BackgroundPyoderma gangrenosum (PG) is a rare and chronic neutrophilic dermatosis. It is clinically characterized by aseptic ulcerations preferentially located in the lower limbs. Its location in the genital area is unusual and could be a source of diagnostic difficulties. In half of the cases, PG is associated with an underlying disease. The association with Behcet's disease is exceptional.Case presentationWe report an original observation of a patient who presented a vulvar PG which revealed a Behcet's disease.ConclusionThe distinction between these two pathologies was difficult because of the similarity of the cutaneous-mucous lesions on the one hand, and the absence of histological specificity of these two pathologies on the other hand.