Bowen disease is a slowly growing lesion with in situ or intraepithelial atypical squamous cells. This plaque looks like psoriasis.

The diagnosis of Bowen disease is often not made until after biopsy. This plaque looks like actinic keratosis.

Bowen disease of the penis showing a mild pink to red inflammatory patch on the glans; may be confused with psoriasis or lichen planus. If diagnostic doubt exists, confirm with biopsy.