Abstract
Primary thyroid lymphomas are pretty uncommon, and constitute about 5% of the neoplasms of this organ. Spontaneous tumor regression is defined as the total or partial disappearance of a tumor as proven by microscope without treatment or under inadequate treatment. It is estimated to happen in one out of 60,000-100,000 cases. We present a case of primary thyroid lymphoma with spontaneous regression after diagnostic puncture and corroborated with hemithyroidectomy at four months. The patient died after twenty-six months of follow-up because of endocarditis and there was no relapse at any time.