Granulomatous Pigmented Purpura: An Unusual Histological Variant

Abstract

Pigmented purpuric dermatoses (PPDs) tend to vary clinically, yet share a similar histology. Granulomas are only rarely seen, with 4 prior reported cases, designated granulomatous pigmented purpura. Historically, granulomatous pigmented purpura has been seen in Asians. In this article, we report the case of a 42-year-old, white female with granulomatous pigmented purpura, the fifth such reported case in the literature. Histopathological examination revealed a granulomatous dermatitis with eosinophils, extravasated erythrocytes, melanophages, and vascular proliferation. These findings were consistently reported on subsequent biopsy 6 months later. This case illustrates a rare histological finding in PPDs. Medications associated with PPD are reviewed and the patient's use of mesalamine and balsalazide for ulcerative colitis are deemed potential triggers, given their relative similarity to aspirin, a known trigger of PPD. Although other granulomatous processes must be excluded in such patients, one must consider the possibility of granulomatous pigmented purpura in the appropriate setting.