Histologic sections showed a central ulceration surrounded by a dense infiltration of histiocytes and lymphocytes. There was an area of caseating necrosis. A Fite stain demonstrated numerous acid-fast bacilli, and a periodic acid–Schiff stain was negative for fungal microorganisms. Another biopsy specimen (not shown) demonstrated pseudocarcinomatous hyperplasia with a suppurative granulomatous infiltrate with multinucleated histiocytes, but the results of a Fite stain were negative. The skin biopsy specimen that was sent for culture yielded Mycobacteria tuberculosis. The organism showed sensitivity to ethambutol hydrochloride, isoniazid, and rifampin but was resistance to streptomycin.
Ulcerated Plaque in a 36-Year-Old Woman—Diagnosis. Arch Dermatol. 2006;142(9):1221-1226. doi:10.1001/archderm.142.9.1221-h