An Unusual Rectal Tumor

Electronic Clinical Challenges and Images in GI An Unusual Rectal Tumor

Question: A 48-year-old woman underwent screening colonoscopy and a 4mm yellowish tumor with intact surface was found in the rectum (Figures A and B). Endoscopic ultrasound examination disclosed a 4mm, well-defined, hypoechoic tumor in the submucosal layer (Figure C). The patient requested to perform endoscopic submucosal dissection for complete removal of the tumor. What is the diagnosis? See the GASTROENTEROLOGY web site (www. gastrojournal.org) for more information on submitting your favorite image to Clinical Challenges and Images in GI.

HUI-TING HSU CHIH-JUNG CHEN Department of Pathology HSU-HENG YEN Department of Gastroenterology Changhua Christian Hospital Changhua, Taiwan

Conflicts of interest The authors disclose no conflicts. © 2010 by the AGA Institute 0016-5085/$36.00 doi:10.1053/j.gastro.2009.11.069

GASTROENTEROLOGY 2010;139:e3– e4

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ELECTRONIC CLINICAL CHALLENGES AND IMAGES IN GI

GASTROENTEROLOGY Vol. 139, No. 5

Answer to the Clinical Challenges and Images in GI Question: Image 2: Localized Lymphoid Hyperplasia of the Rectum Rectal carcinoid tumor was suggested by the colonoscopy. The patient refused biopsy and requested to perform ESD for complete tumor excision (Figure D). Pathologic examination disclosed lymphoid hyperplasia with germinal center formation and marginal zone hyperplasia in the submucosa (Figure E). Localized lymphoid hyperplasia was then diagnosed. Lymphoid hyperplasia is rare in the large intestine. It can be classified into 2 forms: diffuse nodular hyperplasia and localized lymphoid hyperplasia. They are characterized by proliferation of lymphoid tissue in the mucosa or superficial submucosa. Localized lymphoid hyperplasia is most commonly found in the rectum.1 It is also known as rectal tonsil or lymphoid polyps.2 Patients can be asymptomatic or present with anal bleeding. Endoscopically, then are either solitary or confluent of multiple polypoid or submucosal lesions.1,2 The histologic features are also variable, including reactive follicular hyperplasia, progressive transformation of the germinal center, and marginal zone hyperplasia.1 The pathologic differential diagnoses include extranodal marginal zone lymphoma of mucosa associated lymphoid tissue, nodular lymphocyte-predominant Hodgkin lymphoma, follicular lymphoma, and diffuse large B-cell lymphoma.1,2 The etiology of the localized lymphoid hyperplasia is still unclear. Some intestinal pathogens such as Yersinia enterocolitica, Chlamydia trachomatis, and Epstein-Barr virus have been associated with diffuse lymphoid hyperplasia.1,3 In contrast, localized lymphoid hyperplasia may be a sign of the prelymphomatous lesion because monoclonal IgH gene rearrangement by the polymerase chain reaction study was reported.1 Therefore, tumor excision and regular follow-up are warranted in this situation. References 1. Kojima M, Nakamura N, Itoh H, et al. Histological variety of localized lymphoid hyperplasia of the large intestine: histopathological, immunohistochemical and genotypic findings of 16 cases. J Clin Exp Hematop 2009;49:15–21. 2. Farris AB, Lauwers GY, Ferry JA, et al. The rectal tonsil: a reactive lymphoid proliferation that may mimic lymphoma. Am J Surg Pathol 2008;32:1075–1079. 3. Nagaoka S, Bandoh T, Takemura T. Lymphoid hyperplasia of the large intestine: a case report with immunohistochemical and gene analysis. Pathol Int 2000;50:750 –753. For submission instructions, please see the GASTROENTEROLOGY web site (www.gastrojournal.org).