Atypical thyroglossal duct anomalies

Prevalence of thyroid gland tissue in midline neck dermoid cysts in children and a proposed new 'thyroglossal entrainment' hypothesis for their formation

BACKGROUND

Thyroglossal duct cysts and dermoid cysts both commonly present as midline neck lumps in children. They are treated as separate entities with different embryological origins. There are isolated reports of thyroid gland tissue in a dermoid cyst, concurrent thyroglossal and dermoid cysts, and cysts with mixed histology. It is not known if these are rare or common.

METHODS

All children undergoing excision of a congenital midline neck cyst between January 2017 and December 2022 were identified. Histopathology slides were reviewed in detail.

RESULTS

In 53 children, there were 26 thyroglossal duct cysts, 24 dermoids, 1 lymph node and 2 with no diagnostic material identified. Five dermoids (28 per cent) had associated thyroid gland tissue, and 1 (4 per cent) had hybrid histology with keratinising and respiratory epithelium. Infection occurred in 17 per cent of dermoids prior to excision and 8 per cent of dermoids recurred after excision.

CONCLUSION

Hybrid histology, infection and recurrence are all common in midline neck dermoids. A new theory for their embryological origin is proposed, with the suggestion that some may need more extensive surgery.

The Outcome of Treatment for Thyroglossal Tract Anomalies

Background Thyroglossal tract anomalies are the most common cause of midline neck swelling. Thyroglossal cysts present between the base of the tongue and cricoid cartilage as painless, midline swelling that moves on deglutition and protrusion of the tongue. If the thyroglossal cyst gets infected or is violated surgically, it can result in a thyroglossal sinus or fistula. Investigations in patients with suspected thyroglossal cysts include a thyroid function test, ultrasonography of the neck, and fine needle aspiration cytology (FNAC). Computed tomography (CT) or magnetic resonance imaging (MRI) can be done for larger cysts or suspected malignancies. The gold standard treatment is Sistrunk surgery. Recurrence rates with Sistrunk surgery are lower when the surgery is performed accurately. This study was conducted to document the clinical presentation and treatment outcome in patients treated for thyroglossal tract anomalies. Methods This is a retrospective analysis of 46 medical case records of patients operated on for thyroglossal tract anomalies at a rural tertiary care hospital from April 1995 to April 2021. Patients fulfilling the inclusion and exclusion criteria were evaluated with a detailed history, various clinical presentations, location, extent of anomalies, and thyroid function test results documented. Ultrasound images were reviewed, and the findings were documented. All patients have consent, and they underwent Sistrunk surgery. Patients in whom the normal thyroid gland was found to be absent were started on replacement thyroxine after surgery. The specimen was subjected to histopathological examination by a senior pathologist. The outcome regarding complications, recurrence, and further treatment were reviewed. The outcome of the thyroglossal fistula was compared with that of thyroglossal cysts, and the outcome of infrahyoid thyroglossal tract anomalies was compared with that of suprahyoid thyroglossal tract anomalies. Results In this study, among the 46 patients, 24 (52.2%) were female and 22 (47.8%) were male. The minimum age was three years, the maximum was 58, and the mean was 20.6 years. In this study, 71.7% of the patients were diagnosed with thyroglossal cysts, 10.9% had thyroglossal fistulas, and two had lingual thyroids. The most common location of the cyst was infrahyoid (73.9%). 44 patients underwent Sistrunk surgery, and two patients diagnosed with lingual thyroid underwent excision. Three patients had complications (two pharyngo-cutaneous fistulas, one wound dehiscence), and all were managed conservatively. There were no recurrences in our study. Conclusion Thyroglossal tract anomalies are the most common congenital cervical anomalies. A complete Sistrunk procedure includes the removal of the entire thyroglossal tract, inclusive of the body of the hyoid bone along with the cuff of base tongue tissue, and gives the best result for thyroglossal tract anomalies.

Thyroglossal duct cyst and sinuses: a 20-year Los Angeles experience and lessons learned

BACKGROUND

First described in 1920 and later modified in 1928, the Sistrunk procedure substantially reduced the incidence of recurrence of midline neck cysts compared with a local excision or cystectomy. The purpose of this study was to determine if the rate of recurrence was influenced by performing either a 'classic' or a 'modified' Sistrunk procedure, if the recurrence rate was influenced by the physician's training, how successful we have been in managing patients with a recurrence? Finally, is outpatient surgery safe for Sistrunk procedures?

METHODS

We performed a retrospective review of all patients with a thyroglossal duct remnant (TGDR) who were seen at the Children's Hospital Los Angeles (CHLA) from 1990 to 2010. The following data were collected: patient age, gender, presence or absence of a pre-operative infection, imaging studies, type of procedure performed, the attending surgeon's training background, inpatient or outpatient status, and complications.

RESULTS

A total of 128 patients (61% male, 39% female) met the inclusion criteria. The age ranged from 2 months to 14 years (mean of 5.1 years). A total of 137 procedures were performed; 114 (83.2%) for primary and 23 (16.8%) for secondary disease. Complications included post-operative infection (10.9%), recurrence of disease (6.6%), undesirable scar (5.8%), and fistula (2.9%). Surgeons with fellowship-training in pediatric otolaryngology had a recurrence rate of 4.0% and surgeons with fellowship-training in pediatric surgery or pediatric plastic surgery had a recurrence rate of 30.1%. Twenty patients had a 'classic' Sistrunk (14.6%) and 117 (85%) had a 'modified' procedure. Patients were admitted after surgery in 78 cases (56.9%) and 59 patients (43.1%) had an outpatient (OPD) procedure.

CONCLUSIONS

There is no place for cystectomy in the treatment of TGDR. A 'modified' Sistrunk procedure is the procedure of choice in both primary and revision cases. Wide local excision of recurrences is required and a 'classic' Sistrunk should be considered. Specific training to gain an intimate knowledge of the anatomy in and around the larynx and experience with multiple cases reduces the incidence of recurrence. Outpatient surgery is safe and effective for selected patients who undergo a Sistrunk procedure.

Lingual thyroglossal duct cysts--a review

OBJECTIVES

Lingual thyroglossal duct cysts (TGDC) are rare and liable to be missed in a cursory clinical examination. This study aimed to report the details of lingual TGDC from the authors' series and review existing literature on the entity.

METHODS

A 12 year retrospective survey of all cases of thyroglossal duct anomalies managed at a tertiary teaching hospital was conducted to identify those with lingual TGDC. Their clinical presentation, investigations, diagnosis and management were analysed. Case series from anecdotal published English literature were critically reviewed with particular regard to diagnosis and management.

RESULTS

Of 78 cases of thyroglossal duct anomalies, 3 were lingual TGDC. All were females. One neonate presented with feeding difficulty and was clinically misdiagnosed as a ranula. The two older children presented with a cyst at the foramen caecum. The varied imaging and diagnostic dilemma are presented. The older children had cysts abutting the hyoid and were managed with transoral excision and a Sistrunk procedure; the neonate was managed with transoral excision only. This report also reviews the sparse literature and discusses specific issues in their treatment. The differential diagnoses encompass a wide array of developmental and neoplastic entities. Specific anatomic imaging with USG/CT/MRI and functional evaluation with radionuclide thyroid scan are essential investigative modalities. Besides a classical Sistrunk procedure and simple transoral excision, newer less invasive treatment options including marsupialisation and alcohol ablation have been reported.

CONCLUSIONS

In conclusion, the diagnosis and management of lingual TGDC needs to be individualised depending on their presentation and anatomic location. The Sistrunk's procedure is ideal for those in close proximity to the hyoid; however complete cyst excision would suffice in the rest.