Visual Vignette Hassan Shawa, MD; Rena Vassilopoulou-Sellin, MD; Steven G. Waguespack, MD From the Department of Endocrine Neoplasia and Hormonal Disorders, The University of Texas MD Anderson Cancer Center, Houston, Texas Case presentation: A 67-year-old man with multiple myeloma was referred for abnormal hormone levels, which were ultimately attributed to hypopituitarism due to a nonfunctioning pituitary macroadenoma. On the initial physical examination, a 4-cm midline neck mass that moved cranially with swallowing and tongue protrusion was identified (Fig. 1). The patient denied dysphagia, dysphonia, dyspnea, stridor, or neck tenderness and recalled that the mass had been present since childhood. Post-contrast axial views from a computed tomography scan of the neck revealed a cystic lesion anterior to the thyroid cartilage (Fig. 2a) and extending between the thyroid cartilage notch and the hyoid bone (Fig. 2b) into the preepiglottic space posterior to the hyoid bone (Fig. 2c). In retrospect, the lesion could be identified on a magnetic resonance imaging (MRI) scan of the cervical spine obtained 7 years prior and had similar dimensions and extension. There was no change in size or development of symptoms related to the mass after 3 years of follow-up. What is the diagnosis?

Fig. 1

Fig. 2a,b,c

Answer: Thyroglossal duct cyst (TGDC). TGDC represents a cystic expansion of a remnant of the thyroglossal duct tract and is the most common etiology for a midline neck mass, with 50% diagnosed in adulthood (1). TGDC may occur anywhere along the thyroglossal duct tract from the foramen cecum at the base of the tongue to the level of the suprasternal notch. Classically, it is located in close proximity to the hyoid bone (1). Intralaryngeal extension of a TGDC, as seen in our patient, is a rare finding (2). The vertical movement of a TGDC with swallowing or tongue protrusion occurs because of its embryologic relationship with both the hyoid bone and the foramen cecum. This is a reliable diagnostic sign that can distinguish TGDC from a dermoid cyst, the second most common cause of a midline neck mass (3). The differential diagnosis also includes ranula, midline cervical cleft cyst, isthmus thyroid nodule, hypertrophic pyramidal lobe, laryngocele, and midline lymphadenopathy (3). The most common clinical presentation of TGDC is a painless mass or an infection, which occurs in one-half of cases either as a single or recurrent event, although 3 to 4% may remain undetected (1,3). In addition, an incidental primary thyroid carcinoma has been detected in 1 to 2% of TGDC cases (1,3). Surgery (Sistrunk procedure) is typically recommended in order to prevent infection. However, the natural history of TGDC in our patient would suggest that complications may not occur in all TGDC cases, even those with intralaryngeal extension. DISCLOSURE

The authors have no multiplicity of interest to disclose.

REFERENCES 1. Ren W, Zhi K, Zhao L, Gao L. Presentations and management of thyroglossal duct cyst in children versus adults: a review of 106 cases. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2011;111:e1-e6. 2. Bando H, Uchida M, Matsumoto S, Ushijima C, Dejima K. Endolaryngeal extension of thyroglossal duct cyst. Auris Nasus Larynx. 2012;39:220-223. 3. Foley DS, Fallat ME. Thyroglossal duct and other congenital midline cervical anomalies. Semin Pediatr Surg. 2006;15:70-75. Address correspondence to Dr. Steven G. Waguespack, Department of Endocrine Neoplasia and Hormonal Disorders, The University of Texas MD Anderson Cancer Center, 1400 Pressler Street, Unit 1461, Houston, TX 77030. Email: [email protected]. Published as a Rapid Electronic Article in Press at http://www.endocrinepractice.org on November 18, 2013. DOI:10.4158/EP13382.VV Copyright © 2014 AACE

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