Imaging identifies submandibular ectopic thyroid tissue

The identification of submandibular ectopic normal thyroid in the lateral neck with a coexisting normally located and functional thyroid gland is rare. Ectopic normal thyroid tissue in the midline location is most commonly related to aberrant migration along the thyroglossal duct (ie, lingual thyroid). A 54-year-old man with a 6-month history of visible asymptomatic swelling in the right submandibular region had ultrasonography and Tc-99m pertechnetate imaging.     

Double thyroid ectopia (with incidental papillary thyroid microcarcinoma) (2010: 8b)

We present the case of a 45-year-old man with a long-standing history of a slow-growing left submandibular mass. Imaging was diagnostic as it disclosed an absent orthotopic thyroid gland and heterogeneous masses, with both solid and cystic components, as well as calcifications in the left sublingual/submandibular space and in the left paramedian aspect of the tongue base, consistent with double thyroid ectopia, originating from central and lateral thyroid anlages, respectively. Pathology confirmed an ectopic thyroid goiter in the left submandibular space with an incidental papillary microcarcinoma. Scintigraphy also demonstrated ectopic thyroid tissue in the left tongue base.     

Scintigraphic visualization of glossal thyroid tissue during the follow-up of thyroid cancer patients

PURPOSE: Nests of thyroid tissue in the tongue are described in about 10% of necropsies. This ectopic thyroid tissue usually lies dormant, but may manifest itself during times of increased stimulation. The aim of our study was to assess the frequency of lingual thyroid visualization on I-131 diagnostic whole-body scan during the follow-up of thyroid cancer patients. MATERIAL AND METHODS: We reviewed the files of 548 consecutive patients who underwent a diagnostic whole-body scan with 200 MBq of I-131 between January 2000 and December 2005, as part of the follow-up for a differentiated thyroid cancer. Every patient had been previously treated with a total thyroidectomy and had received 3.7 GBq (100 mCi) of I-131 for remnant ablation. RESULTS: A focus of uptake located between the 2 submandibular salivary glands, suggestive of ectopic thyroid tissue in the tongue or in the upper part of the thyroglossal duct, was found in 5 of the 548 patients (0.9%). In only one of these patients was the uptake visible at the time of postsurgery thyroid remnant ablation scan. Thyroglobulin (Tg) levels were positive under stimulation in 3 of the 5 patients, and another patient had undetectable Tg, but positive anti-Tg antibodies. Radiologic imaging (MRI and/or ultrasound) was performed in 3 patients and confirmed the presence of a mass suggestive of ectopic thyroid tissue in two. Invasive lingual biopsy was not performed to verify the benign nature. CONCLUSION: When examining whole-body scans (therapeutic or diagnostic) in a patient with persistent Tg detection after thyroid ablation, one should carefully search for any uptake between the submandibular glands that may be suggestive of ectopic tissue.     

Lateral ectopic thyroid mimics carotid body tumor on Indium-111 pentetreotide scintigraphy

A 34-year old woman with past history of anxiety, depression, and hypothyroidism resulting from prior total thyroidectomy for multinodular goiter presented with complaints of palpitations, sweating, and tachycardia. Clinical examination revealed a painless right lateral neck mass. USG/CT of the neck revealed the soft tissue mass located at the right carotid bifurcation. A subsequent Indium-111 pentetreotide somatostatin receptor scintigraphy (SRS) demonstrated tracer uptake in the mass. Hence, secretory carotid body tumor/paraganglioma was strongly suspected. However, post-surgical histopathological specimen revealed only benign thyroid follicles indicative of lateral ectopic thyroid with no evidence of neuroendocrine cells or malignancy. This case highlights the importance of considering lateral ectopic thyroid, a very rare entity, in the differential diagnosis for carotid bifurcation masses. Also highlighted is the false positivity from normal but ectopic thyroid tissue on Indium-111 pentetreotide SRS mimicking a paraganglioma.     

Lateral ectopic thyroid mimics carotid body tumor on Indium-111 pentetreotide scintigraphy

A 34-year old woman with past history of anxiety, depression, and hypothyroidism resulting from prior total thyroidectomy for multinodular goiter presented with complaints of palpitations, sweating, and tachycardia. Clinical examination revealed a painless right lateral neck mass. USG/CT of the neck revealed the soft tissue mass located at the right carotid bifurcation. A subsequent Indium-111 pentetreotide somatostatin receptor scintigraphy (SRS) demonstrated tracer uptake in the mass. Hence, secretory carotid body tumor/paraganglioma was strongly suspected. However, post-surgical histopathological specimen revealed only benign thyroid follicles indicative of lateral ectopic thyroid with no evidence of neuroendocrine cells or malignancy. This case highlights the importance of considering lateral ectopic thyroid, a very rare entity, in the differential diagnosis for carotid bifurcation masses. Also highlighted is the false positivity from normal but ectopic thyroid tissue on Indium-111 pentetreotide SRS mimicking a paraganglioma.     

Papillary carcinoma in ectopic thyroid detected by TJ-201 scintigraphy

A 37-year-old man with papillary carcinoma in an ectopic thyroid is presented. Excisional biopsy revealed the cervical mass to be a metastasis from thyroid cancer. X-ray, ultrasonography, and computed tomography, however, failed to identify the primary tumor in the thyroid. Incidental TI-201 uptake was noted in the midline of the anterior neck, and a palpable nodule was discovered in this area. Fine needle aspiration cytology demonstrated Class V papillary adenocarcinoma, and subsequent surgery confirmed a papillary carcinoma in the ectopic thyroid. This case suggests the usefulness of TI-201 scintigraphy for the detection of ectopic thyroid malignancy.     

MR IMAGING OF THE LINGUAL THYROID: Comparison to other submucosal lesions

Purpose: To study MR findings for clues to the diagnosis of lingual thyroid.Material and Methods: MR findings and clinical and scintigraphic data of 5 cases of lingual thyroid were reviewed and the MR findings were compared to those of 16 cases of other submucosal lesions in the base of the tongue.Results: Four of the 5 patients with lingual thyroid were women and all had hypothyroidism. MR imaging depicted lingual thyroid in the midline in the base of the tongue (n=5) and additional ectopic thyroid glands in the floor of the mouth (n=2) or between the right and left sternohyoid muscles (n=1). Ectopic thyroid glands appeared isointense or hyperintense relative to muscle tissue on T1-weighted images and showed slight or fair contrast enhancement. All glands had low to intermediate T2 signal, which was also seen in 1 case of non-Hodgkin's lymphoma and 1 case of adenoid cystic carcinoma. All ectopic thyroid glands had well-defined margins, whereas malignant tumors tended to have ill-defined margins and to invade the surrounding structures. All but the 5 cases of lingual thyroid had an MR-demonstrable thyroid gland in the normal cervical position.Conclusion: A well-defined mass of low-intermediate T2 signal in the midline base of the tongue, neither with invasive tendency nor with a cervical thyroid gland in the normal site on MR imaging, may strongly indicate lingual thyroid.     

A unique case of thyroid dysgenesis in a neonate

Neonates with congenital hypothyroidism often demonstrate ectopic thyroid tissue. However, 2 sites of abnormally located thyroid tissue are exceptionally rare with only one other published case on a neonate. The authors present a unique case of a neonate who was found to have congenital hypothyroidism on laboratory screening; Tc-99m pertechnetate scintigraphy demonstrated 2 sites of abnormal uptake: one at the base of the tongue and the other in the midline at the expected location of the thyroid bed.     

Dual thyroid ectopy: case report and review of the literature

Dual ectopic thyroid glands rarely occur, and only six cases have been reported in the literature. The authors describe a 14-year-boy who had a midline neck swelling for 8 to 9 years. The swelling increased gradually, but he had no pressure symptoms. The thyroid hormone profile showed a moderately increased thyroid-stimulating hormone value and normal T3 and T4 levels. A Tc-99m sodium pertechnetate thyroid scan showed dual ectopic thyroid glands in the sublingual and subhyoid regions.     

Dual ectopic thyroid: case series and review of the literature

Ectopic thyroid tissue is an uncommon congenital aberration. It is further unusual for ectopic thyroid to be present at 2 different sites simultaneously. Only 19 cases of dual ectopic thyroid have been reported in the English literature. Most of the patients were adolescents and presented with anterior neck swelling with or without altered metabolic status. Lingual/sublingual thyroid was the most common ectopic location. Subhyoid was the most common site of a second ectopic thyroid in these patients. The thyroid scan has been used successfully to diagnose ectopic thyroid tissue. We report 4 such cases in which ectopic thyroid tissue was simultaneously present at 2 different locations using thyroid scanning. The literature of already reported cases is reviewed in detail.     

A comparison of the effective dose from scanography with periapical radiography

OBJECTIVES: To compare organ and effective doses from analogue scanographic and periapical radiography. METHODS: Thermoluminescent dosimeters (TLD-700) were inserted in the parotid glands (bilateral), submandibular glands (bilateral) and bone marrow (left ascending ramus) of three human cadavers. Dosimeters were also attached to the skin, thyroid gland and lens of both eyes. Central, left lateral and left posterior scanograms were obtained with a Cranex Tome (Soredex, Helsinki, Finland) multimodal imaging system. A similar procedure was applied for periapical radiographs of the midline, left lateral and left molar regions using E-speed film both with and without rectangular collimation. Organ and effective doses were calculated for scanograms and periapical radiographs. RESULTS: The effective doses for the scanograms were 0.001 mSv (central), 0.011 mSv (lateral) and 0.015 mSv (posterior). The effective doses for periapical radiographs were 0.001 mSv (anterior), 0.001 mSv (lateral) and 0.003 mSv (posterior) for rectangular collimation and 0.001 mSv (anterior), 0.002 mSv (lateral) and 0.005 mSv (posterior) for round collimation. CONCLUSIONS: When a larger area of the upper or lower jaw needs to be visualised, scanograms might be considered as an alternative to periapical radiography since the effective dose is lower.     

Papillary thyroid carcinoma metastasis to a branchial cleft cyst: a case report and review of imaging

Branchial cleft cysts are the most common lesions in the lateral neck with ectopic thyroid tissue found only rarely within these cysts. Over the years, multiple cases of papillary thyroid carcinoma arising from these ectopic thyroid tissues have been described in the literature with these cases sharing a normal thyroid gland on surgical and histological evaluation. Recently, however, there are three cases of papillary thyroid carcinoma in a branchial cleft cyst reported to be the result of metastasis from a thyroid primary. We present a 49-year-old female with a rare case of papillary thyroid carcinoma metastasis to a branchial cleft cyst with imaging characteristics that may prospectively suggest metastatic involvement.     

The thyroid and parathyroid glands. CT and MR imaging and correlation with pathology and clinical findings

Thyroid imaging approach is based on the preliminary clinical evaluation. Lesions that are smaller than 2 cm should be assessed with US, which is capable of discriminating masses as small as 2 mm and distinguishing solid from cystic nodules. US-guided FNAB provides tissue for cytologic examination of thyroid nodules. CT and MR imaging are indicated for larger tumors (greater than 3 cm diameter) that extend outside the gland to adjoining structures, including the mediastinum, and retropharyngeal region. Metastatic lymph nodes in the neck and invasion of the aerodigestive tract are also in the realm of CT and MR imaging. Thyroid nodules are categorized on scintigraphy as hot or cold nodules. Hot nodules are rarely malignant, whereas cold nodules have an incidence of 10% to 20% of malignancy. Calcifications (amorphous, globular, nodular, and linear) occur in adenomas and carcinomas and have no differential diagnostic features except for psammomatous calcifications, which are a pathognomonic finding in papillary carcinomas and a small percentage of medullary carcinomas. Papillary carcinoma is the most common malignant tumor (80%) followed by follicular (20% to 25%); medullary (5%); undifferentiated; anaplastic carcinomas (< 5%); lymphoma (5%); and metastases. Lymph node metastases are common in papillary carcinoma, 50% at presentation, and less common in follicular carcinomas. The metastatic nodes in papillary carcinoma may enhance markedly (hypervascular); show increased signal intensity on T1-weighted images (increased thyroglobulin content or hemorrhage); and reveal punctate calcifications. Localized invasion of the larynx, trachea, and esophagus occurs predominantly in papillary and follicular carcinomas; the incidence is less than 5%. Ectopic thyroid tissue may be encountered in the tongue (foramen cecum); along the midline between posterior tongue and isthmus of thyroid gland; lateral neck; mediastinum; and oral cavity. Goiter and malignant tumors, notably papillary carcinoma, may develop in ectopic thyroid tissue. Carcinomas may also arise in thyroglossal duct cysts, which develop from duct remnants between the foramen cecum and thyroid isthmus. Infectious disease of the thyroid gland is not common and the CT and MR imaging findings are similar as described under neck infection. Other types of inflammatory disorders including Hashimoto's thyroiditis, granulomatous thyroiditis, and Riedel's struma display no specific imaging features. Imaging studies may, however, be indicated to confirm a suspected clinical diagnosis and assess compromise of the airway (Riedel's struma). HPT is a clinical diagnosis in which hypercalcemia is the most important finding. Parathyroid hyperplasia, adenoma, and carcinoma represent underlying lesions. To relieve the patient's symptoms surgical extirpation is indicated. The surgical success rate without imaging is 95%. The indications for imaging studies vary but it is generally agreed that reoperation after a previous failed surgical attempt and suspicion of an ectopic parathyroid adenoma should be investigated by imaging. These consist of US, nuclear medicine studies, CT and MR imaging. US and technetium sestamibi scanning have the highest accuracy rate for localizing an adenomatous gland at and near the thyroid gland. Ectopic adenomas, particularly if they are located in the mediastinum, are preferrably investigated with CT and MR imaging with gadolinium and fat suppression. Carcinomas and parathyroid cysts are optimally evaluated by CT and MR imaging. On MR imaging adenomas are low in signal intensity on T1-weighted images, high in signal intensity on T2-weighted images, and enhance post introduction of gadolinium.     

Ectopic thymus presenting as neck mass

A 3-month-old girl presented with an asymptomatic soft tissue mass in the right neck. Her preoperative data were normal. CECT of the neck showed a 3-cm solid mass with homogeneous mild enhancement without mass effect. CECT of the thorax showed a normal thymus. MR images showed a right submandibular mass with signal intensity identical to that of the mediastinal thymus. Although it was difficult to make a correct preoperative diagnosis, surgical microscopic examination demonstrated normal thymic tissue. Because ectopic thymus can occasionally present with life-threatening symptoms, and malignant transformations have been documented, complete excision of cervical ectopic thymus was advocated.     

Radionuclide turnover studies on ectopic thyroid glands--case report and survey of the literature

A 72-yr-old woman who had previously undergone partial thyroidectomy for "toxic goiter" and subhyoid gland resection presented with signs and symptoms of ectopic lingual thyroid at the base of the tongue. The combination of lingual subhyoid and pretracheal thyroid is a rarity with only three cases reported. Discovery of ectopic thyroid tissue should raise suspicion of other ectopic thyroid tissues along the path of embryologic migration from its origin to the porta hepatis. This may necessitate assessment of radionuclide uptake and imaging of numerous areas. Sodium levothyroxine is the mainstay of therapy. In patients with obstructive symptoms, 131I ablation of the ectopic thyroid tissues has proven successful and may be more advantageous than surgery. In addition, radioiodide studies during ablation therapy gave new information that the ectopic lingual thyroid had more rapid iodide turnover compared with the postsurgical pretracheal thyroid gland.     

Normal variants and congenital anomalies in the region of the obelion.

A number of anatomic bony variants and several congenital anomalies are known to occur at the level of the obelion, that is, in the posterior interparietal region of the head, a short distance in front of the lambda. Among them are: (1) remnants of the embryonic parietal incisura, including parietal fissure, small and large parietal fontanelle, obeliac bones, persistant midline parietal foramen, and small and large parietal foramina; (2) encephalomeningoceles and related defects, including true encephaloceles, herniation of midline intracranial cysts (diencephalic and Dandy Walker cyst), epicranial arachnoid cysts, and scalp defects with ectopic glial tissue; and (3) congenital scalp and skull defects (cutis aplasia congenita). A review of these defects is presented with some illustrative examples not previously reported.     

Severe thyrotoxicosis caused by an ectopic intrathoracic goiter

The case of a 71-year-old woman with severe thyrotoxicosis due to an ectopic multinodular intrathoracic goiter is described. Previously reported cases with intrathoracic ectopic thyroid tissue were either nontoxic, or, if thyrotoxic, were a direct continuation of the tissue of the normally located gland. This mass was proved to be of thyroid origin using Tc-99m sodium pertechnetate scanning.     

Vascular retention of Tc-99m pertechnetate simulating ectopic or metastatic thyroid tissue

A Tc-99m pertechnetate thyroid scan performed post-operatively in a patient with Hashimoto's disease demonstrated an area of uptake that simulated either ectopic or metastatic thyroid tissue. Radionuclide angiography showed vascular retention of the tracer.     

False-positive result of a total-body scan caused by benign thyroidal tissue after I-131 ablation

This case report illustrates a false-positive result of an I-131 total-body scan caused by abnormal, noncancerous thyroid tissue. A 39-year-old woman underwent an open biopsy and thyroidectomy for a papillary thyroid carcinoma. She was treated by ablation with 150.8 mCi I-131. A follow-up total-body scan revealed a solitary focus of increased activity near the midline at the upper border of the larynx that was subsequently excised. Histologic analysis indicated a fragment of thyroid tissue with chronic inflammation, fibrosis, and squamous metaplasia. No evidence of thyroid carcinoma was present. Hypofunctioning or nonfunctioning residual tissue within the thyroglossal duct may have been suppressed under euthyroid conditions, protecting it from ablation. This tissue may have become stimulated by the high thyroid-stimulating hormone levels, accumulating I-131 and producing a false-positive result of the scan.     

Two cases of schwannoma with marked cystic changes

We report two cases of schwannoma displaying marked cystic changes; one in the temporalis muscle and one in the submandibular space. The first patient, a 44-year-old male, presented after complaining of a swelling rapidly increasing in size in the left temporal region. Computed tomography (CT) indicated a low-density area surrounded by soft tissue. Magnetic resonance imaging (MRI) revealed signal hypointensity on T1 weighted imaging and strong signal hyperintensity on T2 weighted imaging. The extirpated tumour specimen measured 58 mm x 58 mm x 30 mm. Histopathological examination identified schwannoma, comprising spindle cell proliferation in a palisading pattern with obvious cystic changes. The second case involved a 46-year-old female who presented with swelling of the right submandibular region. Panoramic radiography and lateral oblique mandible projection, which were used together with conventional sialography of the submandibular gland, revealed the so-called "ball in hand" appearance of the submandibular gland, and contrast-enhanced CT identified a lesion of 30 mm diameter with a well-defined annular margin and homogeneous low-density near the tumour centre. Benign pleomorphic adenoma was suspected, but histopathological examination identified schwannoma, predominantly comprising Antoni B type tissue.