Bowen's disease of the umbilicus simulating psoriasis vulgaris.

Bowen's disease and other primary cutaneous malignancies are uncommon in patients with psoriasis. Primary malignancies of the umbilicus are also unusual. Plaques of psoriasis and Bowen's disease may appear morphologically similar, requiring examination of a biopsy specimen for definitive diagnosis. We report on a patient with psoriasis who experienced Bowen's disease of the umbilicus that was initially believed to be psoriasis.