A Diagnostic Dilemma: Atypical Systemic Pyoderma Gangrenosum.

Pyoderma gangrenosum (PG) is a rare neutrophilic dermatosis that classically presents with chronic ulcerations with raised, violaceous, and undermined borders commonly found on the lower extremities. Less common presentations include tender nodules, pustules, or bullae that may occur on other sites of the body. In rarer circumstances, PG can lead to a systemic inflammatory response syndrome with extensive pulmonary infiltrates but ultimately cause and etiology of the disease are still uncertain. Unfortunately, there is no laboratory test or histopathologic finding that is specific to PG, which makes the diagnosis even more elusive.