[Anaplastic carcinoma of the thyroid: early clinical and histopathological stages. Therapeutic implications (author's transl)].

Anaplastic carcinoma of the thyroid is generally considered a primary condition. Our study, based on ten observations, shows that anaplastic carcinoma of the thyroid with a rapidly fatal course may arise in long-standing goiters. Borderline histologic changes may be encountered; in some differentiated nodules, undifferentiated areas were found.