title: Thyroid diseases cause mismatch between MIBI scan and neck ultrasound in the diagnosis of hyperfunctioning parathyroids: usefulness of FNA-PTH assay.
abstract: METHODS
  To evaluate the efficacy of the main tools in the diagnostic localization of hyperfunctioning parathyroids (HP) in primary hyperparathyroidism (pHPT) with concomitant thyroid diseases.
  
  
  METHODS
  Forty-three patients with pHPT associated with nodular goiter (NG, n=32) and/or autoimmune thyroid diseases (AITDs, n=11) for a total of 63 neck lesions were considered. Sixteen patients displaying HP (16 lesions), unequivocally localized by sestaMIBI scintigraphy (MIBI) and neck ultrasound (US) (group I), were compared with 27 patients (47 neck lesions) displaying equivocal parathyroid localization (group II). In all cases, neck US, MIBI scan, cytology, and parathyroid hormone assay in fine-needle aspiration washout fluid (FNA-PTH) were performed. All patients finally underwent surgery.
  
  
  RESULTS
  According to histological examination, high FNA-PTH values (>103 pg/ml) correctly identified all HP in both groups of patients (100% of sensitivity and specificity). Both MIBI and US correctly identified all HP only in group I patients; in contrast, four patterns of mismatch between these techniques were observed in group II patients, leading to low diagnostic performances of neck US (71.4% sensitivity and 78.9% specificity) and of MIBI scan (35.7% sensitivity and 42.1% specificity). The latter was due to both false-negative (mainly in AITD) and false-positive (mainly in NG) scan images.
  
  
  CONCLUSIONS
  Coexistent thyroid diseases are responsible for mismatch between MIBI and US images resulting in equivocal HP localization. In these cases, FNA-PTH resulted in the most accurate tool to identify HP. However, although safe, it should be advised only to patients with uncertain HP localization.
authors.affiliation: Department of Medical Sciences, University of Cagliari, Monserrato-Cagliari, Italy. francesco.boi@tin.it
authors.forename: Francesco
authors.initials: F
authors.lastname: Boi
authors.forename: Cira
authors.initials: C
authors.lastname: Lombardo
authors.forename: Maria Chiara
authors.initials: MC
authors.lastname: Cocco
authors.forename: Mario
authors.initials: M
authors.lastname: Piga
authors.forename: Alessandra
authors.initials: A
authors.lastname: Serra
authors.forename: Maria Letizia
authors.initials: ML
authors.lastname: Lai
authors.forename: Pietro Giorgio
authors.initials: PG
authors.lastname: Calò
authors.forename: Angelo
authors.initials: A
authors.lastname: Nicolosi
authors.forename: Stefano
authors.initials: S
authors.lastname: Mariotti
mesh_terms: D000328:Adult; D000368:Aged; D044963:Biopsy, Fine-Needle; D005188:False Negative Reactions; D005189:False Positive Reactions; D005260:Female; D006801:Humans; D049950:Hyperparathyroidism, Primary / Q000150:complications* / Q000000981:diagnostic imaging; D008297:Male; D008875:Middle Aged; D009333:Neck / Q000000981:diagnostic imaging*; D010280:Parathyroid Glands / Q000000981:diagnostic imaging; D010281:Parathyroid Hormone / Q000097:blood*; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals; D012680:Sensitivity and Specificity; D017256:Technetium Tc 99m Sestamibi; D013959:Thyroid Diseases / Q000150:complications* / Q000000981:diagnostic imaging; D013961:Thyroid Gland / Q000000981:diagnostic imaging; D014463:Ultrasonography
chemical_list: D010281:Parathyroid Hormone; D019275:Radiopharmaceuticals; D017256:Technetium Tc 99m Sestamibi