Erythema Induratum of Bazin Accompanied by Atrophy of the Subcutaneous Fat

Erythema induratum of Bazin (EIB) is a predominantly lobular panniculitis with or without vasculitis due to Mycobacterium tuberculosis (MTB) infection. Atrophic scars may remain after EIB was healed. Rare cases of EIB showing sharp skin depression may mimic deep morphea and lupus profundus. A rare case of EIB was reported in a 35-year-old female with slightly tender erythematous-violaceous nodules and hyperpigmented depressed scars on both lower legs, resulting in asymmetrical lower leg shape. Histopathological examination showed lobular panniculitis without vasculitis and granulomatous inflammation consisted of caseous necrosis, epithelioid cells, and multinucleated giant cells. Polymerase chain reaction (PCR) from skin biopsy revealed deoxyribonucleic acid (DNA) of MTB. Tuberculin skin test (TST) was positive with a 20-mm induration, and nuclear 99mTc-ethambutol scintigraphy was positive for tuberculosis infection in one-third distal portion of the left lower leg. Clinical improvements were shown after 6 months of antituberculosis therapy. EIB must be considered in patient with erythematous-violaceous nodules on lower leg, especially in endemic areas of tuberculosis infection since diagnosis can be difficult and occasionally, deceptive.