Aggressive Variants of Follicular Cell Derived Thyroid Carcinoma
Aggressive Variants of Follicular Cell Derived Thyroid Carcinoma
The pathological diagnoses and classification schemes for thyroid carcinoma have changed over the past 20 years and continue to do so. New entities have been described and molecular analyses have suggested better characterisation and grouping of certain tumours. Because some of the lesions have been named differently by different authors, clinicians and patients may be confused as to what a specific patient's lesion represents. In this review, we discuss the thyroid tumours of follicular origin which are clinically unusual but important to recognise as their behaviour may be aggressive, they may not respond to radioiodine treatment and they may cause significant mortality. This paper describes these important but rare lesions, their pathological features, important clinicopathological correlations, molecular correlates and prognostic implications.
The incidence of thyroid carcinomas is increasing globally; in 2012 it is expected to be the fifth leading cancer in women in the USA. As per National Cancer Institute data, there will be an estimated 56 460 new cases and 1780 deaths from thyroid cancer in 2012 in the USA. The recent literature on thyroid carcinoma has included many studies on clinical features, pathological subtypes and molecular characteristics. Some pathological studies have added confusion to the literature by classifying certain tumours with different names (eg, insular carcinoma, poorly differentiated carcinoma). In addition, new terminology has been suggested for certain thyroid cancers ('hobnail', 'micropapillary' carcinoma (the latter being different from papillary microcarcinoma!)). Finally, the pathological classification of follicular patterned tumours of the thyroid has caused confusion among clinicians and patients; the degree of interobserver variability has added to this problem.
In this paper, we review the types of thyroid carcinoma which are associated with aggressive clinical behaviour and list the pathological features of importance to aid in the classification. The implications of these tumours are discussed.
Abstract and Introduction
Abstract
The pathological diagnoses and classification schemes for thyroid carcinoma have changed over the past 20 years and continue to do so. New entities have been described and molecular analyses have suggested better characterisation and grouping of certain tumours. Because some of the lesions have been named differently by different authors, clinicians and patients may be confused as to what a specific patient's lesion represents. In this review, we discuss the thyroid tumours of follicular origin which are clinically unusual but important to recognise as their behaviour may be aggressive, they may not respond to radioiodine treatment and they may cause significant mortality. This paper describes these important but rare lesions, their pathological features, important clinicopathological correlations, molecular correlates and prognostic implications.
Introduction
The incidence of thyroid carcinomas is increasing globally; in 2012 it is expected to be the fifth leading cancer in women in the USA. As per National Cancer Institute data, there will be an estimated 56 460 new cases and 1780 deaths from thyroid cancer in 2012 in the USA. The recent literature on thyroid carcinoma has included many studies on clinical features, pathological subtypes and molecular characteristics. Some pathological studies have added confusion to the literature by classifying certain tumours with different names (eg, insular carcinoma, poorly differentiated carcinoma). In addition, new terminology has been suggested for certain thyroid cancers ('hobnail', 'micropapillary' carcinoma (the latter being different from papillary microcarcinoma!)). Finally, the pathological classification of follicular patterned tumours of the thyroid has caused confusion among clinicians and patients; the degree of interobserver variability has added to this problem.
In this paper, we review the types of thyroid carcinoma which are associated with aggressive clinical behaviour and list the pathological features of importance to aid in the classification. The implications of these tumours are discussed.