Is atypical follicular adenoma of the thyroid a preinvasive malignancy?

• Published in: Human pathology Vol. 34; no. 7; pp. 666 - 669
• Main Authors: Tzen, Chin-Yuan, Huang, Yu-Wen, Fu, Yao-Shi
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.07.2003; Elsevier Limited
• Subjects: Adenocarcinoma, Follicular - genetics; Adenocarcinoma, Follicular - pathology; Adenoma - chemistry; Adenoma - genetics; Adenoma - pathology; atypical adenoma of thyroid; Biomarkers, Tumor - analysis; Cancer; Diagnosis, Differential; DNA Mutational Analysis; DNA Primers - chemistry; DNA, Neoplasm - analysis; Genes, p53 - genetics; Humans; Immunohistochemistry; Mutation; p53 mutation; Point Mutation; Polymerase chain reaction; Precancerous Conditions - genetics; Precancerous Conditions - pathology; Thyroid cancer; Thyroid gland; Thyroid Neoplasms - chemistry; Thyroid Neoplasms - genetics; Thyroid Neoplasms - pathology; Tumor Suppressor Protein p53 - chemistry; Tumor Suppressor Protein p53 - genetics; Tumors; p53 mutation; PCR; atypical adenoma of thyroid
• ISSN: 0046-8177; 1532-8392
• DOI: 10.1016/S0046-8177(03)00241-7

Among the follicular neoplasms of the thyroid, the definition and nature of atypical adenoma have been confusing. Despite the original speculation about the biologic behavior of preinvasive malignancies, this term is currently used as an expression of uncertainty. To examine the molecular features of a typical adenoma, we analyzed the p53 genes in 2 atypical adenomas and 12 control lesions (6 typical follicular adenomas and 6 follicular carcinomas). Mutations of p53 were detected in the bizarre cells of the atypical adenomas, but not in the bland-looking follicular cells or in the control specimens. Both atypical adenomas showed an identical point mutation in codon 273 (CGT→CAT), a common mutation in various human cancers, including anaplastic carcinoma of the thyroid. This finding supports the view that atypical follicular adenoma is a precursor of thyroid anaplastic carcinoma and suggests that “atypical adenoma” should not be used to express diagnostic uncertainty about the nature of a lesion.