Disseminated histoplasmosis

Case contributed by Adrià Roset Altadill
Diagnosis certain

Presentation

Abdominal pain and fever, chronic diarrhea and weight loss in a South American patient on leflunomide and infliximab for rheumatoid arthritis.

Patient Data

Age: 30 years
Gender: Male

Chest CT

ct

Innumerable tiny pulmonary micronodules (<3mm) in a bilateral and random distribution, being slightly more prominent in the upper lobes.

Small calcified nodule in the middle lobe.

Abdominal CT

ct

Mural thickening of the splenic colonic flexure and a proximal jejunal loop with adjacent fat stranding and small pockets of free fluid. Mural hyperenhancement of the cecum.

Multiple reactive mesenteric lymph nodes.

Minimal pelvic free fluid.

Case Discussion

The miliary pattern in the lungs raised a differential diagnosis between metastases, infection, pneumoconioses and sarcoidosis. A transbronchial cryobiopsy was performed, and the histological analysis showed multiple necrotizing granulomas with negative Ziehl-Neelsen stain.

The abdominal CT findings suggested an inflammatory or infectious bowel disease with multisegment involvement. The left colitis eventually led to perforation, and subtotal colectomy was performed. Biopsy specimens of the transverse colon and the cecum demonstrated a necrotizing granulomatous colitis, along with multiple structures in keeping with fungal spores (positive PAS and Grocott stains).

Positive PCR for Histoplasma capsulatum later confirmed the diagnosis of disseminated histoplasmosis. Consolidation treatment with itraconazole was initiated after previous induction with Amphotericin B.

Progressive disseminated histoplasmosis is generally seen in immunosuppressed patients. In this case, the patient was taking leflunomide (an immunosuppressive medication) and infliximab (a biologic factor that interferes with the action of tumor necrosis factor α) for rheumatoid arthritis. Both medications have been linked with an increased risk of this infection 1,2.

Case courtesy of Dra. Noemí Cañete

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