Acquired reticulate pigmentation of the flexures developed in ten patients. Additional features in some cases were pitted scars near the angles of the mouth and scattered dark comedone-like lesions on the neck (dark dot follicles). The disease affects both sexes, usually develops in early adult life, and is slowly progressive. The abnormality is characterized by pigmented filiform epidermal downgrowths closely resembling an adenoid seborrheic wart, but similar proliferations also develop around the variably dilated pilosebaceous follicles. The occurence of the anomaly in siblings and in mother and daughter in two families suggests the condition in a new genodermatosis. Reticulate pigmented anomaly of the flexures bears a spurious clinical resemblance to acanthosis nigricans and, thus, the recognition of this new genodermatosis should spare patients undergoing unnecessary investigations to exclude visceral malignancy.