Dyschromatosis Symmetrica Hereditaria of Late Onset?

Dyschromatosis symmetrica hereditaria (DSH), also known as reticulated acropigmentation of Dohi, is an autosomal dominant disease with high penetrance, characterized by hypo- and hyperpigmented macules of varying sizes on the dorsal of the extremities with reticulated pattern. This paper presents a female patient with typical dermatological lesions, but only diagnosed in adulthood. It is necessary to perform differential diagnosis with other pigmentary disorders. This entity is not very common in South America, and the vast majority of cases were described in Japanese population. Since it is a benign disease, it is important to be aware of this diagnosis in order to establish the correct conduct for these patients. 1. Introduction Dyschromatoses are characterized by the presence of hyper- and hypopigmented macules arranged in a reticular pattern. Dyschromatosis symmetric hereditaria (DSH) is a rare genodermatosis, autosomal dominant with high penetrance, with some sporadic reported cases. It is often reported in Japanese patients, but there have been also cases in India, Europe, and South America [1, 2]. After the literature review in PubMed database, this is the fourth case reported in Brazil [3, 4]. 2. Case Report A 40-year-old female patient presented with multiple small hyperchromic and hypochromic macules distributed symmetrically on the dorsum of the hands and feet (Figures 1 and 2). She noted these lesions when she was 26 years old, and they were asymptomatic. Moreover multiple freckle-like pigmented macules were also noted on her face (Figure 3). She denies other comorbidities. Investigation for autoimmune disease and other laboratory findings were negative. Family history was positive with a nephew with similar lesions. Figure 1: Hyper- and hypopigmented macules distributed symmetrically on the dorsum of the hands. Figure 2: Hyper- and hypopigmented macules distributed symmetrically on the dorsum of the feet. Figure 3: Multiple freckle-like pigmented macules on the face. Two different biopsies were performed from hypochromic and hyperchromic areas. From hypochromic lesion, histology demonstrated a compact stratum corneum and discrete acanthosis. Using Fontana Masson staining, hypochromic lesion demonstrated marked decrease, with almost absence, of melanin. On the other hand, the hyperchromic lesion demonstrated an intense pigmentation (Figures 4(a) and 4(b)). Those findings were compatible with the clinical hypothesis of DSH. Figure 4: (a) Histology from hypochromic lesion showing decrease, with almost absence of melanin. (b) Histology from