Int J Colorectal Dis (2014) 29:887–888 DOI 10.1007/s00384-014-1873-3


Rectal leiomyosarcoma in association with ulcerative colitis: a rare condition with an unusual presentation P. Singh & B. Bello & C. Weber & K. Umanskiy

Accepted: 14 April 2014 / Published online: 29 April 2014 # Springer-Verlag Berlin Heidelberg 2014

Dear Editor: We would like to present to your attention a case of rectal leiomyosarcoma in a patient with long-standing ulcerative colitis (UC) and provide a review of the current literature. Rectal and anal leiomyosarcomas are rare conditions accounting for less than 0.1 % of all colorectal malignancies. Classified as a variant of gastrointestinal sarcoma, leiomyosarcomas of the rectum and anus originate from smooth muscle fibers and carry a considerable malignant potential. To date, only 243 cases of rectal leiomyosarcomas and 18 cases of anal leiomyosarcomas have been reported in the literature contributing to our rather limited understanding on surgical management of this condition. In this report, we describe clinical evaluation, management, and surgical decision making, highlighting the unique aspects of this case as it relates to the diagnosis and management of rectal leiomyosarcoma on a background of long-standing chronic ulcerative colitis. A 70-year-old Caucasian male with a 30-year history of chronic ulcerative colitis presented with a complaint of P. Singh Department of Surgery, The University of Chicago Medicine, 5841 S. Maryland Avenue, MC 6040, Chicago, IL 60637, USA e-mail: [email protected] B. Bello Division of Colon and Rectal Surgery, Sinai Hospital of Baltimore, 2435 W. Belvedere Avenue, Suite 42, Baltimore, MD 21215, USA e-mail: [email protected] C. Weber Department of Pathology, The University of Chicago Medicine, 5841 S. Maryland Avenue, P-310, MC 1089, Chicago, IL 60637, USA e-mail: [email protected] K. Umanskiy (*) Department of Surgery, The University of Chicago Medicine, 5841 South Maryland Ave., MC 5095, Chicago, IL 60637, USA e-mail: [email protected]

constipation and occasional bloody bowel movements. He had been intermittently treated medically for UC and, therefore, initially attributed his symptoms to an acute flare. Over the following 2 months, he progressed to have small-caliber, and occasionally pellet-sized, bowel movements. Initial colonoscopic evaluation demonstrated proctosigmoiditis, but no mass lesions. Several weeks later, however, the patient passed a 1-cm smooth, black mass per rectum that he later recalled was intermittently protruding from the anus following bowel movements (the patient at that time had attributed it to being a hemorrhoid). Upon microscopic evaluation, this mass was found to be consistent with leiomyosarcoma. Digital and endoscopic evaluation revealed an irregular, rubbery, firm mass on the right anterior aspect of the anorectal ring 3 cm proximal to the anal verge. A 3-D endorectal ultrasound (13 MHz) demonstrated a uT2N0 lesion at the proximal aspect of the anorectal ring and at the right anterior aspect involving the anal sphincter complex. Metastatic workup with CT/PET of the chest, abdomen, and pelvis revealed no evidence of metastatic disease. The patient underwent a laparoscopic, robotic-assisted total proctocolectomy with end ileostomy. His postoperative course was unremarkable, and he was discharged home on postoperative day 7. Gross examination demonstrated a 1.7-cm rubbery polypoid lesion located 1 cm proximal from the dentate line. Final pathology revealed a polypoid low-grade leiomyosarcoma of the distal rectum in a background of active UC with all margins free from tumor and eight lymph nodes, all negative for malignancy. Final pathologic stage was pT1bN0Mx. At the present time, the patient remains well and without any evidence of recurrent disease. Leiomyosarcomas account for 10–20 % of all soft tissue sarcomas and most commonly originate in the uterus, GI tract, and retroperitoneum. Within the GI tract, the stomach is the most common site followed by the small intestine, colon, and rectum. The majority of colorectal sarcomas are leiomyosarcomas; however, they constitute less than 0.1 %


of all colorectal malignancies. The first cases of anorectal leiomyosarcomas were reported in 1908 by Exner. Arising from smooth muscle cells, these tumors have often been placed in the same category as gastrointestinal stromal tumors (GISTs) until approximately two decades ago. The advent of targeted therapies for GISTs has led to the development of further criteria for distinguishing leiomyosarcomas as a separate condition from GIST. Though some overlap continues to exist in the diagnostic criteria for both malignancies, leiomyosarcomas are often diagnosed by immunohistochemically staining for muscle markers such as smooth muscle actin (SMA), muscle-specific actin (MSA), desmin, and h-caldesmon, though these markers are not exclusively specific for leiomyosarcoma. Leiomyosarcomas typically stain negative for GIST markers including CD117, CD34, and DOG1.1 and lack c-KIT and PDGFRA mutations. Pathologic differences between leiomyosarcomas and their benign counterparts, leiomyomas, include size of tumor cells, decrease in amount of stromal fibers, presence of numerous abnormal pathologic mitoses (5 to 20 mitoses per ten highpower fields in the rectum), and pleomorphic nuclei. Since the establishment of these more strict pathologic criteria distinguishing leiomyosarcomas and GISTs, only 11 cases of leiomyosarcomas in the colon and 9 cases in the rectum have been reported in the literature. Surgical management of anorectal leiomyosarcomas remains controversial. Our understanding of the surgical management of gastrointestinal leiomyosarcoma parallels that of the management of retroperitoneal sarcomas with complete surgical resection being the only potential curative treatment. The size of the tumor and the margin status are considered to be independent prognostic factors for local recurrence [1]. The two primary surgical treatment options for anorectal leiomyosarcomas are wide local excision (WLE) and radical surgery by either abdominoperineal resection (APR) or low anterior resection (LAR). Outcomes of radical surgery have been associated with lower local recurrence rates, reported as 19.5 % compared to rates of 67.5 to 86 % with WLE. This difference, however, does not result in improved overall survival or affect the rate of distant metastases. Survival at 5 years remains rather low ranging from 20 to 40 % with the two most important prognostic factors being the size of tumor and degree of differentiation which is in line with retroperitoneal sarcomas [1]. Some authors, therefore, recommend WLE for select patients including those with small tumors (

Rectal leiomyosarcoma in association with ulcerative colitis: a rare condition with an unusual presentation.

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