Ultrasound diagnosis of C-cell carcinoma of the thyroid

Abstract

Ultrasound screening in 9 and 21 members, respectively, of two families affected by familial C‐cell carcinoma, as well as sonographic findings in 6 patients with sporadic medullary carcinoma of the thyroid (MCT), are reported. Unilateral and bilateral tumor nodules were identified by sonography in 12 of fl total of 13 patients with MCT (n = 9) or local tumor recurrence following thyroidectomy (n = 4); one carcinoma, 3 × 6 mm in diameter, was missed. Nine of the 12 (75%) were clinically occult, nonpalpable C‐cell carcinomas. The smallest occult MCT correctly diagnosed by ultrasound had a diameter of 4 mm. A positive correlation was found between the sonographically determined tumor mass (number/size of nodules/metastases) and the plasma calcitonin level. Pheochromocytomas were diagnosed by ultrasound as part of a multiple endocrine neoplasia (MEN IIa) in two patients with MCT. The echomorphologic findings of the intrathyroid C‐cell carcinomas and their metastases display characteristic but nonspecific features. Sonographic findings on these tumors should therefore not be interpreted without consideration of plasma calcitonin assays.