Jantima TanboonPhawin KeskoolMahidol University2018-10-192018-10-192013-09-01Endocrine Pathology. Vol.24, No.3 (2013), 136-14315590097104639762-s2.0-84883489191https://repository.li.mahidol.ac.th/handle/123456789/31226Primary leiomyosarcoma of the thyroid gland is uncommon. To date, 20 cases have been reported in English in the literature. The tumors usually present in elderly patients with female predilection and are associated with poor clinical outcome. Herein, we report an additional case of primary thyroid leiomyosarcoma in a 64-year-old woman. She underwent total thyroidectomy and later was discovered to have multiple lung and liver metastases. The patient died 3 months after surgery. The major differential diagnoses including undifferentiated (anaplastic) carcinoma of the thyroid, spindle cell variant of medullary thyroid carcinoma, spindle cell tumor with thymus-like differentiation, uncommon primary tumor of the thyroid and metastatic tumors with predominant spindle cells are discussed. © 2013 Springer Science+Business Media New York.Mahidol UniversityBiochemistry, Genetics and Molecular BiologyMedicineArticleSCOPUS10.1007/s12022-013-9251-1