Histological and immunohistochemical profile of sporadic and familial medullary thyroid carcinoma

Abstract Introduction The histological and immunohistochemical profile of medullary thyroid carcinoma is ill-defined. The objective of this study was to determine the epidemiological, histological, and immunohistochemical characteristics of medullary carcinoma and to analyze whether differences exist between sporadic and familial carcinomas. Patients and methods Fifty-five histologically confirmed tumors were studied. Histological slides were reviewed and immunohistochemical staining of the archival paraffin blocks was performed. Results Nineteen of the 55 carcinomas (35%) were sporadic, and 36 (65%) familial. Sex distribution was similar, but familial carcinoma was more common in patients under 40 years of age ( p p Conclusions Familial cases were more frequent when there was more C-cell hyperplasia and multicentricity. Sporadic cases more frequently showed foci of necrosis, hemorrhage, vascular invasion, and neovascularization. Neither histopathological nor immunohistochemical criteria are useful for differentiating between familial and sporadic forms.