Hirokawa M, Suzuki A, Higuchi M, et al. - Through collecting clinical data from the medical records of Kuma Hospital, researchers clarified the histological alterations following fine‐needle aspiration for parathyroid adenoma and discussed the occurrence of diagnostic problems. Among the 392 patients with parathyroid adenoma who had a resection, fine‐needle aspiration was conducted for 21 (5.1%) parathyroid adenoma nodules. The authors showed the prevalence of six histological findings: thick fibrous capsule, multilayered fibrous capsules, capsular pseudo‐invasion, fibrous bands, hemosiderin deposition, and tumor implantation. Such findings are easily confused with those of an atypical adenoma or parathyroid carcinoma. In patients undergoing preoperative FNA, they suggest that histological alterations following fine‐needle aspiration for parathyroid adenoma be removed from pathological findings suggesting atypical adenoma or parathyroid carcinoma. Furthermore, they believe that FNA should not be used in the preoperative diagnosis of PA.