Colon tumor
Mesenchymal tumors
Leiomyosarcoma




Topic Completed: 01 March 2017

Revised: 15 January 2019, last major update March 2017

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

PubMed search: colonic leiomyosarcoma

Page views in 2018: 669
Page views in 2019 to date: 35
Cite this page: Gonzalez R. Leiomyosarcoma. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/colontumorLMS.html. Accessed January 19th, 2019.
Definition / general
  • Malignant smooth muscle tumor of colon
Essential features
Terminology
  • Most older reports of colonic "leiomyosarcomas" were probably GIST
Epidemiology
Sites
  • Small intestine and colon most common GI sites for leiomyosarcoma
Etiology
Clinical features
Radiology images

Images hosted on other servers:

Ileocecal lesion

Colon wall thickening

Prognostic factors
Treatment
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.:

Colonic leiomyosarcoma

Nuclear atypia

Numerous mitotic figures



Images hosted on other servers:

Well differentiated tumor

Left: moderately differentiated; right: poorly differentiated

Leiomyosarcoma with
osteoclast-like giant cells

Virtual slides
Positive stains
Negative stains
Molecular / cytogenetics description
  • Negative for KIT mutations
Differential diagnosis