Granulomatous variant of pigmented purpuric dermatosis

Granulomatous Pigmented Purpuric Dermatosis in a Patient with (Inactive) Myasthenia Gravis: A Case Report and Review of the Literature

Granulomatous pigmented purpuric dermatosis (GPPD) is a rare histologic variant of pigmented purpuric dermatosis (PPD) characterized by dermal histiocyte-rich interstitial infiltration with or without granuloma formation in addition to the other typical features of PPD. GPPD was previously observed more frequently to affect Asians and was reported to be associated with dyslipidemia. However, our literature search of 45 documented GPPD cases revealed an increasing prevalence in Caucasians in addition to dyslipidemia and associated autoimmune diseases. To date, etiopathogenesis of GPPD is unknown but may involve dyslipidemia, genetic and immunological factors such as autoimmune dysregulation or a sarcoidal reaction associated with C. acnes. GPPD is usually persistent and recalcitrant to treatments. We report a case of GPPD in a 57-year-old Thai woman with underlying myasthenia gravis who presented with a pruritic eruption on both lower legs. After treatment with 0.05% clobetasol propionate cream and oral colchicine, the lesion improved with marked flattening and disappeared with residual postinflammatory hyperpigmentation. We provide a literature review of the epidemiology, etiopathogenesis, concomitant comorbidities, clinical symptoms, dermatoscopic features, and treatments of GPPD.

Granulomatous pigmented purpuric dermatosis: clinical and histopathologic findings in a series of nine cases

We report the largest series so far of granulomatous pigmented purpuric dermatosis (GPPD), a rare variant of pigmented purpuric dermatoses (PPD). GPPD can cause diagnostic difficulties as it can be mistaken clinically and histopathologically with numerous inflammatory and infectious dermatoses or even cutaneous T-cell lymphoma. We compared the histopathological findings of nine cases of GPPD with a control group consisting of ten randomly selected PPD of other subtypes. GPPD seems to predominantly affect the lower extremities of adult male patients; a clear association with hyperlipidemia or other systemic conditions could not be confirmed. Histopathologically, GPPD is characterized by a dermal histiocyte-rich interstitial infiltrate with or without granuloma formation, thickened capillaries, extravasated erythrocytes and/or hemosiderin deposits. In contrast to other forms of PPD, the inflammatory infiltrate of GPPD can extend to the mid or deep dermis and the admixed lymphocytic infiltrate is mainly composed of CD8+ T-cells. This article is protected by copyright. All rights reserved.