Rapid Wash out from Parathyroid Adenomas/Hyperplastic Glands: Comparison of Primary Versus Secondary Hyperparathyroidism

Presentation Number: MON 349
Date of Presentation: April 3rd, 2017

Yevgeniya Kushchayeva*1, Shiksha Sharma2, Sergiy Kushchayev3, Douglas Van Nostrand4 and Kanchan Kulkarni2
1NIDDK, National Institutes of Health, Bethesda, MD, 2MedStar Washington Hospital Center, Washington, DC, 3Mercy Catholic Medical Center, Darby, PA, 4Medstar Health Research Institute, Washington, DC

Abstract

Introduction. 99mTc-Sestamibi (SeS) is a standard tool for localization of adenomas/hyperplasia (PA/Hs) in hyperparathyroidism (HPTH) designed on the difference between thyroid and parathyroid tissue radiotracer washout on early and late phases of scintigraphy (Caveny S et al, 2012). Classic pattern of SeS retention by PA/Hs and washout from thyroid on late phase occurs in 60-75% (Lorberboym et al, 2003; Caveny et al, 2012). In some cases PA/Hs can be missed due to radiotracer rapid washout (RW). There is limited literature on relationship of different forms of HPTH on SeS RW. The aim of this study was to characterize RW in primary (pHPTH) and secondary HPTH (sHPTH) and utility of parathyroid imaging in these cases.

Materials and methods. Patients with HPTH after parathyroidectomy (2012 -2013) with available dual phase SeS parathyroid imaging, pathology report, pre- and postsurgical biochemical HPTH workup have been included. Correlative imaging with 123I performed on selective patients was also used for analysis. 76 patients with 119 PA/Hs of age 58.3+12.5yr and M:F ratio 1:3.2 were analyzed. 75% (57/76) had pHPTH and 22.4% (17/76) were diagnosed with sHPTH. One tertiary HPTH and one parathyroid carcinoma case were excluded from further analysis.

Results: Single PA/H was found in 69.7% and multiglandular disease in 30.3% of patients. sHPTH patients had significantly higher multiglandular involvement (4/57 vs 17/17) and postoperative PTH levels (34.4+32 vs 183+143pg/ml) with no difference in postoperative calcium (Ca) levels.

Among all glands, 67.2% (80/119) were positive on early SeS phase, and 48.74% (58/119) retained radioisotope on late SeS phase.

1. RW was identified in 18.5% of all PA/Hs (22/119).

2. Size: PAs positive on late SeS scans were significantly large being 2+0.9 vs 1.65+0.77cm (p<0.05). No size difference was noted between positive vs negative PA/Hs on early SeS phase (1.77+0.9 vs 1.83+0.83cm).

3. There was no significant difference in preoperative levels of PTH and Ca on retention of SeS radiotracer in late phase in both pHPTH and sHPTH.

4. PA/Hs in sHPTH vs pHPTH were significantly more often negative on both early and late SeS scans (43.9 vs 22.6%, p <0.05) and less often demonstrated RW (10.5 vs 25.8%, p<0.05) PA/Hs in pHPTH had higher SeS detection rate on early phase SeS scans (77.4 vs 56%, p<0.05).

5. There was no significant difference in number of PA/Hs positive on both early and late imaging (51.6 vs 45.6%) between pHPTH and sHPTH.

123I scintigraphy, as an additional diagnostic tool, was positive in 83.3% of PA/Hs with RW but was not effective in all cases that were negative on both early and late SeS scintigraphy.

Conclusion: Based on our results, RW occurred in 18.5% of surgically confirmed PA/Hs and depends on PTs size and type of HPTH being more common in pHPTH but neither on preoperative PTH nor Ca levels.

 

Nothing to Disclose: YK, SS, SK, DV, KK