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 | Differential diagnosis | Additional referencesCite this page: Leiomyoma. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/colontumorleiomyoma.html. Accessed July 14th, 2017.
Definition / general
- Benign smooth muscle proliferation of colon
Essential features
- Benign incidental tumor 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
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
Positive stains
Differential diagnosis
- Gastrointestinal stromal tumor: positive for CD117, arise in muscularis propria (Mod Pathol 2015;28 Suppl 1:S47)
- Leiomyosarcoma: larger, more aggressive / destructive, abundant mitoses, arise in muscularis propria
Additional references









