Notes: A 30-year-old man, who had originally been admitted to the Centro Dermatológico Pascua for medical attention and was later transferred to the Hospital General de México, presented with a 2-month history of progressive dermatosis affecting the head (face, ear lobes, oral cavity), trunk (all faces), upper and lower limbs (including the palms and soles), external genitalia, and the perianal region. The patient had no history of homosexuality, but did have a long history of sexual intercourse with prostitutes in the city of Ciudad del Carmen (island in southeastern Mexico), where he was born and lives. The dermatosis consisted of multiple nodules and ulcerative lesions, some of them isolated and others with junctions between them, forming verrucous plaques. He complained of mild pruritus and pain. The lesions had first appeared on the face and, over the course of 2 months, had increased in size and number and were accompanied by malaise, fever, and loss of 6 kg of body weight ( 〈link href="#f1"〉Fig. 1). The presumptive clinical diagnosis was leishmaniasis, an endemic disease in the area where he lives. Laboratory parameters at presentation included the following: hemoglobin 11.5 g/dL; hematocrit 34%; white blood cells (WBC) total 7900 cells/mm3 ; lymphocytes total 1414 cells/mm3 ; platelets 449,000/mm3 ; CD4+ lymphocytes 1.5% and CD8+ lymphocytes 81.0%, with a CD4/CD8 ratio of 0.18 cells/mm3. Blood chemistry, hepatic function tests, and serum electrolyte determinations were all within normal ranges. A chest roentgenogram was also normal. Human immunodeficiency virus (HIV) seropositivity was tested by enzyme-linked immunosorbent assay (ELISA) and confirmed by Western blot.〈figure xml:id="f1"〉1〈mediaResource alt="image" href="urn:x-wiley:00119059:IJD877:IJD_877_f1"/〉Initial lesions: nodules, ulcers, and verrucous lesions involving the faceHistologic evaluation showed a dense infiltration of lymphocytes and histiocytes, many of which were markedly vacuolated. A number of intracellular yeast-like cells that were easily stained with hematoxylin and eosin and periodic acid–Schiff (PAS) were evident inside the histiocytes ( 〈link href="#f2"〉Fig. 2). We concluded that the granulomatous process was suggestive of histoplasmosis.〈figure xml:id="f2"〉2〈mediaResource alt="image" href="urn:x-wiley:00119059:IJD877:IJD_877_f2"/〉Histopathology. Higher magnification demonstrated intracellular yeast-like cells of Histoplasma capsulatum inside histiocytes (periodic acid–Schiff stain; ×100) Histoplasma capsulatum was eventually cultured from the skin biopsy specimens. A histoplasmin skin test was negative; precipitin and complement fixation tests using the same antigen were both positive, the latter with an initial titer of 1 : 320.The confirmatory diagnosis of acquired immunodeficiency syndrome (AIDS)-associated cutaneous histoplasmosis prompted us to begin treatment with amphotericin B 1 mg/kg/day, heparin 5 IU/day, hydrocortisone 500 mg/day, and itraconazole 400 mg/day. Also, the main laboratory tests were repeated. When an accumulated dose of 535 mg of amphotericin B had been reached, an elevation of serum creatinine to 1.48 mg/dL occurred, and a glomerular filtration rate of 57.8%, a urinary volume of 1350 mL/24 h, and a potassium (K) of 2.3 mEq/L were found. For this reason, the amphotericin B dose was reduced to 0.50 mg/kg/day, and potassium replacement was started. The reduced amphotericin B dose resulted in an improvement in the serum creatinine to 0.9 mg/dL, a glomerular filtration rate of 92.5%, a urinary volume of 2900 mL/24 h, and a potassium level of 4.3 mEq/L. Despite the abnormalities detected in the laboratory tests, the patient showed a clear clinical improvement and his complement fixation ratio to histoplasmin decreased from 1 : 320 to 1 : 64. Currently, the patient is being maintained with a 300-mg/day dose of itraconazole, and is being periodically re-evaluated by laboratory testing. He shows good clinical progress and resolution of most lesions ( 〈link href="#f3"〉Fig. 3).〈figure xml:id="f3"〉3(a)〈mediaResource alt="image" href="urn:x-wiley:00119059:IJD877:IJD_877_f3"/〉Initial lesions (baseline). (b) After amphotericin B and itraconazole treatment