C-Cell Hyperplasia Preceding Medullary Thyroid Carcinoma

TLDR

Two sisters and a third patient at risk for hereditary medullary carcinoma, each with progressive serum calcitonin elevations, were studied. The authors examined C‑cell distribution within the thyroid glands. The middle and upper lateral lobes showed marked C‑cell clustering with calcitonin levels of 670–4100 mU/g, far above normal (<0.6–50.0 mU/g), correlating with cytology and indicating a preinvasive hyperplastic process and multicentric, anatomically restricted hyperplasia in hereditary predisposition. Published in N Engl J Med 289:437–441, 1973.

Abstract

Two sisters at risk for hereditary medullary carcinoma and having small but progressive increases of serum calcitonin in response to calcium infusion underwent thyroidectomy. The thyroid glands were studied for C-cell distribution. Middle and upper portions of the lateral thyroid lobes showed marked increases and clustering of calcitonin-containing cells in comparison with normal thyroid glands. Elevated calcitonin content (670 to 4100 Medical Research Council mU per gram), as compared to similar regions in normal thyroid tissue (<0.6 to 50.0 Medical Research Council mU per gram), correlated precisely with the cytologic localization. Histologic characteristics of the cells had the appearance of a preinvasive hyperplastic process. A third case from another kindred was studied with similar findings. C-cells thus appear to be distributed inhomogeneously in normal human thyroid tissue; an early change in persons destined to development of hereditary tumors of these cells is a multicentric, but anatomically restricted, increase in numbers of cells. (N Engl J Med 289:437–441, 1973)