Management of Septated Cyst at Supraglottic Thyroid
Yes, you should order ultrasound-guided fine-needle aspiration biopsy (FNAB) for a septated cyst in the thyroid region, as cystic neck masses carry a non-negligible malignancy risk and should not be assumed benign until definitively diagnosed. 1
Rationale for FNAB in Cystic Thyroid Lesions
Cystic masses require continued evaluation until diagnosis is established. The American Academy of Otolaryngology-Head and Neck Surgery explicitly states that for patients with a neck mass deemed at increased risk for malignancy, clinicians should continue evaluation of patients with a cystic neck mass (as determined by FNA or imaging studies) until a diagnosis is obtained and should not assume that the mass is benign. 1
Key Evidence Supporting FNAB for Cystic Lesions
Ultrasound-guided FNAB is the preferred initial diagnostic test for thyroid nodules and neck masses, recommended by multiple guidelines as accurate, economical, safe, and effective. 1, 2
Septations and cystic features do not exclude malignancy. Studies demonstrate that cystic thyroid nodules have a malignancy rate of approximately 17.6%, which is not negligible. 3
Ultrasound guidance specifically improves diagnostic yield in cystic lesions by facilitating directed biopsy of the solid component or cyst wall, addressing the historically high rate of nondiagnostic results from conventional palpation-guided aspiration of cystic lesions. 1, 3
Technical Approach for Optimal Results
Target the solid components and septations, not just the cystic fluid:
Direct the needle to sample the cyst wall and any solid portions within the septated areas under real-time ultrasound visualization. 1, 3
Ultrasound guidance increases specimen adequacy rates and reduces nondiagnostic samples from 30% (conventional technique) to approximately 9% in cystic lesions. 3
Request on-site cytopathology evaluation if available, as this further reduces inadequacy rates. 1
Critical Clinical Context
No clinical or imaging parameter reliably predicts benignity in cystic thyroid lesions:
Age, sex, lesion size, and echographic pattern do not significantly differ between benign and malignant cystic thyroid nodules. 3
The presence of septations alone does not stratify risk sufficiently to defer tissue diagnosis. 3
Management Algorithm After FNAB
If initial FNAB is inadequate or nondiagnostic:
Repeat ultrasound-guided FNAB with meticulous targeting of solid components before considering more invasive procedures. 1
Consider core needle biopsy if repeat FNAB remains nondiagnostic, as it has 95% adequacy and 94-96% accuracy for detecting neoplasia. 1
If FNAB shows benign cytology but clinical concern persists:
An adequate and negative FNA, while reassuring, should not preclude additional diagnostic procedures for patients with worrisome signs and symptoms, as false-negative results occur. 1
Maintain clinical and imaging surveillance, as false-negative rates exist even with adequate sampling. 1
Common Pitfalls to Avoid
Do not assume benignity based on cystic appearance alone – this is the most critical error, as guidelines explicitly warn against this assumption. 1
Do not perform palpation-guided aspiration – ultrasound guidance is mandatory for adequate sampling of cystic lesions. 1, 4
Do not accept inadequate samples without repeat biopsy – inadequate specimens require repeat sampling with optimized technique. 1
Ensure the procedure is performed by an operator trained in ultrasound-guided techniques with access to experienced thyroid cytopathology interpretation. 4