Giant colonic ulcer and pseudopolyps in an immunodepressed patient

We read with interest the case report by Colaiacovo et al. describing a case of disseminated histoplasmosis in an immunodepressed patient [1]. We had a similar case of a 55-year-old African man who was evaluated for leucopenia and a persisting inflammatory syndrome. He had received a cadaveric renal allograft 2 years earlier because of glomerulonephritis, after which he had been treated with an immunosuppressive regimen of prednisone, tacrolimus, and mycophenolate mofetil. He had 1-month history of intermittent rectal bleeding, abdominal pain, and weight loss. Physical examination was unremarkable. Blood, urine, and stool cultures, chest radiograph, and testing for Clostridium difficile toxin, cytomegalovirus (CMV), Epstein–Barr virus, HIV, and parvovirus B19 infection were all negative. Abdominal computed tomography (CT) scan revealed a 5-cm thickened, stenotic segment of the right colon and enlarged mesenteric lymph nodes suggestive of carcinoma ([Fig. 1]).

Fig. 1 Computed tomography scan showed a thickened and stenotic segment of the right colon (arrowhead).

Gastroscopy was normal. Colonoscopy disclosed a 5-cm ulcer ([Fig. 2]) and multiple ulcerated and nonulcerated pseudopolyps of the right colon ([Fig. 3]).

Fig. 2 Giant ulcer of the right colon.

Fig. 3 Ulcerated polypoid lesion with spontaneous bleeding.

Numerous biopsy samples were obtained, including tissue for viral and fungal cultures.

The differential diagnosis in such a case includes Crohn’s disease, ischemic colitis, Behçet’s colitis [2], as well as diseases related to immunodepression: lymphoma, tuberculosis, amebiasis, CMV colitis, histoplasmosis, actinomycosis [3] [4] [5]. Both the samples from the polyps and the biopsies from the ulcer showed a polymorphic inflammatory infiltrate containing some non-necrotizing granulomas ([Fig. 4]) and small oval budding yeast cells within the macrophages compatible with Histoplasma capsulatum ([Fig. 5]).

Fig. 4 Non-necrotizing granulomas within the submucosa (arrowheads) (hematoxylin and eosin, ×200).

Fig. 5 Numerous fungi appearing red with periodic acid Schiff staining (×1000) isolated in the extracellular compartment (arrowhead) and in „grape clusters” within macrophages (arrows). Gomori’s methenamine silver staining showed small uninucleate yeasts, 2 – 4 µm in diameter, some of them with narrow-based buds (arrow) (× 2000, right upper corner).

Extracellular fungi were also noted, suggesting severe infection [5]. After an initial response to liposomal amphotericin B, the patient followed long term maintenance therapy with oral itraconazole. At 4 months, colonoscopy and CT scan were normal. At 1-year follow-up the patient remained asymptomatic.

Gastrointestinal histoplasmosis is usually seen in immunocompromised patients. The symptoms range from none to nausea, vomiting, diarrhea, bleeding, abdominal pain, weight loss, and obstruction. It frequently involves the ileocecal region [3] [6]. Several endoscopic patterns have been described, characterized by: the absence of gross abnormalities; mucosal ulcerations and ulcers; small polyps or plaques; mucosal edema, masses or even strictures leading to perforation [1] [3] [6]. Diagnosis is made by histological examination, culture, detection of serum or urine antigen, and serology testing. Treatment options include amphotericin B or oral itraconazole [3] [5]. In conclusion, disseminated histoplasmosis should be kept in mind in immunodepressed patients with gastrointestinal symptoms.

References

• 1 Colaiacovo R, De Castro A CF, Shiang C et al. Disseminated histoplasmosis: a rare cause of multiple ulcers in the gastrointestinal tract.  Endoscopy. 2011;  43 216
• 2 Kim J S, Lim S H, Choi I J et al. Prediction of the clinical course of Behçet’s colitis according to macroscopic classification by colonoscopy.  Endoscopy. 2000;  32 635-640
• 3 Goulet C J, Moseley R H, Tonnerre C et al. The unturned stone.  N Engl J Med. 2005;  352 489-494
• 4 Fan X, Scott L, Qiu S et al. Colonic coinfection of histoplasma and cytomegalovirus mimicking carcinoma in a patient with HIV/AIDS.  Gastrointest Endosc. 2008;  67 977-978
• 5 Kahi C J, Wheat L J, Allen S D et al. Gastrointestinal histoplasmosis.  Am J Gastroenterol. 2005;  100 220-231
• 6 Hertan H, Nair S, Arguello P. Progressive gastrointestinal histoplasmosis leading to colonic obstruction two years after initial presentation.  Am J Gastroenterol. 2001;  96 221-222