Combined Ganglioneuroma-Schwannoma of the Retroperitoneum: An Exceedingly Rare Hybrid Nerve Sheath-Ganglioneural Tumor.

Combined ganglioneuroma-schwannoma is an exceedingly rare tumor that has only been described in isolated case reports. We document a 64-year-old man with an incidentally discovered combined ganglioneuroma-schwannoma of the retroperitoneum that was intimately associated with sympathetic ganglia. We highlight the morphological and immunohistochemical findings of this rare tumor, and show evidence of its origin from sympathetic ganglia.