Aneusomy is an early genetic event and a characteristic feature of many solid tumors. It is often associated with poor prognosis in cancer patients. The involvement of PAX8-PPARγ rearrangement in tumorigenesis of follicular thyroid lesions has been widely assessed. However, there were few reports on aneusomy of the PPARγ gene at the 3p25 locus in follicular thyroid lesions. It remains undetermined whether these abnormalities can be translated into improved diagnosis, classification, or outcome prediction. Herein, we report three cases of follicular thyroid neoplasms [two follicular thyroid carcinomas (FTCs) and one Hurthle cell adenoma (HCA)] with 3p25 aneusomy detected by fluorescence in situ hybridization (FISH). 3p25 trisomy was observed in one FTC and one HCA while 3p25 tetrasomy was observed in one FTC. Furthermore, all three lesions did not show overexpression of PPARγ protein. Hurthle cell neoplasms (HCN) are distinct clinically and histologically from other follicular thyroid neoplasms (FTN). However, the presence of the aneusomy in HCA and FTC indicates that there could be a biological continuum between the two and chromosomal gains might play an important role in the pathogenesis of these two types of neoplasms. Despite their differences, HCN and FTN may share the same early genetic event in tumour development.