Bone abnormalities in patients with medullary carcinoma of the thyroid.

The frequency and appearance of bone abnormalities in patients with medullary carcinoma of the thyroid were compared with those of patients with other thyroid carcinomas. Only in patients with medullary carcinoma the following abnormalities were found: dolichocephaly, prognathism, anterior chest deformity, bone cysts. Schmorl nodes, spina bifida, slipped femoral epiphysis, pes cavus and marfanoid body build. Not only patients with medullary carcinoma of the thyroid as part of multiple endocrine neoplasia, but also patients with otherwise unrelated medullary carcinoma had bone defects. The cause of the bone abnormalities is probably a defect of a stem cell in the embryonal neural crest rather than a sustained effect on bone tissue of the tumor produced calcitonin.