Histological Typing of Thyroid Tumours - libdoc.who.int - World ...

Introduction
Knowledge of tumours of the thyroid gland has advanced considerably
in the 22 years that have elapsed since work was started on the
first edition of Histological Typing of Thyroid Tumours.In the introduction
to that volume it was recognized that the dehnitions and classifrcations
put forward would need revision in time, and the present
text differs substantially from the first edition. As far as is possible,
however, the framework of the classification proposed remains the
same, as the original classification was widely accepted and proved
useful in many studies.
The link between the morphological type of thyroid tumour and
its epidemiology, natural history function, prognosis and response to
therapy has been further strengthened since the first edition. In particular,
the decision taken to separate papillary and follicular carcinomas
and exclude a mixed papillary follicular type has been well justified.
One of the major changes has been the recognition that many tumours
regarded 20 years ago as small cell carcinoma were really malignant
lymphoma, and this development has been incorporated into
this edition, with increased importance given to primary malignant
lymphoma of the thyroid. Much work has also been done on medullary
carcinoma of the thyroid, its link with multiple endocrine neoplasia
syndromes, and its association in its inherited form with C-cell
hyperplasia; this too is recognized by an expanded section on this tumour.
Otheq less frequent types of thyroid tumour have been more
clearly delineated during the last 20 years; when there is sufficient
evidence that the morphological type of tumour described is linked to
a difference in clinical behaviour it is referred to in this volume.
A major change in the management of thyroid tumours over the
last 20 years has been the introduction in many centres of fine-needle