Erythema induratum of Bazin.

An 81-year-old woman with a history of renal cell carcinoma and years of slowly, progressively enlarging pulmonary nodules of uncertain etiology presented with several weeks of painful lower extremity nodules. A biopsy revealed changes consistent with nodular vasculitis. A purified protein derivative and QuantiFERON test were positive, favoring the diagnosis of erythema induratum of Bazin. Treatment with a standard four-drug antituberculous regimen resulted in radiographic and clinical improvement. This case emphasizes the importance of dermatologic manifestations in the detection of systemic disease.