Diagnosis: Ovarian Cancer
The most likely diagnosis is ovarian cancer (Option A), as the clinical triad of ascites, pleural effusion, and an adnexal mass in an older female patient is highly characteristic of advanced ovarian malignancy. 1
Clinical Presentation Analysis
The combination of findings presented creates a classic pattern for ovarian cancer:
- Ascites and pleural effusion are identified by the American College of Radiology as important imaging features in the evaluation of malignant adnexal masses and are key characteristics of ovarian cancer 1
- Pleural effusion in ovarian cancer occurs through peritoneal-pleural communication and lymphatic obstruction, with the right hemithorax being most commonly affected 1
- The International Ovarian Tumor Analysis (IOTA) Simple Rules consider ascites as one of the five key malignant features (M features) that strongly suggest ovarian cancer 1
Why Other Options Are Less Likely
Cervical Cancer (Option B)
- Cervical cancer does not typically present with adnexal masses or pleural effusion as initial manifestations 1
- Cervical cancer spreads primarily by direct extension and lymphatic routes, not by creating adnexal masses with peritoneal dissemination
Endometrial Cancer (Option C)
- Endometrial cancer rarely causes pleural effusion or significant ascites, and would not present with an adnexal mass as the primary finding 1
- Endometrial cancer typically presents with abnormal uterine bleeding and remains confined to the uterus in early stages
Uterine Cancer (Option D)
- Uterine malignancies do not typically present with adnexal masses 1
- Uterine sarcomas or other uterine malignancies would present as uterine masses, not adnexal masses
Diagnostic Approach
The ACR guidelines emphasize that ultrasound imaging features including ascites, pleural effusions, and peritoneal/omental metastases are crucial for evaluating extent of disease in suspected ovarian malignancy 1
Key Ultrasound Features Suggesting Malignancy:
- Complex ovarian mass with both solid and cystic components 2
- Thick or irregular septations 2
- Mural nodules or papillary components 2
- Diameter >5 cm 2
- Ascites or evidence of peritoneal metastases 2
Important Clinical Caveat: Meigs Syndrome
While ovarian cancer is the most likely diagnosis, Meigs syndrome must be considered as a benign differential diagnosis that can mimic ovarian malignancy:
- Meigs syndrome consists of a benign ovarian tumor (typically fibroma, thecoma, or fibrothecoma), ascites, and hydrothorax 3, 4, 5
- CA-125 can be markedly elevated in Meigs syndrome (ranging from 149 IU/mL to 3803 IU/mL in reported cases), mimicking ovarian cancer 3
- Surgery and histopathological examination are necessary to definitively distinguish Meigs syndrome from ovarian malignancy 3, 5
- Meigs syndrome has an excellent prognosis after surgical excision of the mass, with complete resolution of ascites and pleural effusion postoperatively 4, 5
Additional Differential in Endemic Areas:
In countries where tuberculosis is endemic (such as India), pelvic-peritoneal tuberculosis can present identically with complex adnexal masses, ascites, and raised CA-125, especially in peri- and postmenopausal women 6. Ascitic fluid showing lymphocytic predominance, raised ADA level, and absence of malignant cells point toward tuberculosis 6.
Recommended Next Steps
- Transvaginal ultrasound with color Doppler should be the initial imaging modality to characterize the adnexal mass 2, 7
- MRI with IV contrast is recommended if the mass is indeterminate on ultrasound 2
- CT imaging is most useful when extra-ovarian disease is suspected or needs to be ruled out 7
- Surgical exploration with frozen section is ultimately required for definitive diagnosis 7
- Referral to a gynecologic oncologist is critical, as initial management by a gynecologic oncologist is the second most important prognostic factor in long-term survival after stage 2