American Association of Endocrine Surgeons- Annual Meeting Abstract Papers

USE OF SURGEON-PERFORMED OFFICE ULTRASOUND AND PARATHYROID FINE NEEDLE ASPIRATION (FNA) FOR COMPLEX PARATHYROID LOCALIZATION
A. Stephen, M. Milas, C. Garner, K. Wagner & A. Siperstein
Cleveland Clinic Foundation, Cleveland, Ohio

Background: The key to successful re-operative parathyroid surgery is accurate preoperative tumor localization. This study investigates the utility of ultrasound (U/S)-guided parathyroid 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 U/S guidance during their office evaluation. Aspirate contents were sent for cytology and an aliquot diluted in 5 mL of saline for parathyroid hormone (PTH) levels. All patients subsequently underwent parathyroid exploration.
Results: From 2000-present, 908 patients underwent parathyroidectomy; of these, 54 patients (6%) underwent 57 U/S-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). All biopsies were well tolerated and performed without complications. 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 (range 44 -13,000,000). In negative aspirates the median PTH level was 9 pg/mL (range < 4 - 23). Cytology was primarily helpful in excluding other diagnoses. All re-operative patients with positive biopsies underwent successful explorations.
Conclusions: U/S 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. Use of parathyroid aspiration early in the evaluation process achieves prompt diagnosis and determines which additional imaging studies, if any, are necessary. Based on these data, we recommend incorporating U/S and FNA as a pre-operative localization strategy for patients with re-operative, ectopic, or unusual cases of HPT.