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Table of Contents
Definition / general | Epidemiology | Clinical features | Prognostic factors | Treatment | Gross description | Gross images | Microscopic (histologic) description | Microscopic (histologic) images | Positive stains | Negative stains | Molecular / cytogenetics description | Differential diagnosisCite this page: Leiomyosarcoma. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/uteruslms.html. Accessed July 16th, 2017.
Definition / general
- 1% - 2% of uterine malignancies, but most common uterine sarcoma
- Probably not derived from leiomyomas
Epidemiology
- 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
Treatment
- 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
- Smooth muscle actin, myosin, desmin
- Ki67, ER, PR, EMA
- h-caldesmon (variable, Am J Surg Pathol 2001;25:253), keratin (epithelioid tumors), p53, focal CD10, histone deacetylase 8 (HDCA8), androgen receptor (variable), and c-KIT (variable)
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
- Endometrial stromal sarcoma with smooth muscle metaplasia
- Mitotically active leiomyoma
- Cellular leiomyoma
- Hemorrhagic leiomyoma and hormone induced changes
- Leiomyoma with bizarre nuclei (atypical leiomyoma)
- Myxoid leiomyoma
- Epithelioid leiomyoma
- Leiomyoma with massive lymphoid infiltration
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