RESUMO
Composite tumors containing pheochromocytoma and ganglioneuroma are rare tumors typically arising in the adrenal glands. Very few were reported outside of the adrenals. We present the case of a middle-aged woman with a retroperitoneal mass that was discovered when she complained of local signs of compression and systemic signs of catecholamine hypersecretion. On pathology the mass was composed of large polygonal and pleomorphic cells arranged in nests characteristic of pheochromocytoma that were mixed with clusters of mature ganglion cells and bundles of spindle cells characteristic of ganglioneuroma. The histological features were benign, but due to its invasion of the inferior vena cava and of the right renal artery, we had concerns about the malignant potential of the pheochromocytoma component, which is extremely rare in these composite tumors