Diagnostic Ultrasound - Abdomen and Pelvis

Nabothian Cyst
TERMINOLOGY
Synonyms
• Retention cyst
• Cervical cyst
• Ovula nabothi
• Nabothian follicle
Definitions
• Mucus-filled cystic dilatation of endocervical gland
• Tunnel cluster: Type of nabothian cyst characterized by
complex multicystic dilatation of endocervical glands
IMAGING
General Features
• Best diagnostic clue
○ Circumscribed superficial unilocular cyst in wall of cervix
• Location
○ Usually superficial, along endocervical canal or ectocervix
– Superficial cysts visible on speculum exam
○ Anterior, posterior or lateral cervical lip
– Not in cervical canal
○ Deep cysts only visible with imaging
• Size
○ Usually 10-15 mm in diameter
○ Rarely > 4 cm
○ Often multiple
• Morphology
○ May distort endocervical canal
○ Can mimic multicystic mass
○ Can enlarge cervix if large or multiple
Ultrasonographic Findings
• Grayscale ultrasound
○ Simple superficial cervical cystic lesion
– Imperceptible thin wall
– Posterior acoustic enhancement (increased through
transmission)
– Anechoic fluid most common
– Can have proteinaceous debris
□ Diffusely echogenic
– Rare septations
□ More likely multiple cysts than true septations
○ Large nabothian cysts
– Can occupy most of cervix
– Displaces endocervical canal
□ Rare cause of cervical stenosis
– Can mimic cervical os dilatation
□ Confusing in pregnancy
○ Multiple cysts common
– Can obscure endocervical canal
– May mimic adnexal or cervical cystic mass
□ Multiple lateral cysts
□ Identification of separate ovary necessary
• Color Doppler
○ Absence of internal or peripheral flow
MR Findings
• T1WI: Variable, often mildly increased signal intensity
• T2WI: High signal intensity secondary to mucous
• T1WI C+: No enhancement
CT Findings
• NECT: Usually isodense or hypodense to cervix
• CECT: Nonenhancing hypodense cervical lesion
Imaging Recommendations
• Best imaging tool
○ TV ultrasound
○ MR helpful for complicated cases
– Intravenous contrast required to differentiate from
neoplasm
– Identify separate ovary
• Protocol advice
○ Identify relationship between nabothian cyst and
endocervical canal
– If fluid in canal, consider alternate diagnosis
○ Debris within cysts is common
– Not associated with malignancy
○ Use color Doppler if cyst appears potentially solid
DIFFERENTIAL DIAGNOSIS
Adenoma Malignum (Minimal Deviation
Adenocarcinoma)
• Low-grade mucinous carcinoma affecting deep
endocervical glands
• Multilocular cystic mass in cervix
• Deeply penetrating into cervical stroma; distinguish from
more superficial nabothian cysts
• Typical clinical presentation of copious watery vaginal
discharge
• Associated with Peutz-Jeghers syndrome
Endocervical Hyperplasia
• Thickening of endocervical mucosa ± cystic change
• Associated with oral progestational agents, pregnancy, and
postpartum
• Appearance can overlap with adenoma malignum
Uterine Cervicitis
• Clinical: Tenacious, yellow or turbid, jelly-like discharge
• Associated with pelvic pressure or discomfort
• Can appear as retention cysts in cervix
Cystic Endometrial Polyp
• May contain cysts and arise from, or prolapse into, cervix
• Endocavitary mass; not within cervical stroma
• Doppler shows flow in stalk
Cervical Cancer
• Bulky large cervix, difficult to identify cervical canal
○ Cervical width > 4 cm
• Solid mass much more common than cystic
• Endometrial fluid from cervical stenosis
• Mucin producing carcinoma can mimic nabothian cyst
○ Both are high signal on T2WI MR
○ Carcinoma enhances irregularly
Cervical Ectopic Pregnancy
• Implantation of conceptus within cervical stroma
• Thick-walled cystic mass
○ Echogenic rim
Diagnoses: Female Pelvis
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