Smooth muscle tumor

File:Leiomyoma.jpg

Smooth muscle tumor (in this case leiomyoma).

Author: Mikael Häggström

Comprehensiveness

On this resource, the following formatting is used for comprehensiveness:

• Minimal depth
• (Moderate depth)
• ((Comprehensive))

Gross processing

Gross examination

File:Fibroid locations.jpg

Fibroid locations.

Examine and describe:

• Location. If in the uterus:

• Intramural/submucosal/subserosal (see image)
• (Posterior/anterior/right or left lateral.)

• Number of tumors, if multiple
• Size
• (Presence or absence of any hemorrhage or necrosis.)
• ((Demarcation))

Selection

In case of hysterectomy, submit pieces from all smooth muscle tumors >5 cm in diameter.

Submit any macroscopically abnormal parts of the tumors (hemorrhagic, necrotic, brittle or softening areas, and areas with blurry delimitation).

Microscopic examination

Distinguish leiomyoma (benign) from leiomyosarcoma (malignant) by looking at the latter's criteria:

• Marked cellular atypia
• Mitoses: > 10 mitoses/10 high power fields
• Necrosis

Diagnosis of conventional leiomyosarcoma requires 2 of these 3 histologic features.

• Leiomyomas typically show smooth muscle in a fascicular pattern (arrows point at fascicles).[3][image 1]
  Leiomyomas typically show smooth muscle in a fascicular pattern (arrows point at fascicles).
• Leiomyoma, with areas where the cellularity is relatively lower (left) and higher (right).
  Leiomyoma, with areas where the cellularity is relatively lower (left) and higher (right).
• Leiomyoma with nuclear pleomorphism, yet within benign limits.
  Leiomyoma with nuclear pleomorphism, yet within benign limits.
• Epithelioid leiomyoma
  Epithelioid leiomyoma
• Leiomyoma with palisading pattern
  Leiomyoma with palisading pattern
• Leiomyosarcoma: Variable atypia, often with cytoplasmic vacuoles at both ends of nuclei, and frequent mitoses.[4]
  Leiomyosarcoma: Variable atypia, often with cytoplasmic vacuoles at both ends of nuclei, and frequent mitoses.
• Epithelioid leiomyosarcoma
  Epithelioid leiomyosarcoma

Further information: Evaluation of tumors

Microscopic report

Report:

• Microscopic findings, including any visible linings
• Diagnosis or most probable one
• Any linings or borders.

Example, for a cervical polyp:

File:Histopathology of uterine leiomyoma.jpg File:Uterine leiomyoma with lining.jpg Polyp lined by a single layer of columnar epithelium consistent with endometrium. The interior consists of smooth muscles in a whorled pattern. No atypia. The finding is consistent with a pedunculated submucosal leiomyoma.

  See also: General notes on reporting

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