Stomach
Other tumors
Leiomyosarcoma
Author: Raul S. Gonzalez, M.D.
Topic Completed: 17 February 2021
Minor changes: 24 February 2021
Copyright: 2017-2021, PathologyOutlines.com, Inc.
PubMed Search: leiomyosarcoma[title] stomach review[ptyp]
Table of Contents
Definition / general | Essential features | Epidemiology | Sites | Clinical features | Prognostic factors | Case reports | Gross images | Microscopic (histologic) description | Microscopic (histologic) images | Positive stains | Negative stains | Sample pathology report | Differential diagnosis | Board review style question #1 | Board review style answer #1Cite this page: Gonzalez RS. Leiomyosarcoma. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/stomachleiomyosarcoma.html. Accessed May 6th, 2021.
Definition / general
- Malignant smooth muscle sarcoma that arises from the muscularis propria of the stomach
- Accounts for 1% of all malignant tumors of the stomach
Essential features
- Rare malignant neoplasm with atypia, mitoses and necrosis histologically
- Positive for SMA and desmin
- Intermediate to poor prognosis
Epidemiology
- Mainly middle aged men (Kathmandu Univ Med J 2006;4:510)
Sites
- Upper part of the body or the fundus of the stomach (Kathmandu Univ Med J 2006;4:510)
Clinical features
- Patients typically present with peptic ulcer-like symptoms, though gastric outlet obstruction may occur (BMC Res Notes 2014;7:479)
- 5 year survival rate is approximately 50% (Histopathology 2013;63:194)
Prognostic factors
- Size of 5 cm or greater is a poor prognostic factor (Histopathology 2013;63:194)
Case reports
- 50 year old woman with hypertension and diabetes presented with a submucosal gastric mass (Case #438)
Gross images
Images hosted on other servers:
Large gastric leiomyosarcoma (> 8 cm)
Microscopic (histologic) description
- Composed of spindle cells with elongated nuclei and eosinophilic fibrillary cytoplasm arranged in fascicles
- Prominent atypia with enlarged, hyperchromatic and pleomorphic nuclei is seen with brisk mitotic activity and areas of necrosis (Odze and Goldblum: Surgical Pathology of the GI Tract, Liver, Biliary tract, and Pancreas, 3rd Edition, 2015)
Microscopic (histologic) images
Contributed by Raul S. Gonzalez, M.D.
Leiomyosarcoma
Case #438
H&E
SMA
MSA
Desmin
Ki67
Sample pathology report
- Stomach, antrum, resection:
- Leiomyosarcoma (6.4 cm) (see comment)
- Margins of resection unremarkable.
- Two benign lymph nodes.
- Comment: The tumor shows prominent nuclear atypia, numerous mitotic figures and regions of necrosis. Immunohistochemical stains for SMA and desmin are positive in the tumor. Leiomyosarcomas are rare in the stomach and risk factors for progression in this location remain poorly defined.
Differential diagnosis
- Gastrointestinal stromal tumor (GIST):
- Leiomyoma:
- Very bland; no atypia or mitotic figures
- Schwannoma:
- Positive for S100
Board review style question #1
Which of the following is a poor prognostic indicator for leiomyosarcoma of the stomach?
- Greater than 20 mitoses per 10 high power fields
- Ki67 proliferative index above 50%
- Size greater than 5 cm
- Tumor necrosis
Board review style answer #1
