Statistical analysis of histomorphological findings in medullary thyroid carcinoma: distinction between the different familial forms of the disease. G.E.T.C. Groupe d'Etude des Tumeurs a Calcitonine.

A multifactorial analysis of morphological findings was performed on 153 cases of medullary thyroid carcinoma (MTC). The aim of the study was to utilize histological criteria to discriminate between MTC associated with multiple endocrine neoplasia type 2A (MEN 2A) and that associated with the inherited MTC only syndrome. The presence of fusiform cells associated with several other markers seemed to be more predictive of MEN 2A. A comparison of inherited MTC only and sporadic MTC only showed fusiform cells to be significantly less common in inherited MTC only. These results suggest that the inherited MTC only syndrome is a distinct clinical and morphological entity. Further investigations are needed to confirm the findings and understand its implications.