Ovarian serous cystadenoma is a common benign epithelial ovarian tumour in middle-aged women, typically appearing on imaging as a unilocular or multilocular cystic mass with thin walls and septations.
Description
Ovarian serous cystadenoma is a benign ovarian neoplasm that originates from the ovarian surface epithelium. It is the most common benign ovarian tumour, typically presenting as a slow-growing, cystic lesion in middle-aged women.
Pathogenesis
Serous cystadenomas are believed to arise from the ovarian surface epithelium, which undergoes a series of genetic and morphological changes resulting in the formation of cystic structures filled with clear, serous fluid.
Subtypes
There are no recognised subtypes of ovarian serous cystadenoma.
Epidemiology, Risk Factors & Associations
- Most common benign ovarian tumour, accounting for 20-25% of all ovarian neoplasms
- Typically affects middle-aged women, but can occur at any age
- No specific risk factors or associations are known.
Clinical Features
- Often asymptomatic and found incidentally
- If large, may cause pelvic pressure or pain, bloating, or urinary symptoms due to mass effect
- Rarely, may be associated with Meigs’ syndrome, which includes ascites and pleural effusion.
Complications
- Potential for torsion, rupture, and haemorrhage, particularly in larger tumours
- Although benign, these tumours can grow quite large and may cause significant morbidity due to their mass effect.
- No recognised risk of malignant transformation into serous cystadenocarcinoma
Pathological Features
Histopathology
- Macroscopic: Usually unilocular or multilocular with thin walls and clear serous fluid.
- Microscopic: Characterised by a single layer of tall, columnar, ciliated cells resembling the fallopian tubes.
Serology
- No specific serological markers
Biochemistry
- No specific biochemical changes
Radiological Features
General Features
- Characteristically demonstrates a unilocular or multilocular cystic mass with thin walls and septations.
- Calcifications are rare.
- The string of pearls sign (multiple small peripheral cysts) may be seen.
CT
- Non-contrast: Shows a well-defined cystic mass. Calcifications are rare.
- Contrast-enhanced: No enhancement of the cystic components, but any septations or nodules may enhance.
MRI
- T1WI: The cystic components are typically low signal.
- T2WI: The cystic components are typically high signal.
- T1 C+: No enhancement of the cystic components, but any septations or nodules may enhance.
US
- B-mode: Shows a well-defined anechoic mass with posterior acoustic enhancement. Thin septations or a string of pearls sign may be seen.
- Colour: No internal vascularity unless complicated by torsion or haemorrhage.
NM
- PET FDG: Typically not FDG-avid due to its benign nature.
Grading and Staging
Not applicable as it is a benign tumour.
Diagnosis
Diagnosis is typically made based on imaging findings and clinical history. Confirmatory diagnosis is made histologically following surgical excision.
Differential Diagnosis
- Mucinous cystadenoma: Often larger, more multilocular and may contain echogenic mucin on ultrasound.
- Cystadenofibroma: Exhibits more solid component on imaging.
- Benign cystic teratoma: Usually shows fat component on CT or MRI and echogenic lines/shadows on ultrasound.
Management
Management typically involves surgical excision. In premenopausal women, surgery may be conservative to preserve fertility, while in postmenopausal women, a more extensive surgery may be performed due to the risk of coexisting malignancy.