Diagnostic Ultrasound - Abdomen and Pelvis

Serous Ovarian Cystadenoma/Carcinoma
TERMINOLOGY
Abbreviations
• Benign or malignant serous tumor
Definitions
• Serous epithelial neoplasm, which can be benign (serous
cystadenoma), borderline (low malignant potential), or
malignant (serous cystadenocarcinoma)
IMAGING
General Features
• Best diagnostic clue
○ Large, thin-walled, unilocular mass ± papillary projections
• Location
○ Bilateral in 25% of benign tumors and 65% of malignant
tumors
• Size
○ Variable but often large
Ultrasonographic Findings
• Grayscale ultrasound
○ Typically unilocular or few septations, even in malignant
tumors
○ Cyst fluid is clear to mildly echogenic
– Usually less echogenic than mucinous counterpart
○ Septa often thin but may be thick, especially in malignant
tumors
○ Papillary projections common
– Does not necessarily indicate malignancy
– Likelihood of malignancy increases with increased
amount of solid components
○ May see ascites and peritoneal implants in metastatic
disease
– Ascites very concerning for metastatic disease
(positive predictive value of 72-80% as sign of
peritoneal metastases)
○ ~ 1/3 have microcalcifications (psammoma bodies) in
primary tumor and peritoneal metastases
– Usually not discernible by ultrasound
• Doppler ultrasound
○ Flow seen in solid components
○ Central flow within mass is more suggestive of
malignancy than peripheral flow
○ Malignant lesions often have increased flow but
quantitative parameters, such as pulsatility index and
resistive index, are not reliable in differentiating benign
from malignant
CT Findings
• Calcifications may be present
• Soft tissue components enhance with contrast
• Study of choice for tumor staging
Imaging Recommendations
• Best imaging tool
○ Ultrasound ideal method for lesion detection and
characterization
– Always use Doppler to evaluate for flow
○ CT preferred for tumor staging
• Protocol advice
○ Evaluate along paracolic gutters and capsule of liver for
possible peritoneal implants
DIFFERENTIAL DIAGNOSIS
Mucinous Cystadenoma/Carcinoma
• Multilocular masses with low-level echoes
Other Epithelial Tumors
• Significant overlap in imaging findings
• All less common than serous tumors
Ovarian Metastases
• Look for upper abdominal malignancy
PATHOLOGY
General Features
• Etiology
○ Not completely understood
○ One theory is "incessant ovulation": Repeated
microtrauma with cellular repair to surface epithelium
– Increased risk: Nulliparity, early menarche, late
menopause (more ovulatory cycles)
– Reduced risk: Multiparity, late menarche, early
menopause, oral contraceptive use (fewer ovulatory
cycles)
○ High-grade serous adenocarcinoma now thought to arise
from epithelium of fimbriated end of fallopian tube
rather than ovary itself
• Genetics
○ Hereditary causes in 5-10% of ovarian cancers
– Low-grade serous adenocarcinoma
□ KRAS, BRAF mutations
– High-grade serous adenocarcinoma
□ P53 mutation
□ BRCA1/BRCA2 (most common)
– Lynch syndrome
• Associated abnormalities
○ May occasionally be hormonally active producing
estrogen
• Ovarian neoplasms
○ Epithelial tumors 60-70% of all tumors: 85-90% of
malignancies
○ Germ cell tumors 15-20% of all tumors: 3-5% of
malignancies
○ Sex cord-stromal tumors 5-10% of all tumors: 2-3% of
malignancies
○ Metastases and lymphoma 5-10% of all tumors: 5-10% of
malignancies
• Methods of spread
○ Intraperitoneal dissemination most common
– Greater omentum, right subphrenic region, and pouch
of Douglas most common sites found at surgery
○ Direct extension into surrounding organs
○ Lymphatic spread to paraaortic and pelvic nodes
○ Hematogenous spread least common
– Liver and lung most common sites
Staging, Grading, & Classification
• FIGO staging system of ovarian carcinoma
○ Stage I: Tumor limited to ovaries
Diagnoses: Female Pelvis
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