Aspects échographiques des métastases hépatiques des cancers médullaires de la thyroïde

Purpose: The aim of this study was to describe the different ultrasonic features of hepatic metastases of medullary thyroid carcinoma and to point out two particular patterns. Material and Method: A retrospective review of the sonographic examinations of 35 patients with hepatic metastases from medullary thyroid carcinoma was performed. The metastases were classified relatively to their size and sonographic appearence. Results: Four ultrasonic types of metastases were described: Type I: small (<3 cm) hyperechoic nodules with the same features as typical hepatic hemangioma (54%); Type II: markedly hyperechoic micronodules often associated with acoustic shadowing (40%); Type III: hyperechoic nodules of more than 3 cm in diameter (14%) corresponding to advanced intrahepatic disease; Type IV: hypoechoic or in target form nodules (28%) rarely isolated (8%), mostly associated with additional hyperechoic lesions (20%). Thirty two out of 35 patients had hyperechoic nodules; in 22 patients the HM were of a single type, mainly type I (n = 12) and in 13 patients different types of nodules were present. These sonographic features were correlated with the histologic characteristics of medullary thyroid carcinoma. No precise relationship could be establish between the histologic form of MTC and the US features. Conclusion: The authors underline the possible mistake between the metastases of type I and the hemangioma and the characteristic appearance of metastases of type II.