Colon
Mesenchymal tumors
Leiomyoma
Author: Raul S. Gonzalez, M.D.
Last author update: 29 January 2021
Last staff update: 25 November 2022
Copyright: 2003-2023, PathologyOutlines.com, Inc.
PubMed Search: Leiomyoma [title] colon
Table of Contents
Definition / general | Essential features | Terminology | Sites | Clinical features | Diagnosis | Case reports | Treatment | Clinical images | Gross description | Microscopic (histologic) description | Microscopic (histologic) images | Positive stains | Negative stains | Sample pathology report | Differential diagnosis | Additional references | Board review style question #1 | Board review style answer #1Cite this page: Gonzalez RS. Leiomyoma. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/colontumorleiomyoma.html. Accessed March 28th, 2023.
Definition / general
- Benign smooth muscle proliferation of colon
Essential features
- Benign incidental tumor usually arising in muscularis mucosae
Terminology
- Symplastic leiomyoma refers to benign tumor with bizarre nuclear atypia and possibly increased mitotic activity
Sites
- 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
Diagnosis
- Generally discovered incidentally during colonoscopy
Case reports
- 10 month old girl with leiomyoma of the rectum (Pediatr Surg Int 2003;19:104)
- 54 year old woman with giant retroperitoneal mass (Obstet Gynecol 2003;101:1132)
Treatment
- Total excision is adequate treatment
Clinical images
Images hosted on other servers:
Leiomyoma on colonoscopy
Endoscopic removal of a leiomyoma
Gross description
- Firm, white, well delineated nodule or polyp, generally < 1 cm
Microscopic (histologic) description
- Well differentiated smooth muscle cells with red fibrillar cytoplasm, arranged in fascicles and arising from muscularis mucosae (Arch Pathol Lab Med 2011;135:1311)
- Usually no mitotic activity or necrosis
- Symplastic leiomyomas demonstrate significant atypia and possibly increased mitotic activity
Microscopic (histologic) images
Contributed by Raul S. Gonzalez, M.D. and @Andrew_Fltv on Twitter
Leiomyoma
Symplastic leiomyoma
Leiomyoma
Leiomyoma
Positive stains
Sample pathology report
- Sigmoid colon, polypectomy:
- Leiomyoma
Differential diagnosis
- Gastrointestinal stromal tumor:
- Positive for CD117, arises in muscularis propria (Mod Pathol 2015;28:S47)
- Leiomyosarcoma:
- Larger, more aggressive / destructive, abundant mitoses, arises in muscularis propria
Additional references
Board review style question #1
What is the most common location of origin for leiomyomas of the colon?
- Muscularis mucosae
- Muscularis propria
- Submucosal blood vessels
- Subserosal blood vessels
Board review style answer #1
