Detection and diagnosis of parathyroid incidentalomas during thyroid sonography

Andrea Frasoldati, Marialaura Pesenti, Elena Toschi, Clorinda Azzarito, Michele Zini, Roberto Valcavi

Research output: Contribution to journalArticlepeer-review


Purpose. The aim of our study was to evaluate the incidence of incidentally found parathyroid adenomas (incidentalomas) in patients undergoing sonography of the neck for thyroid disease. Methods. A total of 1,686 patients (305 men and 1,381 women) underwent sonography of the neck; the mean age was 49.6 ± 21.7 years. In 38 patients (2.3%; 7 men and 31 women) with a mean age of 48.7 ± 14.7 years, hypoechoic, homogeneous, oval nodules (mean volume, 1.0 ± 0.9 cm3) adjacent to the thyroid parenchyma were observed. All these lesions, compatible with the shape of an enlarged parathyroid gland, underwent ultrasound-guided fine-needle aspiration biopsy (FNAB), with measurement of parathyroid hormone (PTH) and thyroglobulin (Tg) levels in the needle washings (FNAB-PTH and FNAB-Tg). Biochemical screening for hyperparathyroidism was also performed. Results. Cytologic examination plus FNAB-PTH/FNAB-Tg measurements revealed the presence of cellular material consistent with parathyroid tissue in 9 patients (24%), thyroid tissue in 22 patients (58%), and lymphoid tissue in 4 patients (11%). A tissue diagnosis was not established in 3 patients (8%). Five of 9 patients with parathyroid enlargement had high serum PTH and calcium levels. Conclusions. Enlarged parathyroid glands may be incidentally discovered during sonography of the thyroid. In patients with thyroid disease, the positive-predictive value of sonography in the identification of parathyroid tissue was low. Ultrasound- guided FNABPTH determination should be carried out when parathyroid adenoma is suspected. The incidental finding of an enlarged parathyroid may or may not be associated with yet undiagnosed hyperparathyroidism.

Original languageEnglish
Pages (from-to)492-498
Number of pages7
JournalJournal of Clinical Ultrasound
Issue number9
Publication statusPublished - Nov 1999


  • Hyperparathyroidism
  • Incidentaloma
  • Parathyroid
  • Parathyroid adenoma
  • Ultrasonography

ASJC Scopus subject areas

  • Radiology Nuclear Medicine and imaging
  • Radiological and Ultrasound Technology
  • Acoustics and Ultrasonics


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