Do Patients With Atypical Parathyroid Adenoma Need Close Follow-up?

Abstract

Atypical parathyroid adenomas (APAs) are neoplasms with uncertain malignant potential but lack unequivocal histological signs of malignancy. This work aims to retrospectively evaluate the clinical and biochemical profiles of patients with APA, the outcome after parathyroidectomy (PTX), and the presence of CDC73 germline and somatic mutations. This monocentric study was conducted on consecutive patients undergoing PTX for primary hyperparathyroidism (PHPT) between June 2000 and December 2020. Fifty-eight patients with a confirmed histopathological diagnosis of APA, and age- and sex-matched controls with parathyroid adenoma (PA) were also included. Fifty-four patients had sporadic PHPT and 4 had familial isolated hyperparathyroidism (FIHP). Thirty-four patients (59%) had symptomatic disease. Serum calcium and parathyroid hormone (PTH) levels were significantly higher in symptomatic compared to asymptomatic patients (P = .048 and .008, respectively). FIHP patients were younger than their sporadic counterparts (30 ± 17 years vs 55 ± 13 years). APA patients had significantly higher serum calcium and PTH levels and lower 25-hydroxyvitamin D concentration, bone mineral density, and T score at one-third distal radius compared to those with PA. Four of 56 APA patients displayed a CDC73 germline mutation. No somatic CDC73 mutation was identified in 24 tumor specimens. The mean follow-up after surgery was 60 ± 56.4 months. All but 6 patients (90%), 5 with apparently sporadic PHPT and 1 with FIHP, were cured after surgery. The large majority of patients with APA, despite a moderate/severe phenotype, have a good prognosis. Germline CDC73 mutation-positive patients had a higher rate of persistent/recurrent disease. CDC73 gene alterations do not seem to have a relevant role in the tumorigenesis of sporadic APA.