Key Clinical MessageThe presented primary thyroid leiomyosarcoma (TL) case report underscores the importance of recognizing and addressing the diagnostic challenges and management complexities associated with this exceedingly rare malignancy. Given the limited effective therapeutic strategies available, timely intervention, thorough diagnostics, and vigilant follow‐up are paramount in managing such intricate tumors. Further research focusing on molecular‐based treatment modalities is imperative to improve patient outcomes in cases of primary TL.