Extra-adrenal Composite Paraganglioma with Ganglioneuroma Component Presenting as a Pancreatic Mass

Paragangliomas may have composite forms in which they combine features of a typical paraganglioma with those of a neural component consisting of either neuroblastoma, ganglioneuroblastoma, or ganglioneuroma. These variants are rare and generally located in the adrenal. Herein, we describe a retroperitoneal, extra-adrenal composite paraganglioma–ganglioneuroma of a 57-year-old woman. Radiological evaluation revealed a nodular mass with apparent pancreatic location, with findings suggestive of an endocrine tumor, yielding the diagnosis of a pancreatic endocrine tumor. At histology the neoplasm, strictly adhering to the external surface of the pancreatic gland but well demarcated, displayed a main central region with typical paraganglioma features and cells arranged in cords and in a nesting “zellballen” pattern, positive for neuroendocrine markers, and a distinct peripheral area consisting of dense bundles of wavy spindled Schwann cells, with scattered ganglionic cells.