Cytomorphological changes after ultrasound-guided percutaneous ethanol injection in benign thyroid nodules

Abstract

To characterize the cytomorphological changes after percutaneous ethanol injection (PEI) in benign thyroid nodules, we compared the cytological features of fine needle aspiration cytology (FNAC) samples before and after PEI. Methods: Fifty-five cases diagnosed with adenomatous goitre (group 1, 35 cases) or cystic changes only (group 2, 20 cases) were included. In all cases, FNACs were performed by the pathologists before and after PEI. PEI was performed in all cases by a diagnostic radiologist according to the ultrasound guidelines. The following cytological features were evaluated by two pathologists: cellularity of follicular epithelial cells, background, cellular pleomorphism, nuclear/cytoplasmic (N/C) ratio, chromatin pattern, presence of nucleoli, macrophages, multinucleated giant cells, and mitosis. Results: In group 1, 19 cases (54%) showed changes in cellularity after PEI, with reduced cellularity in 13 cases (37%) and increased cellularity in six cases (17%). No necrotic background was observed before PEI; however, 14 cases (40%) developed necrotic background after PEI (P < 0.0001). Multinucleated giant cells were observed in 18 cases (51%) after PEI, which is in contrast to four cases (11%) before PEI (P = 0.001). In group 2, necrotic background was seen in 11 cases (55%, P < 0.0001) and multinucleated giant cells were observed in four cases (20%) after PEI. Conclusions: Necrotic background and presence of multinucleated giant cells are indicative of tissue damage caused by PEI in the FNAC specimens of benign thyroid nodules. In contrast to other modalities including chemotherapy or radiation treatment for malignant tumour, no unusual cytological change is observed after PEI. © 2008 Blackwell Publishing Ltd.