Pheochromocytoma and paraganglioma: An emerging cause of secondary osteoporosis

Context: Pheochromocytoma (PHEO) and paraganglioma (PGL) (PHEO and PGL: PPGLs) are catecholamine-producing neuroendocrine tumors, which are known to be associated with low bone mineral density (BMD). However, it remains unknown whether PPGLs are associated with high prevalence of osteoporotic fracture and if so, whether their surgical resection improves BMD has been addressed.

Objective: To evaluate the risk of vertebral fracture (VF) in PPGLs and the improvement of BMD after surgery.

Design and settings: A retrospective cross-sectional study in a single referral center.

Participants: This study included the following patients: 1) 49 patients with PPGLs and 61 patients with non-functional AT who were examined radiograph of the spine, 2) 23 patients with PPGLs who were examined BMD at follow-up.

Intervention: 1) The prevalence of VF was evaluated between PPGLs and non-functional AT. 2) In PPGLs, BMD was evaluated at baseline and after surgery.

Results: PPGLs had a higher prevalence of VF (43% [21/49]) than non-functional AT (16% [10/61]; p = 0.002). PPGLs were associated with VF after adjusting for age and sex (odds ratio, 4.47; 95% confidence interval, 1.76-11.3; p = 0.001). In PPGLs, BMD at the lumber spine was improved (before: 0.855 ± 0.198 g/cm², after: 0.888 ± 0.169 g/cm², mean of the difference: 0.032 g/cm², p = 0.026), with 3.8% increase.

Conclusion: This study demonstrates that PPGLs was associated with VF and that their surgical resection contributes to the improvement of BMD in the trabecular bone. These observations support the notion that PPGLs are an emerging cause of secondary osteoporosis.