A 25-year-old woman with an ulcerative earlobe lesion.

Figure 1. A, Hematoxylin-eosin stain of a skin wedge biopsy specimen obtained from the patient (original magnification, ϫ40) showing pseudo-epitheliomatous hyperplasia and granulomas involving the skin and cartilage. B, Hematoxylin-eosin stain of the skin wedge biopsy specimen (original magnification, ϫ400) showing a noncaseating granuloma. C and D, Photographs of the patient's ear, which demonstrated significant clinical improvement after 3 months of antituberculosis therapy. Diagnosis: cutaneous Mycobacterium tuberculosis infection. A deep-wedge biopsy was performed, and the histopatho-logical evaluation of the skin specimen showed pseudoepithe-liomatous hyperplasia. A significant number of noncaseating granulomas were seen in the cutaneous and subcutaneous tissues (Figure 1A and 1B). Gram stain, fungal stain, and acid-fast bacilli stains had negative findings. Because of the presence of granulomas, a tuberculin skin test (TST) was performed, which resulted in a 30-mm induration. Tissue samples were cultured in Lowenstein-Jensen Middlebrook media, as well as in the liquid culture automated system. Because all of the stains had negative findings and the patient was asymptomatic except for the auricular lesion, antimicrobial drugs were withheld. Four weeks after the third biopsy was performed, the myco-bacterial cultures were reported to be positive for M. tuberculosis. Afterwards, in vitro susceptibility studies determined that the organism was susceptible to isoniazid (minimum in-hibitory concentration [MIC], 0.1 mg/mL), rifampin (MIC, 2.0 mg/mL), ethambutol (MIC, 2.5 mg/mL), and pyrazinamide (MIC, 100 mg/mL). Therapy was initiated with all 4 drugs. Three months after initiation of therapy, the patient was again seen in the clinic. This time, the lesion had already demonstrated significant clinical improvement and resolution of discharge, tenderness, and erythema (Figure 1C and 1D). Extrapulmonary tuberculosis constitutes 10%–12% of all cases of tuberculosis, whereas cutaneous tuberculosis is seen in ∼1.5% of all cases [1–3]. Because cutaneous tuberculosis has a wide spectrum of initial presentations, it is not unusual for the time from presentation to diagnosis to be prolonged. A high index of suspicion among patients who are at high risk can help to direct the appropriate investigations, thereby leading to an early diagnosis and initiation of appropriate treatment. In developed countries, cutaneous M. tuberculosis infection tends to occur among patients who are immunosuppressed because of malignancy, chronic corticosteroid use, or immu-nosuppressive therapy, whereas in developing countries, cuta-neous M. tuberculosis infection occurs more often in the general population [4]. In recent years, however, there has been an increase in the incidence of cutaneous M. tuberculosis infection, especially in regions with higher …