Uterine leiomyoma

Uterine leiomyoma, commonly fibroid, is a very common benign smooth muscle tumour of the uterus.

The more general topic of leiomyoma is covered in the article leiomyoma.

General

• Extremely common... 40% of women by age 40.
• Benign.
  • Can be a cause of abnormal uterine bleeding (commonly abbreviated AUB).
• Large & multiple associated with infertility.
• May be treated medically with a selective progesterone receptor modulator, e.g. ulipristal (Fibristal).

Gross

Feature:

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

Factor 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.

Negatives:

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

Images:

• Fascicular pattern - leiomyosarcoma (WC).

Variants

• Lipoleiomyoma - with adipose tissue.
  • Image: Lipoleiomyoma - low mag. (WC).
• Hypercellular leiomyoma - hypercellularity associated with more mutations.
• Atypical leiomyoma (AKA symplastic leiomyoma) - leiomyoma with nuclear atypia.
  • Image: Atypical leiomyoma (WC).
• Benign metastasizing leiomyoma.
  • This is just what it sounds like. Some believe these are low grade leiomyosarcomas.

IHC

Work-up of suspicious leiomyomas:

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

Others:

• p16 usually -ve.
  • Often +ve in leiomyosarcoma.
• H-caldesmon +ve.

Sign out

Uterine Cervix, Uterus, Bilateral Tubes and IUD, Total Hysterectomy and Bilateral Salpingectomy:
- Uterine leiomyomas.
- Mild atherosclerosis.
- Inactive endometrium.
- Intrauterine device (IUD) - gross only.
- Uterine cervix within normal limits.
- Left uterine tube with small paratubal cyst, negative for 
  significant pathology.
- Right uterine tube with paratubal cyst, negative for significant pathology.
- NEGATIVE for malignancy.

Block letters

UTERUS WITH CERVIX, UTERINE TUBES AND LEFT OVARY, TOTAL HYSTERECTOMY, BILATERAL SALPINGECTOMY 
AND LEFT OOPHRECTOMY:
- LEIOMYOMATA WITH FOCAL CALCIFICATION AND HYALINE CHANGE.
- SECRETORY PHASE ENDOMETRIUM.
- LEFT OVARY WITHIN NORMAL LIMITS.
- UTERINE TUBES WITHIN NORMAL LIMITS.
- UTERINE CERVIX WITHIN NORMAL LIMITS.

Myomectomy

UTERINE MASSES ("FIBROIDS"), MYOMECTOMY:
- LEIOMYOMATA.

UTERINE MASS, HYSTEROSCOPIC MYOMECTOMY:
- BENIGN SMOOTH MUSCLE FRAGMENTS COMPATIBLE WITH LEIOMYOMA.
- SECRETORY PHASE ENDOMETRIUM.

Micro

The sections show bland spindle cells within a fascicular architecture. Hyaline change is present. No necrosis is seen. Mild proliferative activity is seen (~ 2 mitoses/10 HPFs, 1 HPF ~0.2376 mm*mm). No cytologic atypia is apparent.

See also

• Uterine tumours.