High-resolution ultrasound of thyroglossal cysts with special emphasis on the detection of cystic portions above the hyoid within the tongue base.

Background: Thyroglossal duct cysts (TGDCs) within the tongue base represent a challenge for the surgeon and are often the cause of recurrence.

Purpose: This study aimed to evaluate diagnostic performance of high-resolution ultrasound in TGDCs within the tongue base, compared to intraoperative findings. Furthermore, accuracy with which the detection of thyroid tissue in parts of the thyroglossal duct cyst was possible was investigated.

Methods: A total of 50 patients with TGDCs were examined by high-resolution ultrasound. Every thyroglossal cystic lesion was examined for the presence of solid thyroid tissue with colour-coded duplex sonography and evaluated according to American Thyroid Association (ATA) guidelines. Ultimately, 45 of the 50 patients underwent surgery (Sistrunk procedure).

Results: In 38/50 patients (76%), TGDCs were seen in their typical distal location inferior to the hyoid. Four patients (8%) had the thyroglossal duct cyst superior and inferior to the hyoid. The TGDC remnants only in the tongue base were recognised in 16% of cases (8 patients). Histological specimens revealed thyroid tissue within the TGDCs in 23 of the 45 patients (49%). Thyroid tissue was diagnosed preoperatively in 15 patients (65%) X ²(1, N = 23) = 2.13, p = 0.144. One patient exhibited suspicious features for thyroid cancer, which was confirmed histologically as papillary thyroid carcinoma.

Conclusion: High-resolution ultrasound represents quick, safe and reliable imaging for TGDCs on both sides of the hyoid bone (inferior and superior) with an impact on surgical planning. Furthermore, thyroid tissue within TGDCs can be revealed preoperatively and assessed for suspicious features.