Cytomorphologic Spectrum of Hurthle Cell Lesions of Thyroid: A Study of 54 Cases.

Introduction: Lesions of the thyroid gland composed of Hurthle cells constitute a wide spectrum of pathological entities ranging from benign hyperplastic nodules with Hurthle cell metaplasia at one end to malignancies like Hurthle cell carcinomas. The cytological distinction of these entities is not only diagnostically challenging but are also critical since they influence treatment decisions.

Aim: To critically analyze the cytomorphology of cases of Hurthle cell lesions in FNACs and to characterize cytological features shown to be statistically signific ant in predicting Hurthle cell neoplasm (HCN).

Methods: During the period from January 2014 to August 2015, 1667 cases of thyroid FNAs were done at our centre, of which 54cases,showed a predominance of hurthle cells, i.e. more than or equal to 50% hurthle cells (≥=50%).These cases were included in the study and were critically reviewed for 9 cytomorphologic features which included cellularity, architecture, and percentage of Hurthle cells, background colloid, chronic inflammation, nucleoli, intranuclear cytoplasmic inclusions (INCI), nuclear grooves and transgressing blood vessels (TBV). The results were evaluated by using univariate and stepwise logistic regression (SLR) analysis; statistical significance was achieved at P-value < 0.05.

Results: Out of the 9 parameters studied, the cytological features shown to be statistically significant in predicting HCN and distinguishing them from benign hurthle cell lesions(BHCLs) were increased cellularity, non-macro follicular architecture, >90% Hurthle cells, absence of background colloid and absence of chronic inflammation.