-Case Reports-

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

Tomoo Jikuzono¹, Shigekazu Suzuki², Osamu Ishibashi^1,3, Shoko Kure⁴, Atsuko Sakanushi⁵, Munenaga Nakamizo⁶, Masashi Kawamoto⁷, Ryuji Ohashi⁴, Tetsu Yamada^1,8 and Iwao Sugitani¹

¹Department of Endocrine Surgery, Nippon Medical School, Tokyo, Japan
²Department of Cytology, Kanaji Thyroid Hospital, Tokyo, Japan
³Laboratory of Biological Macromolecules, Department of Applied Life Sciences, Graduate School of Life & Environmental Sciences, Osaka Prefecture University, Osaka, Japan
⁴Department of Integrated Diagnostic Pathology, Nippon Medical School, Tokyo, Japan
⁵Department of Otolaryngology, Head and Neck Surgery, Nippon Medical School, Tokyo, Japan
⁶Department of Otolaryngology, Tokyo Women's Medical University, Tokyo, Japan
⁷Department of Diagnostic Pathology, Shonan Fujisawa Tokushukai Hospital, Kanagawa, Japan
⁸Department of Endocrine Surgery, Kanaji Thyroid Hospital, Tokyo, Japan

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). Tracheal origin was confirmed postoperatively.
Case Description: A 77-year-old woman presented to our hospital with acute inspiratory dyspnea requiring emergency tracheotomy. Physical examination revealed swelling of the right anterior neck and a hard, immobile 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. We performed FNAC. Clinical findings were highly suggestive of ACCT with thyroid invasion. She underwent total laryngectomy, cervical esophagectomy, and thyroidectomy with bilateral selective neck dissection at another hospital. The tumor was located in the right posterior wall of the trachea and extended into the right thyroid gland. Pathological examination showed infiltrative carcinomatous proliferation with tubular and cribriform patterns. The tumor was classified as pT4N1. A definite diagnosis was made after histopathological analysis of the surgical specimen confirmed ACCT. The tumor was positive for FABP7, a putative prognostic marker of ACC, and metastasized to the lungs 3 years after 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.

J Nippon Med Sch 2022; 89: 460-465

Keywords
fine-needle aspiration cytology, adenoid cystic carcinoma, adenoid cystic carcinoma of the trachea, anaplastic thyroid carcinoma, fatty acid binding protein 7

Correspondence to
Tomoo Jikuzono, MD, PhD, Department of Endocrine Surgery, Nippon Medical School, 1-1-5 Sendagi, Bunkyo-ku, Tokyo 113-8602, Japan
t-jikuzono@nms.ac.jp

Received, December 28, 2020
Accepted, March 17, 2021