A Primary Leiomyosarcoma of the Thyroid Gland: A Case and Literature Review

Introduction: We want to present a rare case of Primary leiomyosarcoma of the thyroid (PLT) gland and review the literature on PLT including the differential diagnoses, pathology, and alternative treatment strategies.Presentation of Case: A 56-year-old man who underwent left side total thyroidectomy with diagnosis of substernal goiter. On pathologic examination, three different pathology clinics had a common opinion that this was a grade 3 pleomorphic sarcoma of thyroid itself. Positron Emission Tomography (PET/CT) obtained one month after surgery displayed no distant metastases. Loco regional radiotherapy (RT) to the thyroid bed was delivered up to a dose of 59.4 Gray (Gy) in 1.8 Gy daily fractions. PET/CT obtained three months after RT showed bilateral multiple lung metastases without loco regional recurrence. The patient received 6 courses of doxorubicin and cyclophosphamide based chemotherapy. A new PET/CT scan showed only two metabolically active metastases on both lungs. Because of disappearance of small metastases, the patient underwent sequential bilateral metastasectomy in one month interval. Pathology results verified the metastases of PLT. The patient is still alive without any signs of disease 6 years after RT and he is the only long surviving case reported up to now.Conclusion: The treatment protocols for PLT have not been well established yet, because of their rareness and poor prognosis. We believe that our case may be directive for PLT treatment