Thyroglossal duct cyst, a congenital anomaly of the thyroglossalduct residual, is seen in 7% of the young adult population (1).Carcinoma development in thyroglossal duct cyst is quite rare andit is observed in less than 1% of patients (2,3). The most commonmalignant pathology is the papillary carcinoma of the thyroid(4). Diagnosis is usually made after pathological examination ofsurgically removed tissue. We planned to present a case who hadundergone surgery with the diagnosis of thyroglossal duct cystwhile its histopathology was reported as papillary carcinoma; yetafter our studies, we detect micropapillary cancer of the thyroid.
A forty-one year old male patient was admitted to the ear-nosethroatoutpatient clinic with the complaint of painless palpableswelling that he noticed three months ago. On physical examination;a 2x2cm palpable mass was found on neck midline between thyroidcartilage and hyoid bone. Patient had no history of radiation to theneck, and he was clinically euthyroid. The ultrasound performedon the neck by Radiology; a 20x15 mm irregular cystic mass lesioncontaining solid component was seen adjacent to the right lateralsuperior of the hyoid bone. The thyroid gland size was normal andits contour was smooth. The thyroid gland had homogeneous echopattern and no lesion was detected, which made difference in the eco of the gland. Patient was scheduled for the excision of the massand in the preoperative neck cranial computed tomography, in asimilar way, a 19x13 mm lobulated hypodense mass was seen inthe anterosuperior of the hyoid bone. There was neither pathologicallymph node in size and appearance nor space-occupying lesion inthe thyroid gland. The Tc-99m thyroid scintigraphy result was normal.Patient had Sistrunk operation in otolaryngology clinic. The result ofhistopathological examination was reported as papillary carcinomaarising from thyroglossal duct and with the aim of further examinationthe patient was directed to the endocrinology department. In thethyroid ultrasound performed in our clinic, a 2x3x3 mm hypoechoiclesion was detected in the right lobe close to the isthmus (Figure1). Lesions’ elastography score was measured as 4, and its strainindex was 2.67 (Figure 2). We did a fine-needle aspiration from thelesion and the result was reported as ‘papillary carcinoma’. Totalthyroidectomy and anterior neck dissection was performed. In thehistopathological evaluation; 2 papillary carcinoma lesions weredetected which were 4 mm and 2 mm in diameter. Among evaluated20 lymph nodes and thyroglossal remnant, no tumor was reported.
Te finding of mass in the neck is a common clinical finding and thusnumerous pathologies should be considered in differential diagnosis.Most of the masses are benign but malignant diseases should not beignored. Therefore, it is important to develop a systematic approachtowards a patient who has a mass in the neck. Benign tyroglossalchannel cysts are often detected as front neck masses which areasymptomatic, soft and has no tend to grow. Carcinoma developmentin thyroglossal duct cyst is quite rare and it is observed in less than1% of patients (2,3). Because of this rarity, we do not usually suspectof malignancy prior to surgical excision. However, as in our case, inthe presence of a mass that is fixed and rapidly increasing in size,physicians may suspect of malignancy. Older patients, female patients,and patients with the rapid growth of the lesion are more at risk interms of malignancy (5). In Carcinomas arising from the thyroglossalduct cyst, two histological origins have been described. First andmore frequent is thyroid elements and the second is carcinomasdeveloped from squamous cell epithelial. The most common cancerseen in thyroglossal cysts is papillary carcinoma, as in our case (85%).Because of the carcinoma development in thyroglossal duct cyst isvery rare, prior to surgery clinicians usually do not suspect of anoncologic diagnosis and as a result thyroglossal duct cyst carcinomadiagnosis is made by histopathological examination of samples aftersurgery. To overcome this difficulty, in patients who got diagnosedwith thyroglossal duct cysts, neck lymph nodes and thyroid glandneed to be examined in detail. In our case, the preoperative thyroidgland assessment was made by the radiology department, but 3 mmhypoechoic nodule could not be detected neither in ultrasound nor inscintigraphy. Elastosonography’s (ES) use for the diagnostic approachto thyroid nodules has become widespread in recent years. SI valuesdetermined by ESR, combined with the characteristics of the noduleusing ultrasound is a non-invasive, advantageous method in thedifferential diagnosis of thyroid nodules (8). In the literature, twomore case reports are available with both papillary carcinoma inthe thyroid gland and papillary carcinoma in thyroglossal duct cyst without pathologic lymph node in the neck (6,7). Therefore, in casesof thyroglossal duct cyst, even with a very little risk of malignancy, theprobability of papillary microcarcinoma in thyroid gland should beconsidered. We think that this is due to the thyroglossal duct thyroidmicrocarcinoma metastasis or multifocality of the papillary thyroidcarcinoma in two separate regions as a result of the same mutation.The detailed evaluation of thyroid gland and lymph nodes is crucial todetermine the type of operation that will be performed on the patient.
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