Primary Thyroid Leiomyosarcoma: A Case Report

Introduction The thyroid's primary leiomyosarcoma (LMS) is an extremely rare type of soft tissue sarcoma arising from the thyroid capsule's vessel cells. The incidence of this tumour worldwide is unknown. And we have found only 28 cases of primary LMS published on the Pubmed platform between 1970 and 2024 [1–28] . LMS mainly presents in elderly patients as a growing mass in the neck. LMS prognosis is poor despite aggressive treatment with an estimated 5 months median survival time [25] . Case Presentation A 78-year-old female presented to the endocrinologist complaining of pressure and discomfort in her neck, dyspnea, general weakness, a dry cough, and numbness in the hands. Upon physical neck examination, the thyroid gland was enlarged and firm with a palpable ~5,0 cm node in the right lobe. Thyroid ultrasonography revealed a significantly enlarged right lobe with a hypoechogenic, heterogeneous nodule calcified on its edges, measuring 4,3x3,3x5,0 cm. Fine-needle biopsy results confirmed a malignant process. Chest X-ray revealed multiple irregularly shaped lesions, resembling metastases. Chest and abdominal CT confirmed multiple metastatic lesions in the lungs and an enlarged thyroid right lobe extending into the mediastinum. A total thyroidectomy was performed. Histopathology and immunohistochemistry analysis showed a tumour infiltrating the entire right lobe and adjacent soft tissues, consisting of atypical cells and areas of necrosis. Immunochemical staining revealed positive vimentin and SMA immunomarkers; These findings determined the diagnosis of primary LMS, pT3 N1 M1 Rx, G3. The patient was referred for adjuvant chemotherapy and put on hormone replacement therapy. Unfortunately, the patient passed away 3 months after the final diagnosis. Discussion Some studies show that LMS accounts for less than 0.014% of primary thyroid malignancies [8,25,27,29] . Preoperative diagnostics is challenging as LMS lacks distinctive imaging features that could aid in a definitive diagnosis[ 30]. However, most literature data suggest radical operative treatment, and the newest research in immunotherapy may prove effective. Conclusions Primary thyroid leiomyosarcoma is extremely rare type of thyroid cancer with complex preoperative diagnostics and poor prognosis. The gold-standard treatment approach remains undefined.