Familial medullary carcinoma of the thyroid through 3 generations.

A family with high genetic penetrance of medullary carcinoma of the thyroid was reported. Seven proven (6 patients and one autopsy case) and 2 probable cases of medullary carcinoma were present in 25 members through 3 generations. An endogemy had intervened in the prior generation of these cases. Preliminary results in clinicopathological examinations of 7 proven cases were as follows; clinically, all of the cases showed B type blood group. Glycosuria was found in 2 cases, and diarrhea in one case. Serum thyrocalcitonin being estimated in two cases showed high levels. The autopsy cases coexisted with medullary carcinoma of the thyroid and pheochromocytoma of the right adrenal. Pathologically, the majority of tumors occurred in both thyroid lobes, and were present from the middle to upper portion of the thyroid. The tumor showed a variety of histological features even in the same tumor. In the tumor cell, numerous membrane-limited granules were seen with an electron microscope. Amyloid was demonstrated only in the tumor tissue.