Familial Progressive Hyperpigmentation, Cutaneous Mastocytosis, and Gastrointestinal Stromal Tumor as Clinical Manifestations of Mutations in the c-KIT Receptor Gene.

BACKGROUND: Familial progressive hyperpigmentation (FPH) is an autosomal dominant disorder characterized by the appearance of hyperpigmented patches on the skin from early infancy that increase in size and number with age.

METHODS: We report the clinical and molecular studies of an 11-year-old boy who had areas of hyperpigmentation since birth that had spread across his body as irregular hyperpigmented macules and papules, and include relevant history in family members.

RESULTS: Affected members of his family shared a mutation in the c-KIT gene. All had progressive hyperpigmentation, in some cases accompanied by gastrointestinal stromal tumors and mastocytoma. There have been few reports of familial progressive hyperpigmentation together with systemic manifestations.

CONCLUSIONS: Molecular analysis of c-KIT should be considered in the presence of FPH with systemic involvement.