Functional extra-adrenal paraganglioma of the retroperitoneum giving thoracolumbar spine metastases after a five-year disease-free follow-up: a rare malignant condition with challenging management.

Paragangliomas are benign neoplasms that arise from the autonomic nervous system and the associated paraganglia. Although benign, they have been shown to possess metastatic potential. Extra-adrenal retroperitoneal paraganglioma with vertebral metastasis is considered very uncommon. Here, we present a case of a functional extra-adrenal paraganglioma of the retroperitoneum giving metastasis to T4 vertebra after five years of follow-up in a 48-year-old man who had been initially treated with complete resection of the primary tumor. The condition of the patient improved significantly after radiosurgery and somatostatin analogs treatment, until lumbar spine lesions appeared six months later. Our case demonstrates that retroperitoneal paraganglioma is a rare condition which should be considered in the differential diagnosis of a retroperitoneal mass combined with vertebral lesions. Additionally, increased physician awareness and long-term follow-up is mandatory for all patients with history of retroperitoneal paraganglioma since metastases may occur after long latent intervals from the initial diagnosis.