Objective: To investigate the histopathological features of pathologic parathyroid specimens associated with negative preoperative technetium Tc 99m sestamibi scans.
Design: Retrospective study.
Setting: Tertiary care center.
Patients: One hundred fourteen patients who underwent sestamibi scans before surgical exploration for primary hyperparathyroidism between 1996 and 2001.
Interventions: Surgical exploration and removal of parathyroid adenomas.
Main outcome measures: Histopathological characteristics associated with true-positive and false-negative sestamibi scans, including parathyroid specimen weight, size, relative oxyphil and chief cell content, parathyroid hormone staining patterns, cellular architecture, and various immunohistochemical staining patterns.
Results: Twenty-three (24%) of 98 patients with parathyroid adenomas had negative sestamibi scan results. Among 20 age- and sex-matched patients with false-negative results vs 20 patients with true-positive results, tumor size (P = .04) and oxyphil cell content (P = .03) were found to be significantly different.
Conclusion: Parathyroid gland size and oxyphil content are descriptive and predict differences between sestamibi properties of parathyroid adenomas but have no current therapeutic implications for parathyroid surgery.