[Exogenous ochronosis: An underdiagnosed cause of acquired facial hyperpigmentation].

Exogenous ochronosis is an acquired dyschromia, most often iatrogenic or cosmetic, resulting from the prolonged use of hydroquinone-containing skin-lightening topicals. Although rare in metropolitan France, it is still observed owing to the persistence of voluntary skin-lightening practices. We report the case of a 57-year-old woman of Central African origin, Fitzpatrick skin type V, with a several-year history of periorbital, temporal and upper-lip hyperpigmentation. The initial reading of the skin biopsy was interpreted as a non-specific histiocytic reaction to exogenous material. Expert review disclosed numerous yellow-brown, round, sickle- or banana-shaped ochronotic bodies deposited in the dermal connective tissue between collagen bundles, without birefringence and with no atypical melanocytic proliferation, establishing the diagnosis of exogenous ochronosis. A repeat history revealed the prolonged use of skin-lightening creams of unknown composition. This case highlights how the diagnosis may be overlooked when the relevant history is not available, and the value of clinicopathological correlation.