2019 Volume 58 Issue 6 Pages 249-255
Objective : The influence of the diagnostic criteria (Turin criteria) in the new WHO classification 4th edition (2017) on the cytological diagnosis of poorly differentiated carcinoma (PDC) was examined, focusing on the three findings that are prerequisite for the diagnosis (convoluted nuclei, necrosis and mitoses), as well as on the cytological differentiation from other thyroid tumors with the STI pattern.
Study Design : We reviewed 48 cases of PDC diagnosed between 2014 and 2017, and included FNA samples of 36 cases in which the cytological diagnosis is satisfactory for this study. The findings in the 36 cases were reviewed for rediagnosis according to the criteria, and the cases were divided into two groups based on the findings : the PDC group (n=17) and the non-PDC group (n=19) with a STI (solid, trabecular, insular) pattern, consisting of 15 papillary carcinomas and 4 follicular carcinomas. We compared the cytological features between.
Results : Hypercellularity, absence of colloid, the STI pattern, crowded clusters, dyscohesiveness, and increased N/C ratio were observed in both groups, but the incidence of uniformly small round nuclei and hyperchromasia was statistically significantly higher in the PDC group. The three prerequisite findings were not observed, except in one case.
Conclusion : The most frequently encountered findings in PDC mentioned above had been known since before, and the three prerequisite findings were absent in almost all cases. Consequently, the new WHO classification seems to have had limited impact on the cytological diagnosis.
