Colon tumor
Mesenchymal tumors

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

Revised: 21 February 2017, last major update February 2017

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

PubMed Search: Leiomyoma [title] colon

Cite this page: Leiomyoma. website. Accessed February 21st, 2017.
Definition / General
  • Benign smooth muscle proliferation of colon
Essential Features
  • Benign incidental tumor arising in muscularis mucosae
  • Symplastic leiomyomaā€¯ refers to benign tumor with bizarre nuclear atypia and possibly increased mitotic activity
  • Most gastrointestinal tract leiomyomas arise in colon
  • Majority arise in rectosigmoid (Mod Pathol 2001;14:950)
Clinical Features
  • Benign; more common in men; median age is 62 years
  • Generally discovered incidentally during colonoscopy
Case Reports
  • Total excision is adequate treatment
Clinical Images
Images hosted on other servers:

Gross Description
  • 4 mm, usually rectosigmoid, firm, white and well delineated polypoid lesion
Micro Description
  • Well differentiated smooth muscle cells beneath mucosa that obliterates and merges with muscularis mucosa
  • May have significant atypia (symplastic leiomyoma)
  • Usually no mitotic activity, no necrosis
Micro Images

Images hosted on other servers: images:

Leiomyoma of muscularis mucosa

Symplastic leiomyoma

Positive Stains
Negative Stains
Additional References