ABSTRACT
According to the WHO classification from 2017, rare tumors of the thyroid can be classified into two groups as epithelial and non-epithelial tumors. Squamous cell carcinoma, mucoepidermoid carcinoma (MEC), sclerosing MEC with eosinophilia, mucinous carcinoma, ectopic thymoma, spindle epithelial tumor with thymus-like differentiation and intrathyroid thymic carcinoma are rare epithelial tumors. Non-epithelial tumors are paraganglioma, peripheral nerve sheath tumors, benign vascular tumors, angiomyosarcoma, smooth muscle tumors (leiomyoma – leiomyosarcoma) and solitary fibrous tumor. In addition, hematolymphoid tumors, germ-cell tumors, secondary tumors are other rare tumors. They are very rare tumors, all of which exhibit different biological behavior. In this chapter, we tried to concentrate on most rare tumors of the thyroid (1, 2).
