Difference between revisions of "Leiomyosarcoma"

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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:

  1. Cellular atypia - common.
  2. Necrosis.
    • Should be patchy/multifocal.
    • Zonal necrosis is suggestive of vascular cause.
  3. Mitoses - key feature.
    • 10 mitoses/HPF.
    • 5 mitoses/HPF - if epithelioid.
    • 2 mitoses/HPF - if myxoid.
    • >=1 mitosis/HPF - if cutaneous.[1]

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. 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.