4.6 Uterus

Question 1

Uterus anatomy

Answer 1

Usually anteverted and anteflexed (80%); may be hard to see postmenopausal uterus on US
Fallopian tubes and uterine arteries run in broad ligament; tubes (less than 4 mm) not usually seen on US

Question 2

Uterus endometrial thickness and cycle

Answer 2

Normal endometrial thickness: less than 4 mm menstrual, 4-8 mm proliferative (GnRH and FSH; d 4-14), 7-14 mm secretory (progesterone from corpus luteum, d 14-28); measured from hypoechoic to hypoechoic (subendometrial halo)
Dominant follicle visible on US at d 8-12, then rapidly increases in size to 20-24 mm just before ovulation (triggered by LH surge)

Question 3

US findings at time of ovulation (less than 36 hours away)

Answer 3

Decreased echogenicity surrounding follicle
Irregular follicular wall (crenation)
Small echogenic core of tissue projecting into follicle (cumulusoophorus)
Sudden complete collapse of follicle at ovulation, with fluid in pouch of Douglas

Question 4

Indications and contraindications for HSG, complications

Answer 4

Performed days 7-12 menstrual cycle, 4-10 mL 28% water soluble contrast
6 Fr Foley catheter
Indications: Infertility; Recurrent miscarriage; Postoperative following tubal ligation; Preoperative before myomectomy
C/I: pregnant, active pelvic infection, uterine surgery in last 3 days
Normal tubal length 12-14 cm
Doxycycline occasionally given if dilated tubes / adhesions as risk of tubo-ovarian abscess
Complications: Bleeding, infection, contrast reaction, uterine injury

Question 5

Uterine and ovarian MRI

Answer 5

T2W Signal (indistinct postmenopause)
Endometrium - high
Junctional zone - low
Peripheral myometrium - intermediate
Epithelium, mucus - high
Ovary (reproductive) - low stroma, high follicles

Question 6

Congenital Mullerian Duct Anomalies

Answer 6

Prevalence of 2-3%
50% have renal anomalies (ipsilateral agenesis is commonest, renal ectopia
Class I (absent Mullerian ducts; very rare): Agenesis vagina, uterus, uterine tubes
Class II (agenesis / absent unilateral MD): Unicornuate uterus
Class III (lack of MD fusion; abnormal external contour): Uterus didelphys
Class IV (partial MD fusion; abnormal external contour): Bicornuate uterus
Class V (septation; commonest overall anomaly; normal external contour): Fibrous septum - highest incidence of infertility as cannot implant; Complete septate (extends to cervical canal); Partial septate (cavity alone)
Class VI: Arcuate uterus (normal variant)
Class VII: Associated with diethylstilboestrol exposure - causes uterine hypoplasia, T shaped uterus, increased risk clear cell cancer of vagina

Question 7

HSG findings Class V uterine anomalies

Answer 7

Septation; commonest overall anomaly; normal external contour;
HSG: intercornuate distance less than 4 cm, intercornuate angle less than 75 degrees
Fibrous septum - highest incidence of infertility as cannot implant; 
Complete septate (extends to cervical canal); 
Partial septate (cavity alone)

Question 8

Mayer-Rokitansky-Hauser Syndrome

Answer 8

MD dysgenesis with vaginal / uterine agenesis
Normal karyotype and normal secondary sex characteristics
Renal anomalies
Normal ovaries, increased risk endometriosis

Question 9

Causes of female infertility

Answer 9

Ovulatory dysfunction (30-40%): Hyperprolactinaemia (drugs, PRL producing tumours), PCOS
Tubular dysfunction (30-40%): Adhesions, Tubular damage, Endometriosis
Adenomysosis
Leiomyoma

Question 10

Gestational trophoblastic disease - definition, imaging, types

Answer 10

Chorionic tissue that undergoes hydropic change but continues to produce chorionic gonadotrophins
Causes enlarged uterus with multiple small (3-10 mm) anechoic areas in uterine cavity
Types: Hydatidiform mole: Complete (usually) or Partial / incomplete; Chorioadenoma destruens (less than 10%; Locally invasive, nonmetastatic)

Question 11

DDx GTD

Answer 11

Hydropic placental degeneration post incomplete abortion, mxyoid degeneration of fibroid, RPoC, Endometrial proliferative disease

Question 12

Hydatidiform mole complete vs partial, CFs

Answer 12

Complete (majority): Hydropic enlargment of chorionic villi, with multiple vesicles of varying size, rarely associated fetal tissue, causes hyperemesis gravidarum, enlarged uterus, heavy first trimester bleeding ± hydropic placental tissue passed PV, ovarian cysts (theca lutein) common
Partial / incomplete: Dysmorphic fetus (often triploid)

Question 13

Choriocarcinoma - association, imaging

Answer 13

Often but not necessarily post pregnancy, can arise in ovary or testis, no recognisable villous structures with synctial and cytotrophoblasts interspersed between areas of haemorrhage and necrosis
Myometrial invasion ± Haematogenous dissemination to lungs, liver, kidneys, brain and GIT
US: Similar to hydatidiform mole
Theca lutein cysts persisting at 3-4 months post uterine evacuation suggest residual disease

Question 14

Pelvic Inflammatory Disease - cause, CFs, imaging

Answer 14

Multibacterial (STDs including gonoccal, chlamydia, herpes; pregnancy related; secondary to appedicitis / diverticulitis, actinomycosis if IUCD in situ), usually begins as cervicitis, progresses to involve uterine cavity, tubes ± tubal spill, peritonitis and oophoritis
Can lead to adnexal adhesions, tubo-ovarian abscess
Causes discharge, cervical motion tenderness, dyspareunia
US: One third normal, fluid filled uterus, thick echogenic tubes, hydro- / pyosalipnx ± adnexal or Pouch of Douglas collections
CT: Bilateral low attenuation adnexal masses, increased density pelvic fat, thickened uterosacral ligaments, ascites

Question 15

Asherman Syndrome definition

Answer 15

Uterine cavity synechiae due to trauma, infection or D&C; can cause infertility

Question 16

IUCD Complications

Answer 16

Embedding
Perforation
Increased risk PID (x3 risk)
Actinomycosis

Question 17

Uterine TB - HSG, location

Answer 17

Usually involves fallopian tubes
HSG: Almost always bilateral and asymmetrical, flask-shaped dilatation / sacculation of fallopian tubes (due to fimbrial obstruction) ± tubal calcification, with tubal shortening and rigidity; ultimately leads to obliteration of uterine cavity in later disease

Question 18

Endometrial hyperplasia - definition, cause

Answer 18

Overgrowth of normal endometrium due to unopposed persistent oestrogen (infrequent ovulation, exogenous oestrogens, oestrogen-producing ovarian neoplasms, tamoxifen [binds 17-beta oestrogen receptor], obesity, PCOS); low risk of progression to endometrial carcinoma

Question 19

Endometrial polyp - definition, risk of malignancy

Answer 19

Causes bleeding; True polyp vs submucosal fibroid, endometrial carcinoma (10% polyps malignant if postmenopausal)

Question 20

Endometrial carcinoma - frequency, RFs, imaging

Answer 20

Commonest gynaecological malignancy, 85% adenocarcinoma, postmenopausal with unopposed oestrogen risk factors (i.e. nulliparity, failed ovulation, obesity, late menopause)
Thickened endometrial stripe (>8 mm postmenopausal, >15 mm premenopausal), with thinning of inner myometrium suggestive of myometrial invasion (deep invasion if obliteration of hypoechoic layer)
Stage 1 and 2 - confined to uterus; 3 & 4 extrauterine
Metastasis - aortocaval and pelvic LNs, liver, lungs, brain

Question 21

Endometriosis - definition, location, imaging

Answer 21

Due to functioning endometrium outside uterus, usually 25-29 y/o at dx
Causes 20% of laparoscopy for infertility, 24% of pelvic pain, due to haemorrhage / fibrosis / adhesions
Sites:
Ovaries (75%) > Pouch of Douglas (70%) > broad / uterosacral ligaments (35%) > uterus and fallopian tubes > GIT (12-37%, usually rectosigmoid) > urinary tract > chest / soft tissues
Rare (less than1%) malignant transformation, 75% from ovary - usually endometroid carcinoma
Endometrioma (chocolate cyst)

Question 22

Endometrioma imaging features

Answer 22

US: homogenous, hypoechoic / anechoic focal ovarian lesion ± hyperechoic foci in wall (predictive of endometrioma) ± internal echoes, ± sepatations; tend not to resolve on follow up.
MR: Homogeneous high signal on T1W, shading on T2W (dependent layering or signal void), with low signal fibrous wall on T1W and T2W
MR differential (high T1W): Dermoid, mucinous cystic neoplasms (SI less than fat and blood), haemorrhagic masses (but haemorrhagic corpus luteal cysts usually unilocular and unilateral, no shading and resolve with time)

Question 23

Adenomyosis - definition, imaging

Answer 23

Endometrial tissues and stroma in myometrium, causing overgrowth of surrounding smooth muscle
Typically 40-50 y/o, two thirds with menorrhagia, dysmenorrhoea; 5-30% asymptomatic
Diffuse: More common, asymmetric distribution throughout uterus
US: Similar to fibroids but less well defined, shaggy margins, always contiguous with junctional zone, minimal mass effect on cavity
HSG: Outpouchings of contrast into wall
MR: Short axis measurement junctional zone ≥12 mm diagnostic, 8-12 mm indeterminate; Hyperintense T2W 2-4 mm foci in thickened junctional zone, often parallel to endometrial stripe

Question 24

Uterine fibroids - CFs, types

Answer 24

20-40% women, can cause palpable mass, pain, bleeding, infertility, pressure symptoms
May grow during pregnancy as oestrogen dependent, regress after menopause (if enlarging, consider leimyosarcoma)
Types: Subserosal, submucosal (least common but most symptomatic), intramural (commonest)
Coarse dystrophic calcification (25%) is specific finding
Extrauterine: IVC, spermatic cord, Wolffian and Mullerian duct remnants, bladder, stomach, oesophagus

Question 25

Uterine fibroids - imaging

Answer 25

US: 20% normal US, focal hypoechoic masses ± distorted endometrial cavity
CT: same attenuation as myometrium but may show differential enhancement
MR: low signal T2W with well-circumscribed hyperintense rim; may have ‘bridging vessel sign’ if subserosal and exophytic (due to flow voids of uterine artery branches between mass and uterus)

Question 26

Cervical carcinoma - histology, staging

Answer 26

Third most common gynaecological malignancy, usually 35-50 y/o
Usually locally invasive SCC, lymphatic spread to parametrial, obturator and presacral nodes, then internal, external and common iliac nodes; haematogenous spread to liver, lung and bone late in disease.
Staging (FIGO)
I - not always visible on MR
II - extends beyond uterus but to pelvic wall or lower 1/3 of vagina: IIA - vaginal extension, no parametrial invasion; IIB - parametrial invasion
III - extension to lower 1/3 of vagina (IIIA), or pelvic sidewall with hydronephrosis (IIIB)
IV - beyond true pelvis to bladder / rectal mucosa (IVA) or distant metastases (IVB)

Question 27

Cervical cancer - criteria for surgical resection

Answer 27

Stage IIA versus IIB on CT
Irregular / poorly defined margins of lateral cervix
Prominent soft tissue stranding
Obliteration of periuterine fat plane

Question 28

Adenoma Malignum - definition, association

Answer 28

Form of cervical cancer, watery discharge, cluster of enhancing Nabothian cysts
Associated with Peutz Jeghers and Mucinous ovarian carcinoma

Question 29

Gartner’s Duct Cyst - definition, location

Answer 29

Inclusion cyst of Gartner’s duct (mesonephric tubules) lateral to vagina

Question 30

Salpangitis Isthmica Nodosa - definition, association, risk

Answer 30

Diverticula like invaginations of epithelial lining herniating into myosalpinx; often associated with prior PID
Risk x10 of ectopic pregnancy

Question 31

Causes of infertility

Answer 31

Female (70%)
Ovulatory dysfunction (25%)
Tubal problems (25%)
Endometriosis (40%)
Inadequate cervical mucus (5%)
Luteal defects (poor progesterone response) (5%)
Male (30%)

Question 32

US Assessment of ovulation

Answer 32

Early: Multiple cysts grow to 10 mm
Dominant follicle (>14 mm) by day 8-12, 5-10% >2 dominant follicles
Impending ovulation: Thickened follicular lining with thin hypechoic layer surrounding follicle, ±crenation
Post-ovulation: Disappearance of follicle, free fluid in pelvis

Question 33

Ovarian hyperstimulation - definition, CFs

Answer 33

Enlarged ovaries with multiple cysts, begins 3-8 days post beta hCG administration may last 6-8 weeks
Ascites, effusions, DIC, DVT, ectopic pregnancy