Digging into the Histology

A 33-year-old man with ulcerative colitis on immunosuppressive therapy (adalimumab, azathioprine, later switched to tofacitinib) presented with fatigue, fever, bloody diarrhea, and 23 kg weight loss. Clinical deterioration included pancytopenia, reticulonodular lung opacities, and colon perforation, prompting total proctocolectomy and small bowel resection. Histology showed granulomas with yeast forms; fungal stains confirmed Histoplasma capsulatum, supported by positive urine antigen, complement fixation, and clinical context (grain elevator operator in endemic US Midwest). The patient received liposomal amphotericin B induction and oral itraconazole maintenance, resulting in resolution of symptoms and regained weight. Authors emphasize careful reconsideration of colitis etiology in immunosuppressed hosts and histoplasma mimicry of IBD.

A 33-year-old man with ulcerative colitis on immunosuppressive therapy (adalimumab, azathioprine, later switched to tofacitinib) presented with fatigue, fever, bloody diarrhea, and 23 kg weight loss. Clinical deterioration included pancytopenia, reticulonodular lung opacities, and colon perforation, prompting total proctocolectomy and small bowel resection. Histology showed granulomas with yeast forms; fungal stains confirmed Histoplasma capsulatum, supported by positive urine antigen, complement fixation, and clinical context (grain elevator operator in endemic US Midwest). The patient received liposomal amphotericin B induction and oral itraconazole maintenance, resulting in resolution of symptoms and regained weight. Authors emphasize careful reconsideration of colitis etiology in immunosuppressed hosts and histoplasma mimicry of IBD.