Histologic examination revealed a dense dermal infiltrate composed predominantly of histiocytes and lymphocytes with scattered plasma cells forming, in areas, an ill-defined granulomatous component. Within histiocytes, there were occasional intracytoplasmic 2- to 4-µm organisms consistent with Leishmania species (Figure 3). A computed tomographic scan revealed a left lower thoracic lymphatic cord and a 2.5-cm left inguinal lymph node. Culture on Novy-MacNeal-Nicolle medium from the Centers for Disease Control and Prevention confirmed the species as Leishmania viannia panamensis (formerly known as Leishmania braziliensis panamensis).

Our patient received 3 days of treatment with liposome-encapsulated amphotericin B before therapy with the pentavalent ammonial compound sodium stibogluconate (Pentostam) was initiated, with the intent to treat at a dosage of 1600 mg/d for 20 days. A response to treatment was evident by day 4 of the sodium stibogluconate therapy, with a decrease in the erythema and induration of the skin lesions. The lymphatic cord also was diminished. The patient's therapy was complicated by a transaminitis and was discontinued after 7 doses. After 8 days, the sodium stibogluconate therapy was restarted at a reduced dosage of 800 mg/d but was again discontinued after a total of 17 doses because of a persistent increase in transaminase levels.