Originally, TGDCs were removed through simple cyst exeresis, but presented recurrence rates as high as 50%. In 1893, Schlange [10] proposed the excision of the central portion of the hyoid bone together with the cyst and the whole duct, that reduced the rate of recurrence to nearly 20%. Eventually, in 1920 Sistrunk [11] described what became the standard surgical management of this congenital abnormality: an en bloc exeresis of the cyst, central hyoidectomy, and tract excision, extended through the tongue base tissue 2–3 mm up to the foramen cecum, including mucosa. The recurrence rate after the original Sistrunk procedure was around 1–5%; therefore in 1928, Sistrunk [12] himself modified his original technique to include the lingual muscle up to (but not including) the tongue mucosa. The modified Sistrunk procedure remains the gold standard treatment for symptomatic TGDC [18].

Incidence of re-operation after thyroglossal tract surgery has been impressively reduced since Schlange and Sistrunk [15]. However, even after a properly performed cyst exeresis through modified Sistrunk procedure, recurrence rates of TGDC reported in literature are still 7.6% (0–28%). [19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34]

It seems to be no correlation between patient’s sex or positioning of drainage, and recurrence of the disease.

Amongst recognized risk factors for clinical recurrence, instead there are: presence of extensive inflammation at time of surgery, multiple number of cysts and/or TGDs, severe inflammation at time of surgery or presence of TGDC fistula.

Firstly, inflammation at the time of surgery markedly increased the risk of recurrence. It is likely that repeated episodes of inflammation may promote scarring and obscure tissue planes, making eventually surgical excision more difficult and increasing the risk of recurrence.

This evidence may suggest the possible detrimental impact of a history of infection. In any case, the role of recurrent infections appears to be controversial, and evidence of its effects is not clear: while some reports documented a significant increased risk of recurrence after multiple infections [20, 30], others reported a slight increased risk [22, 40] and only one failed to observe any association [23]. In addition, multicystic presentation of the lesion may play a role and can be associated with a markedly increased risk of recurrence, speculating that incomplete removal of the cyst at surgery may occur especially when lesions are multicystic while children with multicystic lesions may be at increased risk of aberrant locations that are not detected at the time of first surgery [13]. Finally, risk factors analysis identified a possible role of younger age and post-surgical infections yet data are scanty or inconsistent [13].

The most important predicting factor of recurrence is the extent of surgical en-bloc resection: when simple excision is performed and hyoid bone remains intact, recurrences occur in 55.6% of the patients [35, 36]. As mentioned previously, recurrence rate of TGDC after Sistrunk procedure is around 16.4% (4.4–40.8%). Some authors suggested even the “extended Sistrunk procedure” [33]: this technique consists in the dissection en-bloc until the sternocleidomastoid muscle margin is encountered and proceeds until the pretracheal fascia and a 10-mm cuff of tongue base is removed in continuity with the specimen. However, due to the wider excision of underlying tissues, this procedure carries a higher risk of complications and damage to surrounding structures like recurrent laryngeal nerve, jugular vein and artery and the trachea [37]. Therefore, in order to perform a satisfactory and sufficient resection, the correct preoperative diagnosis of TGDC is crucial to be performed. Differential diagnosis include: cystic metastatic lymph node, dermoid cyst, second branchial cleft cyst or isthmic thyroid cyst [38]. US is the gold standard imaging to study TGDCs and it may help in the differential diagnosis with other neck masses; the presence of hyperechoic structures is typical of epidermoid cyst, even if TGDCs have not a decisive pattern. They may be heterogeneous (41.6%), anechoic (25%), homogenously hypoechoic (16.7%) or pseudosolid (16.7%) [39].

Eventually, histopathological analysis is an extremely useful tool in order to complete the diagnostic and therapeutic process. Indeed, the phenomenon of arborization has been reported by several studies [16, 40, 41], even though its role in recurrence is still controversial. The TGD can be located anteriorly to the hyoid bone, posteriorly to it or it can be enclosed within the bone itself. The anterior location appears to be the most common one, given the ventral pathway followed by the TGD during embryogenesis. TGD position is crucial, because the non-identification of a dominant duct during surgical removal may lead to persistence and recurrence. With respect to arborization, Chandra et al. suggested minor TGDs to be more susceptible to inflammation, leading to increased difficulty in surgical removal.

In our study, over 80% of patients presented arborization of the TGD at histopathological examination. In half of cases, the correct location of TGD with respect to the hyoid bone was not identified due to extensive inflammation. This finding confirms the aforementioned hypothesis of increased inflammation occurring along with arborization. The high proportion of arborization within the specimen might be related to the specific dissection carried out in between the cartilage portion of the hyoid, being its lateral parts not ossified when considering the pediatric population up to fifteen years of age [7]. On the other hand, only two patients presented recurrence of the disease: both of them presented arborization at histopathological analysis and had a history of recurrent inflammation.