title: The small abnormal parathyroid gland is increasingly common and heralds operative complexity.
abstract: BACKGROUND
  Over decades, improvements in presymptomatic screening and awareness of surgical benefits have changed the presentation and management of primary hyperparathyroidism (PHPT). Unrecognized multiglandular disease (MGD) remains a major cause of operative failure. We hypothesized that during parathyroid surgery the initial finding of a mildly enlarged gland is now frequent and predicts both MGD and failure.
  
  
  METHODS
  A prospective database was queried to examine the outcomes of initial exploration for sporadic PHPT using intraoperative PTH monitoring (IOPTH) over 15 years. All patients had follow-up ≥6 months (mean = 1.8 years). Cure was defined by normocalcemia at 6 months and microadenoma by resected weight of <200 mg.
  
  
  RESULTS
  Of the 1,150 patients, 98.9 % were cured and 15 % had MGD. The highest preoperative calcium level decreased over time (p < 0.001) and varied directly with adenoma weight (p < 0.001). Over time, single adenoma weight dropped by half (p = 0.002) and microadenoma was increasingly common (p < 0.01). MGD risk varied inversely with weight of first resected abnormal gland. Microadenoma required bilateral exploration more often than macroadenoma (48 vs. 18 %, p < 0.01). When at exploration the first resected gland was <200 mg, the rates of MGD (40 vs. 11 %, p = 0.001), inadequate initial IOPTH drop (67 vs. 79 %, p = 0.002), operative failure (6.6 vs. 0.7 %, p < 0.001), and long-term recurrence (1.6 vs. 0.3 %, p = 0.007) were higher.
  
  
  CONCLUSIONS
  Single parathyroid adenomas are smaller than in the past and require more complex pre- and intraoperative management. During exploration for sporadic PHPT, a first abnormal gland <200 mg should heighten suspicion of MGD and presages a tenfold higher failure rate.
authors: Division of Endocrine Surgery, University of Pittsburgh, 3471 Fifth Avenue, Kaufmann Building, Suite 101, Pittsburgh, PA, 15213, USA, mccoykl@upmc.edu.
authors: Kelly L
authors: KL
authors: McCoy
authors: Naomi H
authors: NH
authors: Chen
authors: Michaele J
authors: MJ
authors: Armstrong
authors: Gina M
authors: GM
authors: Howell
authors: Michael T
authors: MT
authors: Stang
authors: Linwah
authors: L
authors: Yip
authors: Sally E
authors: SE
authors: Carty
mesh_terms: D000236:Adenoma / Q000150:complications / Q000473:pathology* / Q000601:surgery*; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D015331:Cohort Studies; D016208:Databases, Factual; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D049950:Hyperparathyroidism, Primary / Q000209:etiology / Q000601:surgery; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative / Q000379:methods*; D009361:Neoplasm Invasiveness / Q000473:pathology; D009364:Neoplasm Recurrence, Local / Q000175:diagnosis / Q000601:surgery; D009367:Neoplasm Staging; D010281:Parathyroid Hormone / Q000097:blood; D010282:Parathyroid Neoplasms / Q000150:complications / Q000473:pathology* / Q000601:surgery*; D016105:Parathyroidectomy / Q000379:methods*; D011446:Prospective Studies; D018570:Risk Assessment; D013997:Time Factors; D016896:Treatment Outcome; D047368:Tumor Burden; D055815:Young Adult
chemical_list: D010281:Parathyroid Hormone