Document Type


Publication Date



A syndrome of ultimobranchial thyroid neoplasms which shares many similarities with medullary thyroid carcinoma in man occurs frequently in populations of adult bulls. The results of this investigation demonstrated that ultimobranchial neoplasms were composed of poorly differentiated parafollicular (C—) cells with extensive aggregations of microfilaments, clusters of ribosomes, and prominent Golgi apparatuses. Secretion granules often were interspersed between microfilaments. Other more columnar neoplastic cells assumed a ductal pattern. The prominent stroma contained amyloid fibrils and collagen fibers. By comparison, cells comprising medullary thyroid carcinoma were more differentiated parafollicular cells with well developed cytoplasmic organelles and numerous membrane‐limited secretion granules. Calcitonin activity was demonstrated by biologic assay in both ultimobranchial adenomas (466 ± 84 MRC mU/g) and carcinomas (409 ± 93 MRC mU/g) but serum calcium and phosphorus levels were within normal limits. Plasma calcitonin‐like activity was increased significantly 1 hour after calcium infusion but rapidly returned to baseline values. Parathyroid glands from bulls with ultimobranchial neoplasms had ultrastructural evidence of atrophy and secretory inactivity. Numerous lipofuscin, granules and cytosegresomes but few secretory granules were present in chief cells. Aggregations of amyloid fibrils surrounded chief cells and capillaries. Multiple endocrine tumors (pheochromocytomas and pituitary acidophil adenomas) and vertebral osteosclerosis with ankylosing spondylosis frequently were detected in bulls coincidentally with ultimobranchial thyroid neoplasms. Copyright © 1973 American Cancer Society

Publication Source (Journal or Book title)


First Page


Last Page