Perforating and granulomatous exogenous ochronosis.

Interestingly, comparison of the histopathologic findings of the annular EO lesions in patients with and without systemic sarcoidosis showed only minor differences.5 In patients with systemic sarcoidosis, the zonal pattern on histopathology was less defined. Only 1 patient had skin lesions outside of the area of EO, but it was not reported whether this patient had systemic sarcoidosis or cutaneous lesions only. Keywords: ochronosis; exogenous; exogenous ochronosis; perforating; granulomatous EN ochronosis exogenous exogenous ochronosis perforating granulomatous 1219 1222 4 09/21/21 20211001 NES 211001 Introduction Exogenous ochronosis (EO) is a cutaneous disorder induced by cosmetic application of skin lightening agents, most commonly hydroquinone.1 The pathogenesis is secondary to inhibition of local activity of homogentisic acid oxidase by hydroquinone, leading to accumulation of homogentisic acid that polymerizes to form ochronotic pigment in the skin. AG-like change in EO has been reported in a patient who presented with annular lesions on a background of severe EO.7 Of note, in AG, elastophagocytosis is a prominent feature, which is absent in actinic granuloma-like EO. [Extracted from the article]