Case Report
Copyright ©2008 The WJG Press and Baishideng. All rights reserved.
World J Gastroenterol. Jul 21, 2008; 14(27): 4389-4394
Published online Jul 21, 2008. doi: 10.3748/wjg.14.4389
Evidence for colorectal sarcomatoid carcinoma arising from tubulovillous adenoma
Jeffrey K Lee, Pradipta Ghosh, Valerie McWhorter, Misty Payne, Ryan Olson, Mary L Krinsky, Sonia Ramamoorthy, John M Carethers
Jeffrey K Lee, Pradipta Ghosh, Mary L Krinsky, John M Carethers, Department of Medicine, University of California; San Diego, California; and Veteran Affairs Medical Center, San Diego Healthcare System, San Diego, California 92093-0063, United States
Valerie McWhorter, Misty Payne, Ryan Olson, Department of Pathology, University of California; San Diego, California; and Veteran Affairs Medical Center, San Diego Healthcare System, San Diego, California 92093-0063, United States
Sonia Ramamoorthy, Department of Surgery, University of California; San Diego, California 92093-0063, United States
Author contributions: Lee JK wrote the manuscript; Ghosh P wrote and corrected the manuscript; McWhorter V, Payne M, Olson R examined the patient biopsies and performed the immunohistochemical staining; Krinsky ML performed the flexible sigmoidoscopy and endoscopic ultrasound and Carethers JM performed the colonoscopy, wrote, and corrected the manuscript.
Correspondence to: John M Carethers, MD, Professor of Medicine and Chief, Division of Gastroenterology, University of California, San Diego UC 303 (MC 0063), 9500 Gilman Drive, La Jolla CA 92093-0063, United States. jcarethers@ucsd.edu
Telephone: +1-858-5343320
Fax: +1-858-5343338
Received: January 3, 2008
Revised: June 17, 2008
Accepted: June 24, 2008
Published online: July 21, 2008
Abstract

Sarcomatoid carcinomas of the colorectum are rare tumors that display both malignant epithelial and stromal components. Clinically, they are aggressive tumors with early metastasis. Due to their infrequent occurrence, the pathogenesis is poorly understood. We report a case of a 52-year-old woman who presented with a rectal mass and intermittent hematochezia. Superficial biopsies during colonoscopy revealed a tubulovillous adenoma with high-grade dysplasia. Endoscopic ultrasonography confirmed an invasive nature of the mass, and deeper biopsies revealed the presence of neoplasm with mixed histological components. The surgically-excised specimen demonstrated the presence of poorly differentiated spindle cells underneath the tubulovillous adenoma and an intermediate stage of invasive adenocarcinoma. Based on the histological appearance and immunohistochemical studies, a diagnosis of sarcomatoid carcinoma was made. Only nine cases of sarcomatoid carcinomas of the colorectum have been reported to date. As a result, the terminology and pathogenesis of sarcomatoid carcinoma remain speculative. To the best of our knowledge, this is the first report of co-existence of sarcomatoid carcinoma and invasive adenocarcinoma with tubulovillous adenoma; all stages represented within the same tumor. This observation supports the “monoclonal theory” of pathogenesis with an adenoma-sarcoma progression with or without an intermediate stage of carcinoma.

Keywords: Sarcomatoid carcinoma; Tubulovillous adenoma; Adenocarcinoma; Rectum; Cytokeratin