Follicular carcinoma arising in ectopic thyroid tissue: case report with fine-needle aspiration findings

Importance of ectopic thyroid tissue detected in the midline of the neck: single center experience

OBJECTIVE

Ectopic thyroid tissue (ETT) is a rare abnormality of the thyroid gland and the true prevalence and importance is not known. The aim of this study was to evaluate ultrasonography (US) guided fine needle aspiration biposy (FNAB) results, sonographic features, and frequency of ETT detected in the midline of the neck.

SUBJECTS AND METHODS

Five thousand five hundred and twenty outpatients who were referred to our thyroid clinic between September 2010 and April 2012 and underwent thyroid US, were retrospectively analyzed. Patients with ETT, detected in the midline of the neck in US were included in the study. Thyroid functions, sonographic features, and US guided FNAB results were evaluated.

RESULTS

There were 81 (81.8%) female and 18 (18.2%) male patients with a mean age of 50.9 ± 11.7. The ETT in the midline was present in 1.79% (99/5,520) of the patients. In the majority of the patients, benign sonographic features (isoechoic, regular margin, type 1 vascularization) were detected. There were 92 (92.9%) patients with a previous history of thyroidectomy and all were histopathologically benign. In 7 (7.1%) patients, there was no history of thyroid operation. FNAB results of ETT were benign.

CONCLUSION

This study evaluated the importance of ETT detected incidentally in the midline of the neck. Especially in patients with a history of thyroidectomy, the thyroid masses in the midline of the neck can be found as incidental with imaging methods. Our results suggests that the incidence of malignancy in this group is much lower than orthotopic thyroid nodules and they are often benign.

Lateral Ectopic Thyroid: A Case Diagnosed Preoperatively

Ectopic thyroid is an uncommon condition defined as the presence of thyroid tissue at a site other than the pretracheal area. When the process of embryologic migration is disturbed, aberrant thyroid tissue may appear. In most cases, ectopic thyroid is located along the embryologic descent path of migration as either a lingual thyroid or a thyroglossal duct cyst. In rare cases, aberrant migration can result in lateral ectopic thyroid tissue. Approximately 1 to 3% of all ectopic thyroids are located in the lateral neck. Ectopic tissue frequently represents the only presence of thyroid tissue; a second site of orthotopic or ectopic thyroid tissue is found in other cases. The presentation of ectopic thyroid as a lateral mass should be differentiated from metastatic thyroid cancer; other differential diagnoses include a submandibular tumor, branchial cleft cyst, carotid body tumor, and lymphadenopathy of various etiologies. In addition to the history and physical examination, the workup for a patient with a submandibular mass suspicious for ectopic thyroid should include (1) technetium-99m or iodine-131 scintigraphy, (2) ultrasonography and either computed tomography or magnetic resonance imaging, (3) fine-needle aspiration biopsy, and (4) thyroid function testing. No treatment is required for asymptomatic patients with normal thyroid function and cytology, but hypothyroid patients should be placed on thyroid hormone replacement therapy. Most cases are diagnosed postoperatively. Surgical treatment of ectopic thyroid should be considered when a malignancy is suspected or diagnosed, when the patient is symptomatic, or when thyroid suppression therapy fails.

Ectopic submandibular thyroid tissue with a coexisting normally located multinodular goitre: case report and review of the literature

The simultaneous finding of submandibular ectopic thyroid tissue and functional orthotopic thyroid gland is an extremely rare event. The present report describes the case of a woman presenting with a left submandibular mass, distant from a palpable multinodular goitre. Ultrasonography showed an ovoidal solid mass adjacent to the lower margin of the left submandibular gland. Cytological specimens showed colloid material and thyroid follicular cells with no malignant features. A preoperative CT scan demonstrated a very thin connection between the thyroid and the submandibular mass. The patient underwent total thyroidectomy and excision of the submandibular mass. The histopathological diagnosis of the thyroid tissue was multinodular goitre, and the submandibular mass was ectopic thyroid tissue showing a hyperplastic pattern. The main differential diagnosis of the submandibular mass was a metastasis from a well differentiated cancer. This case illustrates that an ectopic thyroid off the midline may not necessarily be a metastasis from a thyroid cancer.