Ectopic thyroid tissue is a rare developmental abnormality involving aberrant embryogenesis of the thyroid gland during its passage from the floor of the primitive foregut to its final pre-tracheal position. Its prevalence is about 1 per 100000-300000 people, increasing to 1 per 4000–8000 patients with thyroid disease [1,2]. Ectopic thyroid is most common in females, especially in populations of Asian origin [3,4]. It may occur at any age, from 5 months to 40 years, but it is most common at younger ages. We report the course and management of a child with ectopic thyroid which mimicked as thyroglossal duct cyst.

An 8-year-old female child presented to our out-patient department with history of midline neck mass first noted at one year of age. Since its early presentation, this midline mass had increased in size, more so in recent past. There was no history of dysphagia, dyspnea, recurrent respiratory tract infections and there was no history suggestive of hypothyroidism or thyrotoxicosis. Patient was evaluated earlier and provisionally diagnosed to have throglossal duct cyst and planned for surgery. Preoperative investigation revealed hypo-thyroidism, so she was referred to our department for the management of hypothyroidism prior to excision.

On examination, the general health condition of child was normal with height of 121cm,weight of 22 kg, patient had pre-pubertal sexual maturity. A midline firm neck swelling 2×2 cm in size in the hyoid region moving with deglutition and protrusion of tongue was noted (Fig. 1). Systemic examination including cardiovascular and gastrointestinal systems were normal.

Fig.1 Showing midline neck swelling.

The most common site of ectopic thyroid is a lingual thyroid. The wall of a thyroglossal duct cyst is the second most common site for ectopic thyroid tissue. Up to 1 to 2 percent of patients presenting with what appears to be a thyroglossal duct cust TGDC have an ectopic thyroid gland [5,6]. Ectopic thyroid is mostly asymptomatic, but approximately a third of patients present with hypothyroidism, hyperthyroidism is exceptionally rare. These conditions cause enlargement of the gland thereby obstructive symptoms. With treatment size decreases, but surgical excision may become necessary in some cases.

Although most of the available literature state the incidence of ectopic thyroid tissue in presumed thyroglossal duct cyst is 1-2% [7]. Gupta, et al. [8] reported in their series that when screened by pre-operative ultra sound, this incidence is substantially less. Neverthless to prevent inadvertent removal of only functioning thyroid tissue and subsequent complications, they proposed routine preoperative USG in suspicious thyroglossal duct cyst.

Contributors: All authors contributed to the management of case and drafting the paper.

Funding: None; Competing interests: None stated.

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