Leiomyoma

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A leiomyoma is a very common benign tumour of smooth muscle. Leiomyomas fit into the soft tissue group of lesions. They are extremely common in the uterus. They may also be seen in the skin.

General

  • Benign.

Cutaneous leiomyomas

  • May be part of Hereditary Leiomyomatosis and Renal Cell Cancer (HLRCC).[1][2]

Uterine leiomyoma

  • Often called "fibroids".
  • Extremely common... 40% of women by age 40.
  • Can be a cause of AUB (abnormal uterine bleeding).
  • Large & multiple leiomyomas are associated with infertility.

Gross

  • Sharply circumscribed.
  • Gray-white.
  • Whorled appearance.

Factors that raise concern for leiomyosarcoma:

  • Haemorrhage.
  • Cystic degeneration.
  • Necrosis.

Microscopic

Features:

  • Spindle cells arranged in fascicles.
    • Fascicular appearance: adjacent groups of cells have their long axis perpendicular to one another; looks somewhat like a braided hair that was cut.
  • Whorled arrangement of cells.

Uncommonly present - see note:

  • Necrosis (low power) - suggestive of leiomyosarcoma.
  • Hypercellularity.
  • Nuclear atypia seen at low power.
  • Few mitoses.

Note:

  • Leiomyosarcoma is diagnosed if all of the following are present: (1) high mitotic rate (dependent on site), (2) marked nuclear atypia (seen at low power), (3) necrosis.

DDx:

Variants

IHC

Work-up of suspicious leiomyomas:[6]

  • CD10 +ve.
  • Ki-67 -ve.
  • SMA +ve.
  • Desmin +ve.

Other stains:

  • H-caldesmon +ve.[7]

See also

References

  1. URL: http://www.ncbi.nlm.nih.gov/books/NBK1252/. Accessed on: 2 September 2011.
  2. URL: http://ccr.cancer.gov/staff/gallery.asp?profileid=12822. Accessed on: 2 September 2011.
  3. Busam, Klaus J. (2009). Dermatopathology: A Volume in the Foundations in Diagnostic Pathology Series (1st ed.). Saunders. pp. 533. ISBN 978-0443066542.
  4. http://www3.interscience.wiley.com/journal/119360394/abstract
  5. Patton, KT.; Cheng, L.; Papavero, V.; Blum, MG.; Yeldandi, AV.; Adley, BP.; Luan, C.; Diaz, LK. et al. (Jan 2006). "Benign metastasizing leiomyoma: clonality, telomere length and clinicopathologic analysis.". Mod Pathol 19 (1): 130-40. doi:10.1038/modpathol.3800504. PMID 16357844. http://www.nature.com/modpathol/journal/v19/n1/full/3800504a.html.
  6. STC. 25 February 2009.
  7. Zámecník, M.; Kascák, P. (Jul 2011). "Uterine leiomyoma with amianthoid-like fibers.". Cesk Patol 47 (3): 125-7. PMID 21887931.