Melanocyte stimulation in focal dermal hypoplasia with unusual pigmented skin lesions: a histologic and immunohistochemical study.

Focal dermal hypoplasia (FDH) or Goltz syndrome is a rare genodermatosis transmitted in a dominant, X-linked mode. It is characterized clinically by atrophic skin lesions, multiple mucocutaneous papillomas, hyperpigmented linear skin lesions, and several skeletal and visceral anomalies. We followed over several years a female patient with FDH, who had the characteristic atrophic cutaneous lesions and periorificial papillomas, who developed at the periphery of atrophic lesions peculiar lentigo-like pigmented macules. Immunohistologically, increased melanin deposits within the epidermis and the dermis were seen, produced by stimulated epidermal melanocytes expressing the HMB-45 antigen. These findings further support the contention that cutaneous lesions of FDH may be progressive, and provide a physiopathologic basis for understanding the hyperpigmented lesions of FDH.