Stromal tumors

Topic Completed: 1 August 2011

Revised: 25 February 2019

Copyright: 2002-2017, PathologyOutlines.com, Inc.

PubMed search: leiomyosarcoma [title] uterus

Mohamed Mokhtar Desouki, M.D., Ph.D.
Page views in 2018: 14,549
Page views in 2019 to date: 12,365
Cite this page: Desouki M. Leiomyosarcoma. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/uteruslms.html. Accessed September 18th, 2019.
Definition / general
  • 1% - 2% of uterine malignancies, but most common uterine sarcoma
  • Probably not derived from leiomyomas
  • Peaks at ages 40 - 69 years; mean is 54 years
Clinical features
  • Abnormal vaginal bleeding, palpable mass and pelvic pain
  • Presentation may be related to tumor rupture (hemoperitoneum) or due to extrauterine extension
  • 5 year survival 40%, only 10% if anaplastic; minimal survival if extends beyond uterus
Prognostic factors
  • Very aggressive even when confined to uterus
  • Recurrence rate of 53% to 71%
  • Overall survival rate ranges from 15% to 25% with a median survival of only 10 months
  • Tumor size, tumor grade and stage are major prognostic parameters
  • Total abdominal hysterectomy and debulking of tumor
  • Radiotherapy may be useful
  • Chemotherapy with doxorubicin or docetaxel / gemcitabine is used for advanced or recurrent disease
  • Hormonal treatment in subset of patients
Gross description
  • Bulky fleshy tumor invading into myometrial wall or polypoid tumor projecting into lumen
  • Often hemorrhagic or necrotic
  • Grossly appears invasive / infiltrative
  • Usually 5 cm or more, but NOT multiple
Gross images

Images hosted on other servers:

Various images

Microscopic (histologic) description
  • Hypercellular with spindle cells resembling smooth muscle with moderate to severe pleomorphism
  • Infiltrative border is most helpful feature for diagnosis
  • 10+ mitotic figures per 10 high power fields (HPF) in most mitotically active area with abundant abnormal mitotic figures
  • Don't interpret small pyknotic nuclei from smooth muscle cells as mitoses; use only definitive mitotic figures
  • Coagulative tumor cell necrosis is common
  • Rarely contains osteoclast-like giant cells
  • Epithelioid and myxoid leiomyosarcomas are rare variants with mild nuclear atypia and often < 3 mitotic figures/10 HPF
  • Smooth muscle tumors of uncertain malignant potential (STUMP): tumor cell necrosis in a typical leiomyoma; necrosis of uncertain type with ≥ 10 MF/10 HPFs or marked diffuse atypia; marked diffuse or focal atypia with borderline mitotic counts and necrosis difficult to classify
Microscopic (histologic) images

Images hosted on PathOut server:

Contributed by Dr. Jamie Shutter, George Washington University

Images hosted on other servers:

Giant cells and a few mitotic figures

Various images

With endometrioid carcinoma

Positive stains
Negative stains
Molecular / cytogenetics description
  • p53 mutations and overexpression in 25% - 47%, but not in leiomyomas
  • p16 overexpression
  • Patients with germline mutations of fumarate hydratase have increased risk for uterine leiomyosarcomas and uterine leiomyomas
Differential diagnosis
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