Leiomyosarcoma
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:
- Usu. 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:
Images:
- Uterine:
- Cutaneous:
Subtypes
Variants:[3]
- Spindled leiomyosarcoma (leiomyosarcoma NOS) - see above.
- Epithelioid leiomyosarcoma.
- Myxoid leiomyosarcoma.
- 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.
Myxoid leiomyosarcoma
Features:[1]
- >=2 mitoses/HPF - definition suffers from HPFitis.
- May have minimal nuclear atypia.
IHC
- CD10 -ve (important in the context of uterine lesions -- +ve in endometrial stromal sarcoma).
- Positive for SMC markers.
- Desmin - present in all three types of muscle.
- Caldesmon.
- Smooth muscle myosin.
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.
- ↑ 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.