Neuroendocrine differentiation in follicle-cell thyroid carcinoma: correlation to prognostic factors in papillary carcinoma.

The presence of NE-differentiation in the follicle-cell thyroid carcinoma has been investigated by immunohistochemical detection of chromogranin A in the neoplastic cells. It has been found that NE-differentiation was present in a significant percentage in the papillary Ca alone (46.60%) whereas all Huerthle-cell neoplasms and the large majority of follicular and undifferentiated carcinomas showed non reactivity for Chromogranin A. Moreover, we have correlated the presence of NE-differentiation to well known prognostic factors in papillary Ca. We found a statistically significant correlation between the neuroendocrine differentiation and some unfavourable factors such as old age of the patient, size of the tumor, invasion of thyroid capsule and lymphnode involvement. We suggested that NE-differentiation could be considered as an index of poor prognosis.