Physiologic versus neoplastic C-cell hyperplasia of the thyroid: Separation of distinct histologic and biologic entities

Abstract

Physiologic and neoplastic CCH are biologically and morphologically distinct entities. The former cannot be recognized with certainty with conventional stains and requires immunohistochemistry and quantitative analysis for diagnosis. The latter consists of mildly to moderately atypical C-cells that can be identified with H & E stained sections. Consequently, the number of C-cells is of no importance for the diagnosis of neoplastic CCH which is considered to be the precursor (medullary carcinoma in situ) of invasive medullary carcinoma.