From the Guidelines
A patient with papillary thyroid cancer status post lobectomy who has a pelvic mass that appears as a possible cyst on CT abdomen/pelvis should be referred non-urgently to OB/GYN. The specialist can perform a detailed pelvic examination, transvaginal ultrasound for better characterization of the mass, and possibly CA-125 testing to help determine if the cyst is benign or potentially malignant, as suggested by the American College of Radiology appropriateness criteria 1. Most pelvic cysts are benign, especially if they have simple cyst characteristics on imaging (thin-walled, unilocular, no solid components). The OB/GYN may recommend watchful waiting with follow-up imaging in 6-12 weeks if the cyst appears benign, or surgical intervention if there are concerning features.
Key Considerations
- Urgent referral would be necessary only if the patient has acute symptoms like severe pain, signs of rupture, torsion, or if the CT shows complex features highly suspicious for malignancy.
- The thyroid cancer history is likely unrelated to the pelvic finding, as papillary thyroid cancer rarely metastasizes to the pelvis, but the OB/GYN will consider the patient's complete medical history in their evaluation and management plan.
- Initial management by a gynecological oncologist is an important prognostic factor in long-term survival in patients with ovarian malignancy, highlighting the importance of appropriate triage to subspecialty referral 1.
Diagnostic Approach
- Transvaginal ultrasound is an essential component of a pelvic US examination in the female population and can help diagnose adnexal masses as benign, malignant, or indeterminate 1.
- MRI with contrast can also be used for further characterization of the mass, especially if the ultrasound findings are indeterminate or if there are complex features suspicious for malignancy 1.
From the Research
Referral to OB/GYN
The patient with papillary thyroid cancer and a pelvic mass should be referred to an OB/GYN specialist. The referral urgency depends on the suspicion of malignancy and the patient's symptoms.
- If the patient is symptomatic or the mass is suspected to be malignant, an urgent referral is recommended 2.
- If the patient is asymptomatic and the mass is likely benign, a non-urgent referral may be appropriate 3.
Specialist Evaluation
The OB/GYN specialist can evaluate the patient using various diagnostic tools, including:
- Physical examination 4, 5
- Imaging studies such as ultrasound 5 or CT scans
- Laboratory tests, including biomarkers such as CA125 2
- Menopausal status 2
Diagnostic Algorithms
The specialist can use diagnostic algorithms such as the Risk of Malignancy Index (RMI) 2, OVA1 multivariate index 2, or the Risk of Malignancy Algorithm (ROMA) 2 to aid in distinguishing malignant from benign pelvic masses. These algorithms can help inform decisions regarding appropriate referral to a gynecologic oncologist.
Management
The management of the pelvic mass will depend on the diagnosis and the patient's overall health status. The specialist can discuss treatment options with the patient, which may include surgery, observation, or other interventions. If the mass is suspected to be malignant, referral to a gynecologic oncologist may be necessary 6, 2.