[Non-secreting, extra-adrenal retroperitoneal paragangliomas].

OBJECTIVE: Two cases of extra-adrenal non-secretory retroperitoneal paraganglioma in male patients are presented. The first case had intermittent vascular claudication in lower limbs and the second one was an incidental finding during staging of a lymphoma.
METHODS: Both cases were studied using imaging techniques (US, CT and MRI) and histological and immunohistochemical analyses.
RESULTS: The imaging techniques demonstrated solid homogeneous retroperitoneal masses intimately adhered to the abdominal aorta in the first case and located in the left upper hemiabdomen (in front of the left kidney) in the second one. Histological analysis showed a proliferation of spindle cells with cuboid cytoplasm arranged in solid nests, with typical immunohistochemical findings of paraganglioma.
CONCLUSIONS: Extra-adrenal retroperitoneal paraganglioma are rare tumors, particularly the non-secretory variant. The only reliable criteria for malignancy are extensive capsular invasion and distant metastases.