Remission of Primary Hyperparathyroidism After Diagnostic Fine-Needle Aspiration Biopsies of Parathyroid Adenoma

Background: The parathyroid hormone (PTH) measurements in washouts from the fine-needle aspiration biopsy (FNAB) of parathyroid adenoma could be considered in preoperative diagnostics of primary hyperparathyroidism (PHPT). Aims: Preoperative remission of PHPT following FNAB is presented, with discussion of the possible pathophysiological mechanisms and clinical implications. Case presentation: We describe a case of a female patient with confirmed PHPT and a suspected parathyroid adenoma who underwent FNAB with PTH washout measurement as part of the diagnostics. Following FNAB, the patient experienced normalization of biochemical parameters, accompanied by a reduction in tumor size. This outcome is presumed to be associated with autoinfarction or hemorrhage within the adenoma triggered by the biopsy procedure. Conclusions: This case highlights a rare but clinically significant phenomenon of FNAB-induced remission of PHPT and explains why alternative treatments such as thermal ablation may be considered to avoid surgery.