Use of surgeon-performed office ultrasound and parathyroid fine needle aspiration for complex parathyroid localization

Background. This study investigates the utility of ultrasound guided parathyroid fine needle aspiration (FNA) as a localizing technique in patients with hyperparathyroidism (HPT) undergoing re-operative neck surgery or with unusually appearing or ectopically located glands. Methods. Selected patients with HPT underwent surgeon-performed FNA with ultrasound guidance. Aspirate contents were sent for cytology and parathyroid hormone (PTH) levels. All patients subsequently underwent parathyroid exploration. Results. 54 patients underwent 57 ultrasound guided parathyroid biopsies. Indications for FNA included prior parathyroid (n = 29), thyroid (n = 11), or other neck surgery (n = 2), or unusual parathyroid appearance or location (n = 12). A true positive was defined as a site where the PTH aspirate was >40 pg/mL and a hypercellular gland was removed at surgery. Based on this, there were 44 true positives, 10 true negatives, and 3 false negatives; there were no false positives. The median PTH level in positive aspirates was 11,665 pg/mL. Cytology was primarily helpful in excluding other diagnoses. Conclusion. Ultrasound guided FNA is a highly specific localization test for parathyroid tumors. This procedure can be successfully performed by surgeons in the office setting and is extremely valuable for directing parathyroid exploration in challenging cases. We recommend incorporating ultrasound and FNA as a pre-operative localization strategy for selected patients with HPT.