Clinicopathological and molecular features of 25 cases of the oncocytic carcinoma of the thyroid / 临床与实验病理学杂志

ABSTRACT

Purpose To investigate the clinicopathological and molecular genetic features of oncocytic carcinoma of the thy-roid(OCA).Methods The clinicopathological and immuno-histochemical data of 25 patients with oncocytic carcinoma of the thyroid were retrospectively reviewed.Genetic features were determined by fluorescence quantitative PCR.Results The male to female ratio of the 25 patients was 1 ∶ 1.8,and the aver-age age was 49 years.The tumor was confined to the thyroid gland.Of the 22 cases with a single nodule,5 cases were ill-de-marcated and 3 cases were multiple nodular lesions.The average size was 2.7 centimeter in diameter.Cytologically,the tumor cells were arranged in detached clusters with abundant eosino-philic and granular cytoplasm and hyperchromatic nuclei with prominent nucleoli.Histologically,the oncocytic tumor cells mainly arranged in trabecular and solid architecture.Capsular,blood and lymphoid vascular invasion could be observed in a cer-tain extent.Among 25 cases of OCA,8 cases were minimally in-vasive,14 cases were encapsulated angio-invasive and 3 cases were widely invasive.Positive immunoreaction with TTF-1,thy-roglobulin and CD56 supported the thyroid epithelial origination of the tumour.One recurrent case was found to have cervical lymph node metastasis,and another case was presented with bone metastasis,which was determined to harbor TERT promoter mu-tation(C228T)in each case.Different point mutation of RAS gene was determined in 2 cases(8%),respectively.Conclu-sion Oncocytic carcinoma of the thyroid shows typical eosino-philic and granular cytoplasm,immunohistochemical staining is helpful in differential diagnosis with other oncocytic lesions.It lacks BRAF-like mutation.Low frequency of RAS mutations could be found.Rare TERT promoter mutation has significant mutation with clinical behavior of OCA.