Bone mineral density in a cohort of patients with phaeochromocytoma and paraganglioma (#324)
Introduction: Neural control of bone is mediated through the sympathetic nervous system, with sympathetic activation causing bone loss from increased bone turnover. Consistent with this, beta-blocked patients have reduced fracture risk1. A recent case-control study demonstrated increased markers of bone resorption in patients with phaeochromocytoma with normalization following adrenalectomy2. This suggests phaeochromocytoma may cause low bone mineral density (BMD) through increased bone turnover, and potentially increase risk of fracture. We assessed BMD in patients with a current or previous catecholamine-secreting tumour.
Methods: The study cohort consisted of patients with biochemical and subsequent histopathologically diagnosis of phaeochromocytoma or paraganglioma between January 2002 and March 2013. Participants completed a questionnaire and dual-energy x-ray absorptiometry (GE Lunar) was performed to assess areal BMD (aBMD) at lumbar spine and both total hips.
Results: To date, eighteen patients have been assessed. Mean BMD Z-scores were 0.100 at right hip, 0.165 at left hip and -0.047 at the lumbar spine, with no significant reduction in BMD expected for age and gender in this cohort compared with the general population. These results were similar when adjusted for duration of phaeochromocytoma remission. Previous fractures were self-reported by 10 patients in this cohort (23 total fractures), with most occurring prior to resection of their catecholamine-secreting lesion; however, none were fragility fractures.
Discussion: In this cohort of patients with current or previous phaeochromocytoma BMD was not significantly different to that expected for age and gender. A high number of fractures was reported in this cohort. The majority of these occurred prior to the diagnosis of phaeochromocytoma and raise the possibility of an alteration in bone homeostasis that normalizes after adrenalectomy. The findings suggest further investigation is warranted and that measurement of BMD should be considered in patients with a catecholamine-secreting tumour at the time of diagnosis.
- Yang et al. 2012. Association between beta-blockers and fracture risk: a Bayesian meta-analysis. Bone. 51(5):969-74
- Veldhuis-Vlug et al. 2012. Bone resorption is increased in phaeochromocytoma patients and normalizes following adrenalectomy. JCEM. 97(11):E1-E5