Research Article: Preoperative localization in primary hyperparathyroidism: a stepwise approach integrating PTH-FNA washout and second-line 18 F-choline PET/CT
Abstract:
Accurate preoperative localization of parathyroid adenomas is essential for the success of minimally invasive parathyroidectomy. This study evaluated the detection rate of parathyroid hormone assay on fine-needle aspiration washout and in conventional and advanced imaging modalities modeling a hypothetical stepwise diagnostic approach for primary hyperparathyroidism.
We conducted a retrospective single-center study including 32 patients with primary hyperparathyroidism who underwent minimally invasive parathyroidectomy and preoperative parathyroid hormone assay on fine-needle aspiration washout. We used the PTH-FNA washout to serum PTH ratio as the cutoff: a value greater than 1 was considered indicative of positive localization, while a value equal to or less than 1 was considered negative. Preoperative localization procedures included ultrasonography, MIBI-Scan, and 18 F-choline PET/CT. Results were compared with postoperative histology and biochemical outcome.
Parathyroid hormone assay on fine-needle aspiration washout was positive in 20 of 32 patients (62.5%, 95% CI 45.3–77.1%). Among washout-positive patients, 7 of 20 (35.0%) underwent surgery based on ultrasonography and washout findings alone, with histological confirmation of parathyroid adenoma in all cases. In the washout-positive subgroup in whom MIBI-Scan was also performed, scintigraphy was diagnostic in 7 of 13 cases (53.8%). In washout-negative patients, scintigraphy localized the lesion in 6 of 12 cases (50.0%). In patients with non-localizing washout and scintigraphy findings, 18 F-choline PET/CT identified the lesion in all evaluated cases. In this retrospective series, a stepwise strategy based on ultrasonography combined with needle-aspiration washout as the first-line localization, followed by 18 F-choline PET/CT in washout-negative cases, could have potentially avoided MIBI-scans in 25 out of 32 patients (78.1%; 95% CI 61.2–89.0%).
This retrospective, single-center, post-hoc reconstructed cohort study might suggest a stepwise approach for preoperative localization of parathyroid adenoma based on parathyroid hormone assay on fine-needle aspiration washout combined with ultrasonography as a useful first-line diagnostic technique and reserving 18 F-choline PET/CT for non-localizing cases. It may reduce the use of additional imaging and radiation exposure. Larger prospective studies are needed to confirm these findings.
Introduction:
Primary hyperparathyroidism (PHPT) is an endocrine disorder caused by solitary or multiple hyperfunctioning parathyroid lesions (hyperplasia, adenomas, or, rarely, carcinomas). It has an estimated prevalence of 176 cases in women and 77 cases in men per 100,000 people per year (1995-2010) ( 1 ). In Western Europe, as in the United States, the incidence of unspecified hyperparathyroidism increased steadily to 40.3 per 100,000 woman?years and 13.7 per 100,000 man?years ( 2 ). PHPT has many clinical implications,…
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