[Enviromental factors in the pathogenesis of thyroid cancer]

Local factors with a possible influence on the frequency and histological type of thyroid cancer are examined in the light of cases observed at the Mauriziano Hospital in the last 10 years. The overall number of cases has been increasing and papilliferous forms have been more common than follicular forms. Iodine deficiency and thyrotropin hyper-stimulation encourage onset and account for the higher frequency of thyroid cancer in endemic areas, where, however, follicular forms are more common. Ironising radiation is a direct cause, particularly of papilliferous forms arising after exposure during youth.