Leiomyosarcoma

Colon tumor
Mesenchymal tumors
Leiomyosarcoma

Author: Raul S. Gonzalez, M.D. (see Authors page)

Revised: 3 April 2017, last major update March 2017

Copyright: (c) 2003-2017, PathologyOutlines.com, Inc.

PubMed search: colonic leiomyosarcoma

Table of Contents

Cite this page: Leiomyosarcoma. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/colontumorLMS.html. Accessed July 14th, 2017.

Definition / general

Malignant smooth muscle tumor of colon

Essential features

Rare, with poor prognosis
Arises in muscularis propria (Mod Pathol 2015;28 Suppl 1:S47)

Terminology

Most older reports of colonic "leiomyosarcomas" were probably GIST

Epidemiology

Rare in colon; less common than GIST (Am J Surg Pathol 2000;24:1339)

Sites

Small intestine and colon most common GI sites for leiomyosarcoma

Etiology

May be a rare late effect of pelvic radiation (Hepatogastroenterology 2003;50:1933, Am Surg 1999;65:6)

Clinical features

Adult patients often die of disease
Tumors in infants may have more favorable prognosis (J Pediatr Surg 2004;39:1257)

Radiology images

Images hosted on other servers:

Ileocecal lesion

Colon wall thickening

Prognostic factors

Tumor size > 5 cm suggests poor prognosis (Histopathology 2013;63:194)

Treatment

Surgical resection, including of metastases (J Gastrointest Oncol 2015;6:E70)

Gross description

Intraluminal, bulging / polypoid mass measuring up to 25 cm

Gross images

Images hosted on other servers:

Leiomyosarcoma (top) vs. GIST (bottom)

Microscopic (histologic) description

Resembles leiomyosarcoma at other sites: malignant smooth muscle cells with prominent nuclear atypia, coagulative necrosis and at least 1 mitosis per 10 high power fields
Rare examples have osteoclast-like giant cells (Arch Pathol Lab Med 2004;128:440)

Microscopic (histologic) images

Images hosted on PathOut server:

Contributed by Raul S. Gonzalez, M.D.: