Primary hepatic malignant melanoma: a case report.

Primary hepatic malignant melanoma is a very rare disease. In order to provide clues concerning diagnosis, differential diagnosis and pathogenesis of the disease, a case of a 49 year-old female patient with primary hepatic malignant melanoma is presented. B-mode ultrasound and Contrast-enhanced abdominal computerized tomography (CT) examinations revealed that nodules of varying sizes are diffusely distributed in her enlarged liver. Pathological examination revealed that tumor cells with poor differentiation were located in nests with prominent melanin deposition. Immuno-histochemical staining showed that the tumor cells were positive for HMB-45 and S-100 protein. No evidence for primary malignant melanoma of other sites had been found by comprehensive examinations. Therefore, the patient was diagnosed with primary malignant melanoma of liver. Our case showed that primary malignant melanoma of liver is of histological heterogeneity, and immunohistochemical staining may aid in differential diagnosis between it and other hepatic neoplasms.