Case Report
Copyright ©2006 Baishideng Publishing Group Co., Limited. All rights reserved.
World J Gastroenterol. Sep 14, 2006; 12(34): 5569-5572
Published online Sep 14, 2006. doi: 10.3748/wjg.v12.i34.5569
Collision tumor of the rectum: A case report of metastatic gastric adenocarcinoma plus primary rectal adenocarcinoma
Young-Hoon Roh, Hyoun-Wook Lee, Min-Chan Kim, Kyeong-Woo Lee, Mee-Sook Roh
Young-Hoon Roh, Min-Chan Kim, Department of Surgery, Dong-A University College of Medicine, Busan 602-715, South Korea
Hyoun-Wook Lee, Mee-Sook Roh, Department of Pathology, Dong-A University College of Medicine, Busan 602-715, South Korea
Kyeong-Woo Lee, Department of Rehabilitation Medicine, Dong-A University College of Medicine, Busan 602-715, South Korea
Mee-Sook Roh, Medical Research Center for Cancer Molecular Therapy, Dong-A University College of Medicine, Busan 602-715, South Korea
Supported by the Korea Science and Engineering Foundation through the MRCCMT at Dong-A University
Correspondence to: Mee-Sook Roh, MD, PhD, Department of Pathology, Dong-A University College of Medicine 1, 3-ga, Dongdaeshin-dong, Seo-gu, Busan 602-715, Korea. msroh@dau.ac.kr
Telephone: +82-51-2402833 Fax: +82-51-2437396
Received: April 16, 2006
Revised: April 28, 2006
Accepted: May 22, 2006
Published online: September 14, 2006
Abstract

Collision tumors are thought to arise from the accidental meeting and interpenetration of two independent tumors. We report here a highly unusual case of a 61-year old man who had a unique tumor that was composed of a metastatic adenocarcinoma from the stomach to the rectum, which harbored a collision tumor of primary rectal adenocarcinoma. The clonalities of the two histologically distinct lesions of the rectal mass were confirmed by immunohistochemical and molecular analysis. Although histologic examination is the cornerstone in pathology, immunohistochemical and molecular analysis can provide evidence regarding whether tumors originate from the same clone or different clones. To the best of our knowledge, this is the first reported case of such an occurrence.

Keywords: Collision tumor; Rectum; Clonality