Galli-Galli Disease Presenting as a Lentigo-like Eruption: A Further Clinical Feature in the Wide Spectrum of Reticulate Pigment Disorders

Dear Editor, Reticulate pigmentary disorders (RPD) is a term used to classify a spectrum of several acquired and congenital disorders. Different clinical features can be present, including a reticular pattern and a freckle-like pattern with hyperor hypo-pigmented macules (1). Dowling-Degos disease (DDD), an autosomal dominant genodermatosis, is the main type of RPD (2). Clinically, DDD presents with pigmented, reticulate, flexural macules and comedo-like papules on the back and neck. Galli-Galli disease (GGD) is a very rare variant of DDD, from which is clinically indistinguishable (3). A 65-year-old Caucasian male patient presented to our Department with a 6-year history of diffuse maculopapular lesions involving the trunk and the extensor and flexor regions of the upper and lower extremities (Figure 1). These lesions were small, monomorphous, erythematous macules and papules, some covered by discrete scales. Numerous brown lentiginous macules were also observed. The patients did not present with comedo-like lesions, reticulate pigmentation, pitted acneiform facial scars, palmar pits, or nail changes. Furthermore, the oral mucosa showed no lesions. The patient’s familial history was negative for dermatoses. Laboratory routine tests were all negative. Topical and oral steroids as well as systemic retinoids were unsuccessful. Therefore, a punch biopsy was performed. Histologic examination showed a digitate elongations of rete ridges, with small foci of acantholysis (Figure 2, a). The epidermis showed a finger-like projections extending into the papillary dermis with increased melanin pigment. The epidermis was atrophic above the digitate proliferations and above the acantholytic foci, where necrotic and dyskeratotic