Disseminated histoplasmosis presenting as pyoderma gangrenosum‐like lesions in a patient with acquired immunodeficiency syndrome
Authors: Laochumroonvorapong Pairote , DiCostanzo Damian P. , Wu Hong , Srinivasan Krishnaswamiengar , Abusamieh Mohammed , Levy Howard 
Published: March 2003

A 33‐year‐old Hispanic woman with newly diagnosed human immunodeficiency virus (HIV) infection, a CD4 T‐lymphocyte count of 2, viral load of 730,000 copies/mL, candidal esophagitis, seizure disorder, a history of bacterial pneumonia, and recent weight loss was admitted with tonic clonic seizure. On admission, her vital signs were: pulse of 88, respiration rate of 18, temperature of 37.7 °C, and blood pressure of 126/76. Her only medication was phenytoin. On examination, the patient was found to have multiple umbilicated papules on her face, as well as painful, erythematous, large, punched‐out ulcers on the nose, face, trunk, and extremities of 3 months' duration (Fig. 1). The borders of the ulcers were irregular, raised, boggy, and undermined, while the base contained hemorrhagic exudate partially covered with necrotic eschar. The largest ulcer on the left mandible was 4 cm in diameter. The oral cavity was clear. Because of her subtherapeutic phenytoin level, the medication dose was adjusted, and she was empirically treated with Unasyn for presumptive bacterial infection. Chest radiograph and head computed tomography (CT) scan were within normal limits. Sputum for acid‐fast bacilli (AFB) smear was negative. Serologic studies, including Histoplasma antibodies, toxoplasmosis immunoglobulin M (IgM), rapid plasma reagin (RPR), hepatitis C virus (HCV), and hepatitis B virus (HBV) antibodies were all negative. Examination of the cerebrospinal fluid was within normal limits without the presence of cryptococcal antigen. Blood and cerebrospinal cultures for bacteria, mycobacteria, and fungi were all negative. Viral culture from one of the lesions was also negative. The analysis of her complete blood count showed: white blood count, 2300/μL; hemoglobin, 8.5 g/dL; hematocrit, 25.7%; and platelets, 114,000/μL.

Disseminated histoplasmosis presenting as pyoderma gangrenosum‐like lesions

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Two days after admission, the dermatology service was asked to evaluate the patient. Although the umbilicated papules on the patient's face resembled lesions of molluscum contagiosum, other infectious processes considered in the differential diagnosis included histoplasmosis, cryptococcosis, and Penicillium marnefei. In addition, the morphology of the ulcers, particularly that on the left mandible, resembled lesions of pyoderma gangrenosum. A skin biopsy was performed on an ulcer on the chest. Histopathologic examination revealed granulomatous dermatitis with multiple budding yeast forms, predominantly within histiocytes, with few organisms residing extracellularly. Methenamine silver stain confirmed the presence of 2–4 μm fungal spores suggestive of Histoplasma capsulatum (Fig. 2). Because of the patient's deteriorating condition, intravenous amphotericin B was initiated after tissue culture was obtained. Within the first week of treatment, the skin lesions started to resolve. Histoplasma capsulatum was later isolated by culture, confirming the diagnosis. The patient was continued on amphotericin B for a total of 10 weeks, and was started on lamivudine, stavudine, and nelfinavir for her HIV infection during hospitalization. After amphotericin B therapy, the patient was placed on life‐long suppressive therapy with itraconazole. Follow‐up at 9 months after the initial presentation revealed no evidence of relapse of histoplasmosis.

Biopsy from a chest lesion demonstrating multiple intracellular H. capsulatum. (a) Haematoxylin and eosin; (b) methenamine silver stain (original magnification, × 100)

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