Nonfunctional, nonchromaffin paragangliomas of the retroperitoneum

Two nonfunctional, nonchromaffin paragangliomas of the retroperitoneum are reported, one of which was histologically malignant and metastasized to lungs, liver, and bones. A compilation of the clinical findings for all reported nonfunctional, nonchromaffin paragangliomas in the retroperitoneum shows that 14 of 21 patients presented with abdominal or back pain and/or a palpable abdominal mass. The tumors were tan‐grey or red, solid, circumscribed or partially encapsulated, and closely related to the aorta. They bled profusely on biopsy or handling. Twelve of 21 patients either had neoplasms that metastasized or had multiple primary neoplasms; only 9 patients had single retroperitoneal tumor masses. Retroperitoneal paragangliomas are more likely to be histologically malignant, to infiltrate and metastasize, and to occur in younger patients than are similar neoplasms in other locations.