Clinical Gastroenterology and Hepatology
Volume 8, Issue 1 , Page A28, January 2010

Cecal Ameboma

published online 12 March 2009.

Article Outline

 

A 60-year-old North Indian man presented with increased bowel frequency and weight loss during a period of 6 weeks. There was no history of rectal bleeding. The patient had not traveled abroad during the past 3 months. Clinical examination was unremarkable. Laboratory investigations were normal. A colonoscopy showed a large ulcerated mass in the cecum (Figure A). Biopsies showed trophozoites of Entamoeba histolytica (within boxes, Figure B), thus confirming the diagnosis of cecal ameboma. The patient completed a 10-day course of oral metronidazole followed by diloxanide furoate. The patient made an uneventful recovery.

Amebiasis is caused by the ingestion of cysts of the protozoan E histolytica in contaminated food or water. More common in developing countries, cases are now being described in the Western world, given the increasing traveling world population. Common sites of infection include the liver and the gastrointestinal tract.

Ameboma refers to the rare development of an inflammatory, ulcerated, exophytic mass in the gastrointestinal tract that can resemble carcinoma.1 Common sites include the cecum, appendix, and rectosigmoid.2 Amebomas occur in untreated or inadequately treated patients usually years after the index case of dysentery. Symptoms include diarrhea, weight loss, and rectal bleeding. Diagnostic tests include polymerase chain reaction techniques for amebic serology and stool exam for microscopy. Endoscopic diagnosis is rare, but common findings include “flask shaped” ulcers covered with white slough.3 Histologic findings include an inflamed mucosal layer with or without the presence of trophozoites and ulceration extending into the submucosa.4 The yield of trophozoites can be further increased by using periodic acid–Schiff or immunoperoxidase and antilectin stains.2 Treatment options include 5–10 days of oral metronidazole followed by diloxanide furoate or paromomycin to eradicate carriage. Follow-up endoscopy is recommended to ensure treatment success.

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References 

  1. Simsek H, Elsurer R, Sokmensuer C, et al. Ameboma mimicking carcinoma of the cecum: case report. Gastrointest Endosc. 2004;59:453–454
  2. Haque R, Huston C, Hughes M, et al. Amebiasis. N Engl J Med. 2003;348:1565–1573
  3. Misra SP, Misra V, Dwivedi M. Ileocecal masses in patients with amebic liver abscess: etiology and management. World J Gastroenterol. 2006;12:1933–1936
  4. Prathap K, Gilman R. The histopathology of acute intestinal amebiasis: a rectal biopsy study. Am J Pathol. 1970;60:229–246

 Conflicts of interest The authors disclose no conflicts.

PII: S1542-3565(09)00195-5

doi:10.1016/j.cgh.2009.02.026

Clinical Gastroenterology and Hepatology
Volume 8, Issue 1 , Page A28, January 2010