C-cell nodules in adult human thyroid. A common autopsy finding.

This study was designed to examine the morphologic features and distribution of calcitonin-producing cells (C-cells) in normal adults and in a general autopsy population. Random or serial sections from thyroid glands in forensic and general autopsies were examined by an immunoperoxidase stain for calcitonin to identify C-cells. Six glands out of 30 cases contained large C-cell nodules (85-343 C-cell nuclei per nodule). Five of the nodules were in patients over 50 years of age. C-cell nodules in thyroid sections may represent age-related hyperplasia or a normal variation of ontogeny. This study underscores the importance of serially sectioning the thyroid to evaluate nodular C-cell hyperplasia in preneoplastic or nonneoplastic functional disorders.