Purpose <p>The inferior thyroid artery is an artery of the anterolateral neck and supplies blood to the thyroid gland and surrounding structures in the neck. Here, we report an anatomical variation of the left inferior thyroid artery in a male cadaver. We aimed to enrich the data on these anomalies, which can have implications for surgical interventions and clinical outcomes.</p> Case presentation <p>During routine neck dissection of a 64-year-old male donor, the inferior thyroid artery was identified bilaterally. On the left side, the inferior thyroid artery was absent and replaced by the thyroid IMA artery. The thyroid IMA artery formed a U-shaped course and gave branches to the lower part of the thyroid gland. In addition, the thyroid IMA artery arose from the brachiocephalic trunk. Furthermore, the branch of the thyroid IMA artery ascended parallel to the left recurrent laryngeal nerve. There was no anatomical variation of the right inferior thyroid artery.</p> Conclusions <p>The current study describes a significant anatomical variation as the absence of the left inferior thyroid artery compensated by the thyroid IMA artery. This variation has significant implications for clinical practice and surgical procedures, particularly for surgery in the neck, axilla, and superior mediastinum. Preoperative imaging and surgical panning should be considered to avoid the likelihood of complications during clinical practice and surgery.</p>