Bone, a double victim in metastatic catecholamine secreting tumors

Benign catecholamine-secreting pheochromocytoma and paraganglioma (PPGL) can cause secondary osteoporosis. Metastatic PPGLs, often presenting with bone metastases, elevated catecholamine levels and persistent disease, may lead to more severe bone impact. We investigated bone density and quality in three cases of metastatic PPGL over long-term follow-up.

Two patients had paragangliomas: a 43-year-old with an SDHB-related abdominal paraganglioma secreting norepinephrine, and a 35-year-old with an aggressive SDHA-related paraganglioma secreting both norepinephrine and dopamine. The third patient, aged 50years, had a sporadic pheochromocytoma producing norepinephrine and dopamine. Bone mineral density (BMD) and quality were studied using dual-energy X-ray absorptiometry (DXA). The 43-year-old and 35-year-old patients exhibited lumbar and hip osteoporosis. The 43-year-old patient also showed changes in the trabecular bone score (TBS) and suffered from both osteoporotic and metastatic vertebral fractures. The 50-year-old patient had a mildly reduced hip T score but no TBS impairment. Additionally, the 35-year-old patient underwent high-resolution peripheral quantitative computed tomography (HR-pQCT), revealing a moderate decline in total BMD in the right tibia and reduced trabecular thickness in the left radius, although there were no vertebral fractures. This patient was treated shortly after diagnosis by bone resorption inhibitors, due to metastatic vertebral fractures.

Impaired bone density and quality, possibly related to long-term exposure to catecholamine excess, contribute to skeletal-related events in metastatic PPGL. Recognizing these complications is important for patient management.