Atypical ulcers.

Atypical ulcers of the skin challenge the dermatologist with respect to recognition, diagnosis, management, and treatment. The entire gamut of pathogenic categories including vascular, inflammatory, neoplastic, genetic, medication-related, and infectious processes may give rise to atypical ulcers. By definition, these ulcers are unusual, and accurate diagnosis may ultimately require the clinician to violate the dictum that "common things are common." Atypical ulcers may present with features that the clinician has not previously encountered, or may present with seemingly typical features that actually mislead due to phenotypic mimicry. Because skin ulcers are inherently tissue-destructive, and may reflect an underlying systemic disease process, there is heightened urgency to achieving an accurate diagnosis and initiating appropriate therapy.