Abstract: Follicular carcinoma constitutes about 5 to 10 percent of thyroid cancers. It is characterized by the formation of more or less well-developed acini or follicles. We persent a case of follicular carcinoma with histological features of extensive nesting pattern and eosinophilic hyaline material deposition, resembling medullary thyroid carcinoma. However, the lesion consisted of thyroglobulin-positive and calcitonin-negative cells. This case illustrates the contribution of the immunohistochemical studies to the detection of the exact nature of thyroid tumors.
