Generalized melanosis in metastatic malignant melanoma: The possible role of DOPAquinone metabolites

Generalized melanosis occurs very rarely as a complication of malignant mel anoma, and the pathogenesis of this condition is still unclear. Histologica l examination of pigmented skin and measurements of the DOPAquinone metabol ites 5-S-cysteinyldopa (5-S-CD) and 6-hydroxy-5-methoxyindole-2-carboxylic acid (6H5MI2C) in the patient's serum and urine were carried out. Histologi cal examination revealed basal hyperpigmentation, discrete melanoma cells a nd melanophages around the blood vessels and an unusual melanin deposition within collagen bundles in the dermis. The levels of 5-S-CD and 6H5MI2C wer e dramatically increased both in the patient's serum and urine. The deposit ion of DOPAquinone metabolites secreted by the melanoma cells may contribut e to the unusual melanin deposition within collagen bundles in the affected dermis.