Diagnostic Ultrasound - Abdomen and Pelvis

Endometrial Polyp
TERMINOLOGY
Abbreviations
• Endometrial polyp (EP)
Definitions
• Focal hyperplastic overgrowth of endometrial tissue
• Saline infusion sonohysterography (SHG, SIS): Ultrasound of
uterus after distension of cavity with sterile saline
IMAGING
General Features
• Best diagnostic clue
○ Focal echogenic endometrial thickening or mass with
feeding vessel
• Size
○ Variable: May be tiny or large enough to fill entire uterine
cavity
• Morphology
○ Pedunculated or sessile
– May prolapse into cervical canal
○ Oval or fusiform rather than round
– Round mass more likely to be submucosal fibroid
○ Multiple in 20% of patients
Ultrasonographic Findings
• Grayscale ultrasound
○ Echogenic area in endometrium during proliferative
phase of menstrual cycle
– Proliferative endometrium is normally hypoechoic
– Secretory endometrium is echogenic, may obscure
small polyp
○ Pedunculated or sessile, solitary or multiple
○ Small "cystic" areas within polyp due to dilated
endometrial glands
– Strong correlation with benignity
○ Hyperechoic line sign
– Full/partial echogenic rim around area of endometrial
thickening highly specific for endocavitary mass
– Thought to be compressed endometrium vs. interface
of mass with cavity
– Does not differentiate between masses (polyp vs.
fibroid)
• Color Doppler
○ Single feeding vessel in stalk may be evident
– Divides into smaller vessels within polyp
• 3D
○ Useful for "global view"
○ 3D shows multiple polyps better than 2D
○ Useful during SHG especially if multiple lesions
• Sonohysterography
○ Best technique to differentiate focal from diffuse
endometrial thickening
○ Focal
– Polypoid with thin stalk
– Sessile: If broad-based resection is more complex than
simple snare
○ Diffuse
– Symmetric thickening: "Blind" office biopsy with
Pipelle or similar implement
– Asymmetric: Requires visually directed biopsy of
thickest area
○ Uterine contraction is a response to cavitary distention →
endometrial "wrinkles"
– May be mistaken for sessile polyps
MR Findings
• T2WI
○ Hyperintense, with polyp lower signal intensity than
normal endometrium
– Central fibrous core (low signal intensity) within
endometrial cavity
– Intratumoral cysts (high signal intensity) seen more
frequently in polyps than carcinomas
Imaging Recommendations
• Best imaging tool
○ Transvaginal sonography (TVS), SHG
• Protocol advice
○ TVS
– Schedule scans early in menstrual cycle if possible
□ Endometrium is thin and hypoechoic
– If postmenopausal on hormone replacement therapy
(HRT) schedule immediately after withdrawal bleed
– If postmenopausal not on HRT schedule at any time
○ SHG
– Schedule within first 10 days of menstrual cycle in
menstruating females
□ Avoids risk of displacing an early pregnancy
– Suggest patient take analgesic (nonsteroidal antiinflammatory)
1 hour prior to procedure to minimize
discomfort
○ MR with T2 FS if SHG cannot be performed
• Thick echogenic endometrium in premenopausal female
○ > 15 mm → abnormal → SHG to determine type of biopsy
○ 11-15 mm is indeterminate → follow-up after menstrual
period
○ Normal endometrium will slough post menstrually
○ Persistent thickening of increased echogenicity → SHG
DIFFERENTIAL DIAGNOSIS
Thickened Endometrium
• Endometrial carcinoma
○ Irregular endometrial thickening
○ Often mixed hyper/hypoechoic areas, lack of tumoral
cysts
○ Invasion into myometrium is highly suggestive of
carcinoma
• Endometrial hyperplasia
○ More likely diffuse than focal process
○ Often asymptomatic
Intracavitary Mass
• Submucosal fibroid
○ Hypoechoic mass with shadowing; less echogenic than
endometrial stripe
○ Spherical rather than oval/fusiform
○ Layer of endometrium covers surface of fibroid
○ Disrupts endometrial-myometrial interface
○ Multiple feeding vessels arise from inner myometrium
• Gestational trophoblastic disease
Diagnoses: Female Pelvis
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