Primary ectopic substernal thyroid cancer with trachea relapse: a case report and opinions of management

Primary Intrathoracic Ectopic Papillary Thyroid Carcinoma, Presenting With Thoracic Spine Metastasis: A Case Presentation and Literature Review

Thyroid cancer in ectopic thyroid tissue is a very rare entity. We report a patient with papillary thyroid cancer arising from upper mediastinal ectopic thyroid tissue. The patient presented with thoracic spine metastasis with cord compression. The patient was a 67-year-old woman, who presented with upper back pain. Magnetic resonance imaging (MRI) showed suspected metastatic disease in the second and third thoracic vertebrae (T2 and T3). She underwent laminectomy and decompression surgery at the T1-T3 level. The final pathology report showed metastatic thyroid carcinoma with papillary features. She underwent external beam radiation to the affected spine. Computerized tomography (CT) scan of the chest, abdomen, and pelvis showed a 3.0 × 2.8 × 2.3 cm soft-tissue mass in the left superior mediastinum extending into the supraclavicular region. Fluorodeoxyglucose-positron emission tomography (FDG-PET) scan showed hypermetabolic foci in the upper mediastinum. Fine needle aspiration (FNA) of the upper mediastinal mass was consistent with papillary thyroid cancer. Molecular testing from the FNA sample using Thyroseq V3 showed SQSTM1NTRK3 chromosomal rearrangement. A total thyroidectomy was performed. Pathology of the resected thyroid was benign. Pathology of the mediastinal mass showed a papillary thyroid carcinoma with focal tall cell features, forming a 4 × 2.5 × 2.5 cm mass. Surgery was followed by ablation with 100 millicuries (mci) of radioactive iodine (I-131) and external beam radiation. This case highlights the presentation of primary intrathoracic papillary thyroid cancer with SQSTM1-NTRK3 chromosomal rearrangement and the challenges in the diagnosis and management of this unique case. This patient had a very aggressive disease presentation that required multimodal treatment, including thoracic spine decompression, total thyroidectomy, primary intrathoracic goiter resection, high-dose radioactive iodine treatment, and external beam radiation to the affected spine area. SQSTM1-NTRK3 chromosomal rearrangement can be targeted by medications such as larotrectinib and endtrectinib.

Diagnosis and treatment of ectopic thyroid carcinoma: A case report and literature review

INTRODUCTION

Ectopic thyroid cancer (ETC) is primary thyroid cancer occurring in ectopic thyroid tissue, and its incidence rate is approximately 0.3%-0.5% of thyroid cancer. Only approximately 132 cases of ETC have been diagnosed and treated worldwide in the past 110 years, with most of them being adults. Of note, patients with ETC are prone to misdiagnosis and mistreatment.

CASE REPORT

This was a 13-year-old adolescent female who reported having a sensation of swallowing obstruction when eating blocky foods. Color Doppler Ultrasound (CDU) found a 2.3 cm ×1.7 cm × 2.1 cm hypoechoic nodule slightly to the right of the deep surface of the tongue base, with a honeycomb shape. Meanwhile, a mixed echogenic nodule of approximately 2.0 cm × 1.9 cm × 2.3 cm was seen deep in the mouth floor, and a very low echogenic region of 1.4 cm × 1.1 cm × 1.8 cm was observed in the nodule. We then performed a fine needle aspiration biopsy (FNAB) of the thyroid nodules guided by CDU, and the results showed papillary thyroid carcinoma (PTC). Then, a local extended resection of the thyroid carcinoma was performed. Bilateral cervical IA and adjacent subhyoid lymph node dissection was performed through a small anterior cervical incision. The patient recovered well, and was discharged on the fifth day after surgery. The patient only took levothyroxine tablets for replacement therapy after surgery. The patient was followed up for 36 months, and the thyroid function remained in the normal range. Reexamination by CDU showed no tumor recurrence, lymph node enlargement, or obvious change in the tongue base ectopic thyroid.

CONCLUSIONS

ETC is an extremely rare type of thyroid cancer, which is easy to be misdiagnosed. Preoperative use of CDU, nuclide scanning, computed tomography (CT)/Magnetic resonance imaging (MRI), and FNAB can significantly reduce the misdiagnosis rate of this disease. Surgery is currently the main treatment for ETC. Complete resection still has a high cure rate. For patients with advanced ETC who cannot be completely resected, external radiotherapy and targeted therapy can be tried, but the prognosis needs to be verified with more cases in the future.

The value of scintigraphy, computed tomography, magnetic resonance imaging, and single-photon emission computed tomography/computed tomography for the diagnosis of ectopic thyroid in the head and neck: A STROBE-compliant retrospective study

Because of its rarity, the exact imaging features of ectopic thyroid are poorly known.To analyze the value of scintigraphy, computed tomography (CT), magnetic resonance imaging (MRI), and single-photon emission computed tomography (SPECT)/CT in the diagnosis of ectopic thyroid in the head and neck.First, we retrospectively analyzed the scintigraphy, CT, MRI, and SPECT/CT images from 25 masses (22 patients) suspected of head and neck ectopic thyroid from 2006 to 2017 at the Shanghai Ninth People's Hospital. Each mass was imaged by nuclear imaging (scintigraphy with or without SPECT/CT) and radiological exam (CT and/or MRI). Pathological examination was considered as the gold standard. Secondly, thirteen malignant ectopic thyroids in the head and neck reported in the English literature from 2001 to 2017 were retrieved for comparison.The accuracy of scintigraphy was not significantly higher than that of CT (94.7%, vs 89.5%, P > .99) or MRI (92.3%, vs 84.6%, P > .99). Five masses which underwent scintigraphy with SPECT/CT were all true positive, while 1 was false negative on MRI, and 2 were false negative on CT. Compared to the benign ectopic thyroids in our study, the 13 malignant ectopic thyroids retrieved from the literature were grossly the same in shape, margins, and invasion on CT or MRI.The number of patients was limited, but scintigraphy combined with SPECT/CT could be a reliable method for the diagnosis of ectopic thyroid. Benign and malignant ectopic thyroids appear to be similar in shapes, margins, and invasion on CT or MRI.