to have metastasis from malignant melanoma of unknown origin.