Laboratory Studies
To avoid complications, consider several studies in the preoperative evaluation of a thyroglossal duct cyst (TGDC). Confirmation of a normally functioning thyroid gland is important; therefore, always palpate the thyroid gland during the physical examination. If the gland is not palpated, ultrasonography or CT scanning may be valuable. If an ectopic thyroid gland is mistakenly diagnosed as a TGDC and removed, the patient requires lifelong thyroid replacement to prevent myxedema and complications of hypothyroidism.
Although not always the case, the patient with an ectopic thyroid often is hypothyroid and consequently has elevated thyroid-stimulating hormone (TSH). If hypothyroidism is suggested by the history, then a TSH test may be useful; however, an ectopic thyroid gland cannot be ruled out even in the presence of reference range TSH levels and a clinically euthyroid history. For this reason, ultrasonography, CT scanning, thyroid scanning, or MRI may be warranted to document a normal thyroid gland.
Imaging Studies
Preoperative imaging studies, including high-resolution CT scanning, contrast fistulography, and barium swallow esophagraphy, may be helpful in selective cases. These studies may be useful in defining the exact location, size, and course of the branchial cleft anomaly.
CT scanning is helpful in most situations. In the presence of an external sinus or fistula in the neck, fistulography may provide additional information on the course of the tract. In a patient with a history of recurrent lateral neck abscess, in which a branchial cleft anomaly with a possible internal sinus opening is suspected, a barium swallow esophagraphy may provide helpful information.
A study by Oyewumi et al indicated that ultrasonography can be used to differentiate thyroglossal duct cysts from midline dermoid cysts in children. According to the investigators, the study, which involved 91 patients, found three ultrasonographic variables — internal septae, an irregular wall, and solid components — that independently predict the presence of a thyroglossal duct cyst over a dermoid cyst. [8]
Other Tests
A thorough history and physical examination is usually all that is necessary to diagnose anomalies of the branchial cleft and thyroglossal duct. The history of a patient with a branchial cleft anomaly usually reveals a neck mass that may have fluctuated in size and level of pain and discomfort.
In adults with a cystic mass in the neck, obtain a careful history of squamous cell cancer risk factors. A complete physical examination of the head and neck must be performed on all patients. Perform a direct laryngoscopy in all patients who might have a metastatic cervical neck cyst secondary to an unknown primary squamous cell carcinoma. Direct laryngoscopy with hypopharyngoscopy and barium swallow esophagraphy often are useful in the treatment of a patient with a history of recurrent lateral neck abscess in whom a branchial cleft anomaly with a possible internal sinus opening is suspected. If an internal opening is observed on laryngoscopy, intubate the tract with a probe or a balloon embolectomy catheter. This facilitates identification and dissection of the sinus tract or fistula at the time of surgery.
Movement of the mass with deglutition and tongue protrusion is suggestive but not 100% sensitive or specific for a thyroglossal duct cyst (TGDC).
Diagnostic Procedures
If the mass is infected, a fine-needle aspiration can be performed to obtain a culture to direct antibiotic therapy; however, if too much fluid is aspirated, future dissection may be more difficult.
A study by Begbie et al indicated that frozen-section examination is more sensitive than fine-needle aspiration cytology (100% vs 75%, respectively) in detecting branchial cleft cysts. [9]
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Axial CT scan of a patient with a relatively small thyroglossal duct cyst.
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Axial CT scan of a first branchial cleft cyst.
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Axial CT scan of a second branchial cleft cyst.
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Axial CT scan of a third branchial cleft cyst.
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Preoperative photograph of a 20-year-old female who underwent a simple excision of a thyroglossal duct cyst 12 years ago in Europe. The patient has had multiple infections over the past 10 years. The patient was actively infected at the time of this photograph, as seen by the skin erythema and swelling.
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CT scan showing an infected recurrent thyroglossal cyst 12 years after simple excision.
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Surgical specimen from the patient in Image 5 with prior simple excision of a thyroglossal duct cyst. Fistula tract with surrounding skin, cyst, midportion of the hyoid bone (which was not removed on prior surgery), and cuff of the base of the tongue muscle were excised.
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Preoperative photograph of a man with a recurrent infected thyroglossal duct cyst.
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Axial CT scan of the man in Image 8 with an infected thyroglossal duct cyst.
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Intraoperative picture of the patient in Image 8 undergoing a Sistrunk procedure. The central portion of the hyoid bone is being resected along with the cyst, overlying skin, and cuff of the base of the tongue muscle.
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Postoperative picture of the patient in Image 8 after a successful Sistrunk procedure.
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CT scan of a man with a large neck lymphangioma.
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Intraoperative picture of the resection of a large cystic lymphangioma.
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Resection specimen of a well-circumscribed lymphangioma that was able to be removed in its entirety without sacrificing any surrounding structures.
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Second branchial cleft fistula.
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First branchial cleft cyst.
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Thyroglossal duct cyst.
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Picture of a 5-year-old-boy one year after having a Sistrunk procedure to remove a thyroglossal duct cyst.
