The oncocytic variant of papillary thyroid carcinoma with multifocal involvement: a case report

The oncocytic variant of papillary thyroid carcinoma is an uncommon form of neoplasm, the clinicopathological features and biological behavior of which have not been precisely defined. The pattern of multifocal growth is an uncommon feature. The case was a 64-year-old female patient with multinodular goiter who had undergone total thyroidectomy. Microscopic examination of cross-sections of the multiple nodules revealed a tumoral lesion characterized by a predominant follicular growth pattern, and sparse, small, abortive papillary structures. Most of the tumor cells also displayed the classical nuclear features of papillary carcinoma, like optically clear nuclei, overlapping of the nuclei, irregular nuclear membranes, and sparse nucleoli. Prominent nuclear grooves and intranuclear pseudoinclusions were seen in many of the neoplastic cells. Due to the presence of the characteristic nuclear features, the diagnosis was papillary carcinoma. The oncocytic variant of papillary carcinoma, although rare, appears to represent a morphologically distinctive variant of papillary cancer.