Pheochromocytoma and paraganglioma with negative results for urinary metanephrines show higher risks for metastatic diseases.

PURPOSE: Few studies have assessed the clinical features of pheochromocytoma and paraganglioma (PPGL) not producing excessive catecholamine. We aimed to clarify the clinical characteristics of PPGL patients with negative results for urinary metanephrines.

METHODS

This is a retrospective cross-sectional study. We established a database by combining datasets from the Nationwide Cohort Study on the Development of Diagnosis and Treatment of Pheochromocytoma in Japan (PHEO-J) and the Advancing Care and Pathogenesis of Intractable Adrenal diseases in Japan (ACPA-J). We compared the clinical differences between PPGL patients with negative results for urinary metanephrines and those with catecholamine-producing PPGL.

RESULTS

Five hundred PPGL patients in the combined database were analyzed. Among them, 31 were negative for metanephrines. PPGL with negative results for urinary metanephrines was significantly associated with extra-adrenal disease (Odds ratio (OR) 6.58, 95% CI (confidence interval) 3.03-14.3, p < 0.001), the presence of metastatic disease (OR 4.22, 95% CI 1.58-11.3, p = 0.004), and negativity on meta-iodobenzylguanidine (MIBG) scintigraphy (OR 0.15, 95% CI 0.03-0.77, p = 0.023).

CONCLUSIONS

Our findings demonstrate that PPGL patients with negative results for urinary metanephrines are associated with extra-adrenal lesions, metastatic disease, and negative MIBG findings. This suggests that PPGL patients with negative results for urinary metanephrines have a greater need for systemic whole-body imaging other than MIBG scintigraphy and close follow-up to monitor for metastasis than do patients with PPGL overtly producing excessive catecholamine.