[Poorly-differentiated thyroid carcinoma: morphological verification and differential diagnosis]

Poorly-differentiated thyroid carcinoma is a stage in the development of anaplastic carcinoma from well-differentiated neoplastic transformation of follicular epithelium. Such tumors differ with respect to histological pattern and age. For instance, patients, aged 50 and more, revealed great nodular size (50-70 mm), marked invasion, large cells with high mitotic index and solid and/or insular pattern. In the group under 40, incapsulated poorly-differentiated tumors were more frequent; they had trabecular histological pattern alone with a much smaller size (ca. 30mm). Further clinico-morphological studies might solve the problem of the connection between cyto- and histological pattern, on the one hand, and clinical course and prognosis, on the other.