Paragangliomas are rare neuroendocrine tu mors that arise in the autonomic nervous system (ANS). Pheochromocytoma is the most common abdominal paraganglioma. Mesenteric paraganglioma are very rare and only 21 cases have reported in the English li terature to date.

A 74-year-old female patient sought medical care due to chronic unspecific abdominal pain in the right hypochondriac and lumbar regions associated with early satiety and postprandial abdominal bloating over the past 6 months. She did not have history of significant medical or surgical conditions. The lab tests were normal. A contrast enhanced computed tomogra phy (CT) scan of the abdomen showed an expansive tu mor with soft tissue density and well-defined borders at the level of the mesentery. The mass measured 74 x 72 x 96 mm in diameter, presented homogenous en hancement and was adjacent to the hepatic segment VI and the third part of the duodenum (Figure 1).

Figure 1 CT scan showing mesenteric tumor (black arrow) and its relation with the pancreas and duodenum (white arrow). 

The patient underwent surgery via a Kocher in cision. A mesenteric tumor was found anteriorly to the duodenum and pancreas with lax adhesions to these organs and close to the liver, gallbladder and hepatic flexure. The tumor was dissected and the vascular pedi cle arising from the second part of the duodenum was ligated. The patient was discharged on postoperative day 2 without complications.

Figure 2 Surgical specimen. 

The pathological examination identified a so lid, encapsulated mass with fibroblasts and blood cells and endothelial cells in nests, surrounded by vessels. Immunohistochemical staining showed positive stai ning for chromogranin, synaptophysin and neurofila ment, suggestive of mesenteric paraganglioma.

Paragangliomas are rare tumors arising from the neuroendocrine cells of the sympathetic or paras ympathetic paraganglia of the ANS.

Although these tumors are considered benign, they can metastasize in a variable percentage of cases (3 to 50%).

Paragangliomas are most found (90%) in the adrenal medulla and may give rise to pheochromo cytomas. Extra-adrenal paragangliomas can appear anywhere in the paraganglia system. In the abdomen, these tumors are often found adjacent to the aorta, between the superior mesenteric artery and aortic bi furcation, particularly the area corresponding to the or gan of Zuckernadl. Mesenteric paraganglioma are very rare, and only 21 cases have been published in PubMed.

The peak incidence occurs in two decades of life, one in the third and the other in the fifth; malig nant transformation is variable (14-50%).

They can be classified and functioning and non-functioning. Functioning paragangliomas cause symptoms secondary to the release of catecholamines (palpitations, sweating, headache), while non-functio ning tumors are usually silent and their symptoms de pend on their size and compression of adjacent organs.

In 50% of the cases paragangliomas are asso ciated with inherited syndromes, as hereditary para ganglioma, NEM2, von Hippel Lindau syndrome, Car ney triad and neurofibromatosis type 1; therefore, it is recommended to perform genetic testing in family members.

The diagnosis is made by imaging tests, parti cularly CT scan, where the tumor appears as a roun ded lesion with regular margins and homogeneous enhancement with the administration of IV contrast agent. Despite being the first imaging test requested, ultrasound is not usually useful for the diagnosis due to the retroperitoneal location of the lesion. Functioning tumors are diagnosed by scintigraphy with 131I meta-iodobenzylguanidine. Positron emission tomography (PET) is useful to evaluate distant metastases.

The differential diagnoses include primary tu mors (desmoid tumor or lipoma), secondary neoplasms (lymphoma, leiomyosarcoma or GIST) and inflam matory or infectious processes (tuberculosis or mesen teric lymphadenitis).

Surgical resection of the tumor with adequate margins in the gold standard treatment. If firm adhe sions or infiltration to adjacent structures are found, particular to the small intestine, en bloc removal of these organs may be necessary. Adjuvant therapy is controversial due to the few benefits demonstrated but can be used in selected cases.

The histological characteristics are not decisive to determine malignancy, which is basically defined by the presence of metastasis. The most common sites of metastasis are the lungs, bones and spleen. Up to date, one two cases of malignant mesenteric paraganglioma with lymphatic invasion have been reported.