Rare presentation of thyroglossal duct cyst after radiation therapy to the neck

Uncommon Insidious Dumbbell-shaped Double Thyroglossal Duct Cyst

As one of the most common congenital neck masses, thyroglossal duct cyst (TGDC) developed from the residual ductal epithelial cells in any remnants of thyroglossal duct. However, the reports of double TGDCs were rare. A 60-year-old male was referred to our department because of the presentation of an anterior neck mass. Only a hypodense oval mass inferior to hyoid bone was shown by computed tomography. During the Sistrunk operation, the dumbbell-shaped double TGDCs with the hyoid bone as the pivot were excised. No recurrence was observed. Before surgery, ultrasonography and computed tomography or magnetic resonance imaging should be conducted to verify the locations and sizes of TGDCs. During Sistrunk procedure, the rims of hyoid bone should be checked to avoid possible duct remnants.

Manifestations of radiation toxicity in the head, neck, and spine: An image-based review

BACKGROUND AND PURPOSE

Radiation therapy is an important component of treatment in patients with malignancies of the head, neck, and spine. However, radiation to these regions has well-known potential side effects, many of which can be encountered on imaging. In this manuscript, we review selected radiographic manifestations of therapeutic radiation to the head, neck, and spine that may be encountered in the practice of radiology.

METHODS

We conducted an extensive literature review of known complications of radiation therapy in the head, neck, and spine. We excluded intracranial and pulmonary radiation effects from our search. We selected complications that had salient, recognizable imaging findings. We searched our imaging database for illustrative examples of these complications.

RESULTS

Based on our initial literature search and imaging database review, we selected cases of radiation-induced tumors, radiation tissue necrosis (osteoradionecrosis and soft tissue necrosis), carotid stenosis and blowout secondary to radiation, enlarging thyroglossal duct cysts, radiation myelopathy, and radiation-induced vertebral compression fractures.

CONCLUSIONS

We describe the clinical and imaging features of selected sequelae of radiation therapy to the head, neck, and spine, with a focus on those with characteristic imaging findings that can be instrumental in helping to make the diagnosis. Knowledge of these entities and their imaging findings is crucial for accurate diagnosis. Not only do radiologists play a key role in early detection of these entities, but many of these entities can be misinterpreted if one is not familiar with them.

Prevalence and Features of Thyroglossal Duct Cyst on Ultrasonography, According to Radioactive Iodine Therapy: A Single-Center Study

Objective: The relationship between radioactive iodine therapy (RIT) and prevalence of thyroglossal duct cysts (TGDC) on ultrasonography (US) has not been reported. We assessed the prevalence and US features of TGDC according to RIT. Methods: From July 2017 to June 2018, 3,146 subjects underwent thyroid or neck US at our center. The presence or absence of TGDCs was prospectively investigated based on real-time US examination. Among the 3,146 subjects, 261 subjects were excluded because of <18 years of age, unclear information of RIT, or the presence of a radiation therapy history to the neck. Eventually, 2,885 subjects were included in this study. Results: Of the 2,885 subjects finally included, 126 (4.4%) showed a TGDC on US. Those with RIT history showed a higher prevalence of TGDCs than those without (no statistical difference, p = 0.062). In 697 male subjects, there were statistical differences in type of surgery, RIT history, and session number of RIT between those with or without TGDCs (p < 0.0001). In 126 subjects with TGDCs, only sex showed a significant difference between those with or without RIT history (p = 0.015). However, there were no significant differences in the location, size, and shape of TGDCs (p > 0.05). The common US features of TGDC were suprahyoid location, ~1 centimeter, and flat-to-ovoid or round shape. Conclusions: RIT may increase the prevalence of TGDCs, particularly in men.

Comparison of Prevalence and Ultrasonography Features of Thyroglossal Duct Cyst in Adults According to Radioactive Iodine Ablation

BACKGROUND This study aimed to evaluate the prevalence of thyroglossal duct cysts (TGDCs) on ultrasonography (US) and US features of TGDCs in adults, and to assess whether the prevalence or size of TGDCs increases after radioactive iodine ablation (RIA). MATERIAL AND METHODS Between July and December 2018, 2820 patients underwent thyroid or neck US examination, performed by 2 radiologists, at our center. On the basis of real-time US, the presence or absence of TGDCs was prospectively investigated by 2 radiologists. Among the 2820 patients, 54 patients who were <19 years of age or had a radiation therapy history to the neck were excluded. Eventually, 2766 patients were included. RESULTS Of the 2766 patients, 160 (5.8%) showed a TGDC on US. The mean size of TGDCs in RIA history (+) (n=36) and RIA history (-) (n=124) groups was 0.92±0.41 cm and 0.86±0.45 cm, respectively. There was no significant difference in size of TGDCs between RIA history (+) and RIA history (-) groups (p=0.684). Between the TGDC (+) and TGDC (-) groups, there was no significant difference in patient age, gender, reason for thyroid/neck US, type of thyroid surgery, and session number and application/no application of RIA (p>0.05). The prevalence rate of TGDCs in radiologist A and B was 4.9% (70/1427) and 6.7% (90/1339), respectively. TGDCs were more common in the suprahyoid neck, and the common shapes of TGDCs were flat-to-ovoid and round. CONCLUSIONS RIA may not be associated with the prevalence or enlargement of TGDCs.

Thyroglossal duct cysts: anatomy, embryology and treatment

Thyroglossal duct cysts are the most frequently encountered congenital abnormality of the neck, and are described extensively in the literature. The high incidence of this abnormality and its presence in all age groups requires clinicians to be aware of the clinical features, etiology, and current treatment options. Because it is readily accessible, relatively inexpensive, and non-invasive, sonography is arguably the ideal initial investigation. Computerized tomography and fine needle aspiration biopsy are often utilized as supplementary techniques for confirmation of the diagnosis. The treatment of choice for thyroglossal duct cysts continues to be the classic Sistrunk procedure, developed in 1920, although several modifications have since been employed. In this review, we aim to explore the embryological development, clinical presentation and diagnostic features of thyroglossal duct cysts. In addition, a useful adaptation to the Sistrunk procedure and the recent application of OK-432 therapy as a promising alternative for treatment of thyroglossal duct cysts will also be discussed.

Enlargement and transformation of thyroglossal duct cysts in response to radiotherapy: imaging findings

BACKGROUND AND PURPOSE

Thyroglossal duct cyst remnants (TGDC) are a common midline neck mass that is mostly encountered in childhood. Enlargement after an upper respiratory tract infection or, rarely, cancer within TGDC, is a well-documented phenomenon. In the pediatric population, it rarely presents a diagnostic quandary. However, in an adult population, especially one treated for head and neck cancer with radiation therapy (RT), any enlarging cystic mass would be concerning and would raise the specter of metastatic disease. We propose that inflammation associated with RT results in secretory stimulation and/or obstruction of a persistent thyroglossal duct, resulting in changes within a pre-existing TGDC.

MATERIALS AND METHODS

We present a case series of 8 patients with subclinical TGDC treated with RT for various head and neck cancers, in which we radiographically observed enlargement or cystic transformation (more cystlike appearance) of the cyst.

RESULTS

In all patients there was in retrospect a small thyroglossal remnant, though not necessarily a discernible cyst, that was observed after radiotherapy to enlarge and become more cyst-like.

CONCLUSIONS

In patients with pre-existing TGDC undergoing RT to the neck, enlargement and cystic transformation may be encountered radiographically and should not be misinterpreted as a tumor. Our series bolsters a recently reported description of the same phenomenon.