Thyroid Lymphomas are rare tumors among thyroid neoplasms. Almost all types originate from B cells and the most frequent subtype is a diffuse large cell lymphoma. The majority arise in a background of Hashimoto's thyroiditis and patients present with a thyroid mass, rapidly enlarging and with pressure symptoms. The treatment depends on the histological subtype and stage of the disease but include radiotherapy and/or chemotherapy. The prognosis usually is favorable. The reported case presents a thyroid lymphoma. We discussed the clinic, diagnosis and treatment.