how to assess an ovarian cyst for malignancy? objectives •the normal ovary •types of adnexal...
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Chairman, Division of Clinical Support ServicesSenior consultant radiologist Department of Diagnostic and Interventional ImagingKK Women’s and Children’s Hospital
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How to assess an ovarian cyst for malignancy?<Insert cover image here>
Adj A/Prof Ong Chiou Li
Learning objectives
• The normal ovary
• Types of adnexal masses
• Ultrasound evaluation of adnexal masses
• Features of physiological ovarian structures
and pathology
• Differentiating benign from malignant
Cyclical change in ovaries
• Follicular development
– Follicular phase• Antral follicles 2-4mm
• Dominant follicle 10mm (9-6 days prior to luteal surge)
– Ovulation• 20 – 24mm ( max diameter 15-30mm)
– Luteal phase
• Variation in ovarian volume
6 weeks
Corpus luteum
• Luteal phase
• Wall is slightly thicker and slightly
echogenic
• Hypervascular wall
• May haemorrhage and present with
complex appearances
• May simulate ectopic pregnancy
“Lace-like, fishnet appearance”
-Fibrin strands
Septa
Follow-up
“Solid-looking haemorrhagic cyst”
Functional ovarian “cysts”
• Women of child bearing age
• Usually unilocular and anechoic
• Thin-walled
• Less than 3cm, but can be larger
• Stimulated ovaries
• Resolves with ovulation
• May persist
Left ovary
Ovarian hyperstimulation syndrome
Adnexal masses
• Ovarian
– physiological/pathological
• Non-ovarian
– Uterus
– Bowel
– Lymph nodes
– Tubal
– Urinary tract
– Others – e.g. peritoneal inclusion “cyst”
Ovarian cysts
• Functional “cysts” – cyclical change
• Drugs
• Benign cysts
– Non-neoplastic cysts
– Neoplastic
• Malignant cysts
Seen on Day 2
Ultrasound follow-up
C - Fimbrial cyst
C
Simple cysts
• Up to 10 cm, any age ( risk of malignancy less
than 1%)
• Premenopausal, cysts up to 3cm considered
physiological, no follow-up required
• >3cm up to 5cm, likely benign, no follow-up
• Greater than 5cm, up to 7cm, annual follow-up
• More than 7cm, usually require further imaging
(MRI or surgery)
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Levine et al. Society of Radiologists consensus statement of Radiology 2010
Ultrasound evaluation of adnexal masses
• Location (ovarian / extraovarian)• Size• Morphological assessment
– Wall thickness, septation, internal echoes, solid areas, papillary structures, echogenicity, shadowing
• Colour / spectral Doppler– Colour morphology– Vessel location– Diastolic notch– Analysis of waveforms : RI / PI
Endometrioma
• Predorminantly cystic
• Single or multiloculated
• Diffuse low level echoes or anechoic
• May be associated with hydrosalpinx
Endometriotic cysts
Small dermoid cyst
Mature cystic teratoma
• Benign germ cell tumour
• Usually asymptomatic
• Echogenic contents +/- shadowing
• Echogenic strands and dots
• Fat-fluid level
Ovarian neoplasms
• Epithelial
• Germ cell
• Sex cord-stromal tumours
• Metastases
Epithelial neoplasms
• 60% of all ovarian neoplasms
• 85% of malignant neoplasms are epithelial
• Types of tumours– Serous (50%)
– Mucinous, endometrioid (20% each)
– Clear cell (10%)
– Undifferentiated (<5%)
Mucinous tumour of the ovary
20-year-old with LIF pain Borderline mucinous tumour
35-year-old
Clear cell ca in endometrioticcyst
Non-epithelial tumours
• Germ cell tumours
– Teratomas, dysgerminoma, endodermal sinus
tumours
• Sex cord tumours (1-2% of ovarian
malignancies)
• Metastatic (bowel, breast, melanoma, etc)
Ovarian fibroma
Thickened endometrium in post-
menopausal woman
Hyperplasia, polyps or
neoplasia?
Granulosa cell
tumour
Benign features
• Unilocularity
• Thin wall
• Few septa
• Absence of papillary projections
• Crescent sign1,2
1. Kushtaqi P, Kulkarni KK. SMJ 2008
2. Hillaby K, et al. UOG 2004
Morphological assessment
• 1:178 unilocular cysts ( >40 years) is
malignant.
Malignant cyst contained papillary
excresence.
Granberg et al ’89 (1017 adnexal specimens)
Morphological assessment
• 1.1% incidence of malignancy in simple cysts in
women > 40 years (Osmers et al ’96)
• Unilocular and bilocular cysts – identical risk
• 36% malignancy in multiloculated cysts and those
with complex solid masses (Andolf ’89)
• Risk of malignancy very low for isolated unilocular
simple cysts (Modesitt, 2003, n=2763)
Differentiating benign from malignant
• Solid component
• Central blood flow on colour Doppler
• Abnormal free fluid
• Septation
Hyperechoic structures, no solid component
Brown DL, 1998 (n= 211)
Ultrasound scoring
Malignant ovarian tumours
Degenerated pedunculated fibroid
Usefulness and limitations of Doppler
waveform analysis
• Improves confidence in diagnosis1
• Overlap with inflammatory masses and corpus luteal cysts
• Overlap of indices between benign and malignant masses
• Intraobserver and interobserver variation
1. Valentin, 1999
Risk of malignancy
• Risk of malignancy index1-2
• Scoring systems3-5
• Logistic regression models6
1. Jacobs I 1990, 2. Tingulstad 1996
3. Brown DL 1998, 4. Lerner JP, 1994 5. Sassone AM 1991
6. Holsbeke CV 2007 (IOTA, External validation of mathematical models)
Ten simple rules (International Ovarian tumour analysis, IOTA)
"M" rules "B" rules
M1 Irregular solid tumour B1 Unilocular
M2 Presence of ascites B2 presence of solid components <7mm
M3 At least 4 papillary structures B3Presence of acoustic shadows
M4Irregular multilocular solid tumour, diameter >/= 100mm B4
Smooth multiloculartumour, <100 mm
M5 Very strong blood flow (score 4) B5 No blood flow (score 1)
1. Timmerman et al, UOG 2008 (n=1233 adnexal tumours), IOTA study2. Nunes N, et al, UOG 2014 (validation & meta-analysis), rules applied to 78% of tumours)
Applicable to 76% of tumours (sensitivity =93%, specificity = 90%, LR+: 9.45, LR-:0.08)
Limitations of 10 simple rules
• Rare benign tumours
• Stromal tumours
• Peritoneal inclusion cysts
• Tuboovarian complex (ovarian
abscesses)
• Hydrosalpinx
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CONCLUSION
• Benign ovarian masses outnumber malignant
• Overlap of sonographic appearances
• Efficacy and limitations of colour Doppler
• Use of MRI for problem-solving, workup of masses of uncertain origin, or possibly benign ovarian lesions
• CT for pre-operative staging