[Differentiated thyroid cancer. Their peculiarities in typing and assessment of invasiveness]

Differentiated thyroid carcinomas (follicular and papillary) were found to differ, for several biological behaviours, from carcinomas of other organs and even from anaplastic carcinomas of the thyroid. These peculiarities are quite often morphologically characterised by mature, organ-like histological appearances, long-time encapsulation from adjacent thyroid tissue, and delayed metastasation. Proper judgement of need for surgery and operability, consequently, can be quite difficult. Any tumour, therefore, should be individually assessed, and caution may be appropriate when it comes to therapeutic decision-making. These tumours are briefly typed in this paper by their histological patterns. The unique nature is mentioned of follicular and papillary carcinomas. Reference is made to factors of relevance to prognosis.