Intraoperative PTH Measurement Allows Comfirmation of Double Parathyroid Adenoma as a Cause of Primary Hyperparathyroidism
RT Lewis, DL Fraker, VA LiVolsi. University of Pennsylvania Health System, Philadelphia, PA; Hospital of the University of Pennsylvania, Philadelphia, PA
Background: Two synchronous parathyroid adenomas (double adenoma) is a rare cause of primary hyperparathyroidism, with some questioning its existence. Routine intraoperative PTH (IOPTH) measurement as an adjunct to minimally invasive parathyroidectomy now allows identification of cases in which removal of 2 glands results in cure.
Design: A database of medical, clinical, and anatomic pathology information of 1000 consecutive surgeries for hyperparathyroidism performed between 1998 and 2007 was retrospectively reviewed. All cases in which 2 glands were removed were subjected to histologic review by an endocrine pathologist in a blinded fashion. Morphologic, histologic, and cytologic characteristics were recorded. Follow up was performed via phone survey and medical record review.
Results: Twenty seven cases of double adenoma were identified from 845 cases of primary HPT (3.2%). The average age was 59 years old, with 20 women, and 7 men. The most common configuration was bilateral upper gland involvement (13 of 27, 48%). The median weight of the involved glands was 381mg (nl 35-60mg). 31 (61%) were predominantly chief cell type, 6 (12%) oncocytic cell type, 1 (2%) clear cell type, and 13 (25%) mixed. All were hypercellular, 65% had a rim of normocelluar tissue. Oil-Red-O Sudan staining on frozen section showed decreased intracellular lipid in 53%, and completely absent lipid in an additional 28% (19% had normal amounts of intracellular lipid). IOPTH measurement of serum intact PTH was performed in all cases. The IOPTH dropped a median of 39% after the first gland was removed (from 16.3 to 11.4 pmol/ml), and 83% after the second gland was removed (to 2.3 pmol/ml). 11% of cases fell into the normal range (<6.5pmol/ml) after the first gland was removed. Of 18 patients available for long term follow up (median follow up 66 months, range 16-84), 1 patient had persistent hypercalcemia due to incomplete surgery, which was cured by later excision of the second adenoma. There were no recurrences.
Conclusions: Double parathyroid adenoma exists, although less common than previously reported. It usually involves both upper glands. It can be accurately identified with routine IOPTH measurements, and can be cured surgically without fear of recurrence. Pathologic review, including staining for intracellular fat, and comparison to biopsies of normal glands, is important in confirming the diagnosis.
Category: Head & Neck
Wednesday, March 24, 2010 9:30 AM
Poster Session V # 168, Wednesday Morning