Advanced Tracheal Adenoid Cystic Carcinoma with Thyroid Invasion Mimicking Thyroid Cancer Treated with Definitive Radiation: Case Report and Review of the Literature

Ultrasonographic findings of tracheal adenoid cystic carcinoma with thyroid invasion and mimicking thyroid tumors: a case report

Background

Tracheal adenoid cystic carcinoma (TACC) is a rare, low-grade malignant tumor. The primary TACC usually metastasizes to the lung and bone, rarely involving the thyroid. Although some previous reports have described the imaging features of TACC with thyroid invasion, the multimodal ultrasound findings of TACC with thyroid invasion and mimicking thyroid tumors have not been reported before.

Case Description

A 69-year-old woman who had been experiencing hoarseness for 2 years and a thyroid nodule for 2 months was presented to our clinic. Conventional ultrasound showed a hypoechoic nodule about 33×25×50 mm in the left lobe and isthmus of the thyroid, adjacent to the trachea and extending to the right lobe. Contrast-enhanced ultrasound (CEUS) showed that the nodule was unevenly enhanced, with iso-enhancement in the periphery and hypo-enhancement in most of the central area. Shear wave elastography showed that the maximum Young's modulus of nodules was 237.5 kPa, the minimum was 0.1 kPa, and the average was 60.5 kPa. Triiodothyronine, thyroxine, thyroid stimulating hormone and calcitonin were within the normal range. The patient underwent radical surgery with an uneventful postoperative recovery. Combined with the intraoperative findings and pathological examination, the diagnosis of TACC with thyroid invasion was made.

Conclusions

This rare case shows that TACC invading the thyroid may be manifested as a thyroid tumor on ultrasound. Preoperative pathological examination and comprehensive imaging examination are of great significance for the clinical management of patients. We also reviewed the literature on the imaging findings and clinical performance for TACC with thyroid invasion.

Radiotherapy for primary thyroid adenoid cystic carcinoma

Primary thyroid adenoid cystic carcinoma (PTACC) is an extremely rare type of mucin-secreting adenocarcinoma. Currently, it is difficult to diagnose, and it lacks standard treatment protocols. We report the case of a 53-year-old female patient with PTACC who underwent additional intensity-modulated radiotherapy 1 month after surgical treatment with an uneventful course. No invasion or distant metastasis was detected at the 7-month follow-up after radiotherapy, and the prognosis was favorable. In this case, herein, we have summarized the diagnostic features of the disease and proposed that postoperative adjuvant radiotherapy can significantly improve the patient's prognosis. Finally, we further confirmed the important role of radiotherapy in PTACC by reviewing relevant literature, which may provide clinicians with valuable treatment experience.

Clinical Utility of Fine Needle Aspiration Cytology for Adenoid Cystic Carcinoma of the Trachea with Thyroid Invasion: A Case Report

BACKGROUND

Adenoid cystic carcinoma of the trachea (ACCT) is a rare cancer; ACCT with thyroid invasion is particularly rare. We first suspected anaplastic thyroid carcinoma (ATC) but diagnosed ACC after performing fine needle aspiration cytology (FNAC). A tracheal origin was confirmed after operation.

CASE DESCRIPTION

We report the case of a 77-year-old female presenting to our hospital with acute inspiratory dyspnea requiring emergency tracheotomy. Physical examination revealed a right anterior neck swelling with a hard and unmovable mass. Computed tomography (CT) and ultrasonography (US) showed tumor extension to the right thyroid lobe, and between the first and third tracheal rings, which caused severe stenosis of the lumen. Next, we performed FNAC. Clinical findings were highly suspicious for ACCT with thyroid invasion. Thirty-five days after the first visit to our department, the patient underwent total laryngectomy, cervical esophagectomy, and thyroidectomy with bilateral selective neck dissections at another hospital. The tumor was located in the right posterior wall of the trachea, with extension into the right thyroid gland. Pathological examination showed an infiltrative carcinomatous proliferation with tubular and cribriform patterns. The tumor was classified as pT4N1. A definite diagnosis was made after histopathological analyis of the surgical specimen confirmed ACCT. The tumor was found to be positive for FABP7, a putative prognostic marker of ACC, and metastasized to the lungs 3 years after the surgery.

CONCLUSIONS

ACCT with thyroid invasion is an extremely rare malignant neoplasm. FNAC was useful for differentiating ACCT from other diagnoses and enabled appropriate surgical treatment.

Successful Development of a Competency-Based Residency Training Program in Radiation Oncology: Our 15-Year Experience from Within a Developing Country

One of the main challenges of delivering high quality of care to cancer patients in developing countries is the lack of well-trained radiation oncologists. This is a direct cause for the lack of residency programs coupled with lack of resources. This article describes and details establishments of a successful and sustainable radiation-oncology residency program in our country. The program has been in operation for 14 years and has trained and graduated radiation oncologists who are now working in various countries. The curriculum of the 4-year residency program, fashioned according to American College of Radiologists (ACR) recommendations, includes site-specific clinical rotations and didactic lectures in clinical oncology, radiobiology, medical physics, statistics, and epidemiology. It also includes a component of advanced clinical experience in the form of 3-month externship at one of collaborating centers outside the country. Evaluation of the residents is conducted annually via written exams and 360° feedback. Residents also sit for the formal certification exam in radiation oncology from the national Medical Council. The exam consists of 2 written exams and one oral. As a form of benchmarking residents' knowledge, they are required to sit for the ACR examinations held annually and conducted in Amman in tandem. The program has successfully trained and graduated 28 residents, who now work as consultant radiation oncologists locally and abroad. Each resident has gone through a structured training that includes exposure to a Western-style patient-management culture, enhancing the breadth and width of their clinical experience. The residency program, initiated in a developing country, underwent many challenges, yet it overcome all obstacles and resulted in a successful training of competent radiation oncologists serving the region.