Papillon-Lefèvre syndrome (PLS) is a rare autosomal-recessive genodermatosis characterized by palmoplantar hyperkeratosis and severe early-onset periodontitis. The development of malignant cutaneous neoplasms within the hyperkeratotic lesions of the syndrome is quite rare. Here, we report on a 51-year-old Japanese woman with PLS associated with recurrent malignant melanoma (MM). Mutation analysis of the cathepsin C gene revealed that the proband was homozygous for a missense mutation, c.415G-->A, which is predicted to result in the amino acid substitution p.G139R. Including our case, 4 families have been described as having PLS with MM, 3 of which are Japanese, implying a high incidence of melanoma development in Japanese PLS patients. We suggest that hereditary palmoplantar keratoderma (PPK) in Japanese patients might be predisposed to MM. A literature review revealed that in 18 cases of MM-associated PPK, 13 (76%) were Japanese, suggesting a high incidence of MM in Japanese PPK patients. This tendency might be attributable to the high frequency of acral lentiginous melanoma in Japanese subjects, in contrast to a lower frequency of this subtype in Caucasians. Copyright 2008 S. Karger AG, Basel.