Hormone-Negative, Chromogranin a-Positive Endocrine Tumors

Abstract

THE overproduction of hormones by endocrine tumors contributes to their clinical manifestations and serves as the basis of diagnostic testing.1 We describe tumors of three different endocrine tissues — medullary thyroid carcinoma, anterior pituitary adenoma, and pancreatic islet-cell carcinoma — that did not produce their resident hormones (hormone-negative) but did produce chromogranin A (chromogranin A–positive). Chromogranin A is a 439-amino-acid protein encoded on chromosome 14 that is produced by a variety of normal and malignant neuroendocrine cells but not by non-endocrine cells.2 3 4 5 Chromogranin A is overproduced and released into the circulation by endocrine tumors and has consequently become a marker . . .