Difference between revisions of "Leiomyosarcoma"
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*Leiomyosarcoma ''de facto'' trumps other sarcomas.<ref name=pmid22833086/> | *Leiomyosarcoma ''de facto'' trumps other sarcomas.<ref name=pmid22833086/> | ||
DDx: | |||
*[[Pleomorphic undifferentiated sarcoma]]. | |||
*[[EBV-associated smooth muscle tumour]] - rare, immunoincompetent individuals. | |||
*[[Carcinosarcoma]]. | |||
*[[Smooth muscle tumour of uncertain malignant potential]] (STUMP). | |||
Images: | Images: | ||
Revision as of 03:26, 4 March 2013
Leiomyosarcoma is a malignant tumour of smooth muscle. It is seen in various places including the uterus and skin.
General
- Poor prognosis.
- Do not (generally) arise from leiomyomas.
- Often singular, i.e. one tumour; unlike leiomyomas (which are often multiple).
Gross
Features:
- "Fleshy" appearance.
- Necrosis.
- Large size.
- Often singular, i.e. one lesion; leiomyomata are often multiple.
Microscopic
Features:
- Usually a cellular lesion.
- Fasciclar arrangement:
- Whorled look at low power.
- Groups of spindle cells cut peripendicular to their long axis adjacent to groups of spindle cells cut in the plane of their long axis.
- Features of malignancy (need all three):
- Nuclear atypia.
- Tumour cell necrosis.
- Should be patchy/multifocal.
- Zonal necrosis is suggestive of vascular cause.
- Should be patchy/multifocal.
- Mitoses - key feature - definitions suffer from HPFitis:
- +/-Heterologous elements, e.g. malignant cartilage or bone.[3]
Notes:
- Leiomyosarcoma de facto trumps other sarcomas.[3]
DDx:
- Pleomorphic undifferentiated sarcoma.
- EBV-associated smooth muscle tumour - rare, immunoincompetent individuals.
- Carcinosarcoma.
- Smooth muscle tumour of uncertain malignant potential (STUMP).
Images:
- Uterine:
- Cutaneous:
Subtypes
Major variants:[4]
- Spindled leiomyosarcoma (leiomyosarcoma NOS) - see above.
- Epithelioid leiomyosarcoma.
- Myxoid leiomyosarcoma.
Minor variants:[4]
- Leiomyosarcoma with prominent intravascular growth.
- Leiomyosarcoma with osteoclast-type cells.
- Leiomyosarcoma with clear cells.
- Leiomyosarcoma with xanthoma-type cells.
Epithelioid leiomyosarcoma
Features:[1]
- >50% epithelial appearance.
- >=5 mitoses/HPF - definition suffers from HPFitis.
Image:
Myxoid leiomyosarcoma
Features:[1]
- >=2 mitoses/HPF - definition suffers from HPFitis.
- May have minimal nuclear atypia.
IHC
Features:
- Positive for SMC markers.
- Desmin - present in all three types of muscle.
- H-caldesmon.
- Smooth muscle myosin.
- CD10 -ve.
- May be +ve.[4]
- Some use in the context of uterine lesions -- CD10 +ve in endometrial stromal sarcoma.
Others:[4]
- ER, PR, AR +ve -- 30-40% of the time.
- CD117 +ve/-ve.
- p53 +ve.
- MIB1 high.
- Kertins usu. -ve -- more often +ve in epithelioid variant.
See also
References
- ↑ 1.0 1.1 1.2 1.3 1.4 Nucci, Marisa R.; Oliva, Esther (2009). Gynecologic Pathology: A Volume in Foundations in Diagnostic Pathology Series (1st ed.). Churchill Livingstone. pp. 281. ISBN 978-0443069208.
- ↑ Kraft S, Fletcher CD (April 2011). "Atypical intradermal smooth muscle neoplasms: clinicopathologic analysis of 84 cases and a reappraisal of cutaneous "leiomyosarcoma"". Am. J. Surg. Pathol. 35 (4): 599–607. doi:10.1097/PAS.0b013e31820e6093. PMID 21358302.
- ↑ 3.0 3.1 Anh Tran, T.; Holloway, RW. (Sep 2012). "Metastatic leiomyosarcoma of the uterus with heterologous differentiation to malignant mesenchymoma.". Int J Gynecol Pathol 31 (5): 453-7. doi:10.1097/PGP.0b013e318246977d. PMID 22833086.
- ↑ 4.0 4.1 4.2 4.3 Nucci, Marisa R.; Oliva, Esther (2009). Gynecologic Pathology: A Volume in Foundations in Diagnostic Pathology Series (1st ed.). Churchill Livingstone. pp. 284. ISBN 978-0443069208.