Introduction: Fine-needle aspiration (FNA) biopsy of Hürthle cell proliferations can be difficult to characterize based purely on morphologic features. Studies have shown Hürthle cell neoplasms often demonstrate gains in chromosomes 5, 7, and 12. This study examined fluorescence in situ hybridization (FISH) performance characteristics in non-neoplastic and neoplastic Hürthle cell proliferations sampled by FNA biopsy in order to assess chromosome patterns. Materials and methods: FNA biopsies of Hürthle cell proliferations, including nodular hyperplasia (NH), Hürthle cell adenoma (HCA), and Hürthle cell carcinoma (HCC), that had subsequent surgical excision were selected. FISH was performed on an air-dried, modified Wright-Giemsa–stained, aspirate smear slide from each case using a 3-color panel consisting of 1 subtelomeric and 2 centromeric probes for chromosomes 5, 7, and 12. Chromosomal probe patterns were recorded in up to 50 cells. A positive result was considered when >15% of cells showed a polysomy in 2 or more chromosomes. Results: A total of 25 cases were included in the study. All cases of NH were negative, and 7 of 9 (78%) HCAs and 8 of 12 (67%) HCCs were positive. Of the positive cases, 2 of the 7 (29%) HCAs showed >50% of cells with polysomy, and 5 of the 8 (63%) HCCs showed >50% of the cells with polysomy. Conclusion: Thyroid FNA biopsy can identify Hürthle cell proliferations; risk stratification based on morphology is difficult, however. FISH chromosomal evaluation of thyroid FNA biopsies is useful to distinguish neoplastic from non-neoplastic Hürthle cell proliferation.
- Fine-needle aspiration
- Fluorescence in-situ hybridization
- Hürthle cell