Paraganglioma of the mesenterium: a case report.

Extra-adrenal paragangliomas constitute 10 % or less of phaeochromocytomas/paragangliomas. Even rarer is the occurrence of paragangliomas outside the usual distribution of paraganglionic tissue. We report a case of extra-adrenal paraganglioma occurring in the small intestine mesentery in a 65-year-old man. To our knowledge, there are only seven case reports of paraganglioma occurring in this non-typical site. Computed tomography showed a solid expansive non-homogenously enhancing mesenteric mass, measuring 10 x 8 cm with peripheral cystic component. Histologically, the tumour had a typical organoid "zellballen" pattern, showed immunohistochemical positivity for synaptophysin, neuron specific enolase, CD-56, chromogranin, and focally vimentin, and was cytokeratin and EMA negative. S-100 protein stained few sustentacular cells. The patient was free from recurrence or metastasis three months after tumour resection. Although rare, paraganglioma should be included in the preoperative differential diagnosis of solid mesenteric tumours, to prevent any potential life-threatening event peroperatively in the case of a catecholamines-producing tumour.