Uterine tumours

This article deals with uterine tumours, with the exception of the tumours that arise from the endometrium.

Uterine tumours are like water in the sea - very very common. Many hysterectomies are done for them. The most common are leiomyomata (AKA fibroids).

Pre-malignant endometrium and endometrial tumours are dealt with in the articles, endometrial hyperplasia and endometrial carcinoma.

Common benign

Uterine leiomyoma

Main article: Leiomyoma

• Often called fibroids.
• Fibroid uterus redirects here.

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.

Uncommon benign

Uterine adenofibroma

• AKA adenofibroma of the uterus.

General

• Uncommmon.
• Benign looking lesions can reoccur.
  • It has been proposed that these lesions are in fact well-differentiated adenosarcomas.

Microscopic

Features:

• Moderately demarcated lesion with:
  • Pale stroma and epithelioid/spindle cells.
  • Simple cuboidal (or columnar) epithelium with eosinophilic cytoplasm.
• Low mitotic rate.
• Nuclear atypia minimal.

Note:

• Appearance similar to fibroadenoma.

DDx:

• Adenosarcoma.

Images:

• Adenofibroma of the uterus - low mag. (webpathology.com).
• Adenofibroma of the uterus - high mag. (webpathology.com).

Adenomatoid tumour

Should not be confused with the bone tumour adamantinoma.

Main article: Adenomatoid tumour

Uncertain malignant potential

Smooth muscle tumour of uncertain malignant potential

• Abbreviated STUMP.

Main article: Smooth muscle tumour of uncertain malignant potential

Malignant

Uterine carcinosarcoma

• AKA malignant mixed muellerian tumour, abbreviated MMMT.

Main article: Uterine carcinosarcoma

Adenosarcoma of the uterus

• AKA uterine adenosarcoma.

Main article: Adenosarcoma of the uterus

Uterine leiomyosarcoma

Main article: Leiomyosarcoma

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:

• Smooth muscle differentiation - essential.
  • Fascicular architecture.
    • 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.
  • May rely on IHC - if poorly differentiated.
• Malignant histomorphologic features - two of three required - key features:
  1. Nuclear pleomorphism.
  2. Coagulative tumour cell necrosis
     • Should be patchy/multifocal.
     • Zonal necrosis is suggestive of vascular cause and may be a degenerative change.
       • Zonal necrosis may be seen in (benign) leiomyomas.
  3. Mitoses.
     • 10 mitoses/10 HPF.
     • 5 mitoses/10 HPF - if epithelioid.
     • 2 mitoses/10 HPF - if myxoid.

Note:

• The mitotic rate seems to be a relatively weak predictor; a modest rate may be malignant and a high rate benign.

DDx:

• Endometrial stromal sarcoma.
• Uterine carcinosarcoma.
• Undifferentiated endometrial sarcoma.
• Smooth muscle tumour of uncertain malignant potential.
• Uterine leiomyoma.

IHC

• CD10 -ve.
• Positive for SMC markers.
  • Desmin - present in all three types of muscle.
  • Caldesmon.
  • Smooth muscle myosin.
• p16 +ve.
  • Useful for differentiation from leiomyoma.

Endometrial stromal tumours

This grouping includes the gamut from benign to malignant.

Overview

WHO classification:

• Endometrial stromal nodule - not a tumour.
• Endometrial stromal sarcoma (ESS), low grade.
• Undifferentiated endometrial sarcoma (UES).

Notes:

• Some believe in a "high grade ESS"... some don't.

Endometrial stromal nodule

• Abbreviated ESN.

General

• Benign.

Microscopic

Features:

• Well-circumscribed - key feature.
  • The interface of the lesion may not have more than three finger-like irregularities/projections into the surround myometrium that are >= 3 mm.
    • If it does... it is an ESS.
• No vascular invasion.

DDx:

• Endometrial stromal sarcoma (ESS), UES - myometrial invasion or vascular invasion.

Images:

• ESN (WC).

Endometrial stromal sarcoma

• Abbreviated ESS.
• Previously known as low-grade endometrial stromal sarcoma.

Main article: Endometrial stromal sarcoma

Undifferentiated endometrial sarcoma

• Abbreviated as UES.
• Previously known as high-grade endometrial stromal sarcoma.

General

• Malignant.
• Rare.
• This can be thought of as pleomorphic undifferentiated sarcoma in the uterus.

Microscopic

Features:

1. Marked nuclear atypia.
2. Mitoses+++.
3. Poorly differentiated - key feature
   • Looks nothing like low grade endometrial stromal sarcoma.
   • Negative for smooth muscle markers (to exclude leiomyosarcoma).

Notes:

• Need IHC to diagnose.

DDx:

• Leiomyosarcoma.
• Carcinosarcoma.
• Rhabdomyosarcoma.
• Melanoma.

IHC

Features:

• SMA ~50% +ve.

Typically negative:

• Smooth muscle markers: desmin, h-caldesmon.
• Skeletal muscle markers: Myf4, actin.
• Melanoma: S100, HMB-45.
• GIST: CD117.

Weird stuff

Trophoblastic tumours

• Choriocarcinoma.
• Epithelioid trophoblastic tumour.
• Placental site trophoblastic tumour.

Uterine tumour resembling an ovarian sex cord stromal tumour

• Abbreviated UTROSCT.

Main article: Uterine tumour resembling an ovarian sex cord stromal tumour

Atypical polypoid adenomyoma of the uterus

• Abbreviated APA.
• AKA atypical polypoid adenomyoma.

Main article: Atypical polypoid adenomyoma of the uterus

See also

• Gynecologic pathology.
• Endometrial carcinoma.
• Endometrial hyperplasia.
• Endometrial polyp.