Clinical History: A 42 year-old male patient referred to rule out intestinal obstruction; history of appendectomy and laparotomy.
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Figure 1
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Figure 2
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Figure 3
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Figure 4
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Figure 5
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Figure 6
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Figure 7
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Figure 8
CT Findings: There are surgical staples in the right hypochondriac region indicating previous resection side. There is obvious retroperitoneal predominately low density mass of about 12 cm x 8 cm with multiple cystic areas with the thick peripheral rim with anterior displacement of the second part of the duodenum and mesenteric vessels with distended stomach with persistence of oral contrast in gastric lumen even in delayed series suggestive of partial outlet obstruction Proximal small gut loops are distended and there is obvious narrowed segment in the distal small gut with associated bowel wall thickening in right lower quadrant, suggestive of distal intestinal obstruction.
Diagnosis: Paraganglioma
Paragangliomas are rare tumors that arise from extra adrenal chromaffincells. During embryogenesis, neural crest cells migrate to diverse locations in the body and differentiate into chief and sustentacular cells, which are designated as paraganglia.
Extra luminal perigastric masses are frequently considered to be gastrointestinal stromal tumors (GISTs) or other soft tissue sarcomas, when histological confirmation is not possible. Paragangliomas may have a similar radiographic appearance. In the absence of histological diagnosis and symptoms of catecholamine excess, paragangliomas may be mistaken for GISTs. Perigastric abdominal mass presumed to be a GIST after nondiagnostic biopsy, is presented.
On abdominal CT, there are no unique imaging characteristics specific for paragangliomas. Consequently, these tumors may be mistaken for other primary epithelial or mesenchymal abdominal tumors. For instance, GIST, the most common sarcoma of the gastrointestinal tract, may have a similar radiographic appearance. They are often large (84 percent N 5 cm) tumors arising from the stomach with heterogeneous enhancement (84 percent) and central necrosis (37 percent). Retroperitoneal paragangliomas affect mainly adults in the fourth or fifth decade of life, with no sex predilection.
While size and location help to differentiate GISTs from paragangliomas, correlation with clinical symptoms is needed. A presumed GIST considered to be resectable does not necessarily warrant preoperative biopsy, and thus further diagnostic workup is not pursued.
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