Abstract
Primary papillary thyroid carcinoma arising in a thyroglossal duct cyst (TGDC) is a rare but well-documented phenomenon. Typically, patients present with a painless, midline neck mass found to be a TGDC on routine imaging (computed tomography or ultrasound), and undergo a Sistrunk procedure for removal. Papillary thyroid carcinoma is then found incidentally within the cyst on histopathologic examination. We describe a unique case of papillary thyroid carcinoma as a lateral neck lesion without clinical, radiographic or histologic evidence of a TGDC or primary neoplasm in the thyroid
Highlights
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Papillary thyroid carcinoma can develop in cases without primary neoplasm in the thyroid gland itself.
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Fine needle aspiration should be performed to establish definitive diagnosis of an unknown neck mass.
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Typically a papillary thyroid carcinoma of thyroglossal duct cyst is slow growing, painless, and midline.
Primary papillary thyroid carcinoma arising in a thyroglossal duct cyst (TGDC) is a rare but well-documented phenomenon. Typically, patients present with a painless, midline neck mass found to be a TGDC on routine imaging (computed tomography or ultrasound), and undergo a Sistrunk procedure for removal. Papillary thyroid carcinoma is then found incidentally within the cyst on histopathologic examination. We describe a unique case of papillary thyroid carcinoma as a lateral neck lesion without clinical, radiographic or histologic evidence of a TGDC or primary neoplasm in the thyroid.
1
Introduction
Rare cases of primary papillary thyroid carcinoma in thyroglossal duct cyst remnants are well-documented in the literature. Thyroglossal duct cysts (TGDCs) arise due to failure of obliteration of the thyroglossal duct during embryonic development [ ]. Typically, primary carcinomas of TGDCs are found incidentally after excision of a TGDC via a Sistrunk procedure, and there is an incidence of less than 1% [ ]. More than 90% of all TGDC cancers are papillary type thyroid carcinomas [ ]. Patients reported in current literature typically present with a slow-growing, painless, midline neck mass with some endorsing symptoms of mass effect (i.e. dysphagia or dyspnea) [ , , , ]. A vast majority of reported patients show evidence of TGDC on imaging (either computed tomography or ultrasound) without pre-operative evidence of neoplasia. A minority of reported patients undergo fine needle aspiration pre-operatively due to radiographic suspicion of neoplasm, typically the size of the cyst or calcifications within the lesion [ , ]. Our purpose is to summarize an unusual case of papillary thyroid carcinoma presenting as a lateral neck extension seen at Parkland Memorial Hospital.
1.1
Case presentation
A 27-year-old male with no significant past medical history presented to Parkland Memorial Hospital’s urgent care clinic with the complaint of a neck swelling that began approximately 4 months prior. He reported that the swelling had progressively increased in size and the area had been mildly tender. The patient denied any fevers, chills, nausea, vomiting, shortness of breath, issues tolerating secretions, or unintentional weight loss. His family history was noncontributory. He endorsed social use of alcohol, and denied any tobacco or illicit drug use. On examination, the patient was well-developed and in no acute distress, with stable vital signs. He had no significant intraoral findings with normal dentition and normal saliva production from all glands. Cervical examination revealed a 3-cm firm neck mass that protruded from his right submandibular (level 1b) area. The mass was fixed, not pulsatile, non-indurated, non-fluctuant, and there was no evidence of lymphadenopathy. Prior to his urgent care visit, the patient had an ultrasound of the lesion at an outside facility that revealed a heterogenous solid and cystic lesion of uncertain etiology that measured 2.9 x 4.5 × 4.2 cm in the right submandibular area. He was discharged home with ibuprofen and a follow-up appointment with a primary care provider (PCP) after a nonreactive HIV screening, with instructions to have a CT scan with or without fine needle aspiration biopsy. At his PCP follow-up visit, a CT scan and ultrasound of lesion were ordered. Due to increasing pain and discomfort associated with the lesion, the patient returned to the Parkland emergency department approximately one week later, prior to his imaging appointment. During this encounter, oral and maxillofacial surgery (OMS) was consulted, and a CT soft tissue scan of the neck with IV contrast was ordered. The CT scan revealed a “heterogenous mass centered at the right sublingual space with trans-spatial involvement, containing calcific foci, probable fluid levels, mild associated mass affect, and patchy enhancement. The main diagnostic consideration is a venolymphatic malformation” ( Figure 1 ). Nonemergent magnetic resonance image (MRI) of the face could be helpful as clinically warranted.” He underwent a follow-up ultrasound and MRI of the lesion, both of which showed findings consistent with a venolymphatic malformation ( Figure 2 ). An ultrasound-guided fine needle aspiration was also ordered by the OMS team. Interventional radiology canceled this procedure due to prior imaging showing pathognomonic characteristics of a venolymphatic lesion, and recommended sclerotherapy.
