Systemic amyloidosis is one of the serious complications of Familial Mediterranean Fever (FMF). Amyloid accumulation secondary to FMF can cause pressure symptoms in thyroid gland rarely. A 17-year-old male patient with the diagnosis of FMF performed the complaints of dyspnea during his follow-up period. He has demonstrated a rapidly increasing mass localized in front of his neck within the last three months that was diagnosed as a diff use, hyperplasic and pressuring thyroid gland. Total thyroidectomy was performed.

Histopathological investigation of the material obtained aft er thyroidectomy revealed diff use lipid infiltration in parenchyma, intense amyloid accumulation around and between the follicles that caused pressure on the follicles, and cystic areas in the tissue. Squamous metaplasia foci in cyst epithelium were detected. Upon these findings the case was diagnosed as amyloid goiter accompanied by metaplastic variations. In conclusion, it can be appropriate to take into account the possibility that metaplastic variations could accompany amyloid goiter in patients with long-term FMF.