Thyroid Papillary Carcinomas with Extensive Calcification and Bone Metaplasia: A Clinicopathological Analysis of 41 Carcinoma Cases and Comparison with Benign Cases with Extensive Calcification and Bone Metaplasia

Abstract

Background and Objectives : The aim of the present study was to investigate the clinicopathological characteristics and implications of papillary carcinoma with extensive calcification and bone metaplasia (PTCECB), and to determine the differences between PTCECB and benign nodules with calcification and bone metaplasia (BNECB).

Materials and Methods : We retrospectively reviewed the slides of 41 PTCECB cases and 30 BNECB cases.

Results: Only four (9.8%) cases of PTCECB demonstrated psammoma bodies. Twenty eight (68.3%) cases of PTCECB showed prominent follicular architectures with occasional bland-appearing thyrocytes showing diffuse immunohistochemical expression for CK19 and galectin-3. All BNECBs revealed expanding tumor margins and were intrathyroidally located. In contrast, PTCECB showed expanding tumor margins in 26 (63.4%) cases (p=0.001) and extrathyroidal extension in 20 (48.8%) cases (p=0.000).

Conclusion:PTCECB showed characteristics of prominent follicular architecture and an absence of psammoma bodies and should be differentiated from BNECB by histological features such as extrathyroidal extension and characteristic nuclear features of papillary thyroid carcinoma combined with immunohistochemical study such as CK19 and galectin-3.