Granulomatous pigmented purpura: report of a case and review of the literature.

The pigmented purpuric dermatoses (PPD) are a group of diseases characterized by petechiae and bronze discoloration of the skin on the lower extremities. Histopathologically, extravasation of erythrocytes with hemosiderin deposition, a perivascular lymphocytic infiltrate centered on the superficial capillaries and endothelial cell swelling are seen. The granulomatous variant of PPD (GPPD) was described in 1996 and only 10 cases have been reported since in the literature, almost exclusively in patients of East Asian descent only involving the extremities. We present a case of GPPD in a Caucasian, North American Ashkenazi Jewish woman involving the thighs, back, forearms and wrists with concomitant non-granulomatous PPD of the shins. She presented with an asymptomatic, spreading, cayenne pepper-like rash. This rash intermittently involved the lower extremities and back for 15 years, but now involves the thighs with accompanying pink papules on the back, wrists and forearms. Histopathology of the thigh and back lesions revealed superficial lichenoid granulomatous dermatitis with palisading lymphocytes and focal interface changes. Extravasated erythrocytes were seen, but vasculitis was absent. No lymphocytic atypicality was noted and T-cell gene rearrangement studies were non-clonal. This is the second reported case of GPPD in a non-Asian patient and the first case involving sites other than the extremities.