Presentation of one case of retroperitoneal ganglioneuroma in a 31-year old female. This type of neoformation, with origin at the sympathetic system nodes level, is considered to be the benign homologous of neuroblastoma. Peak incidence age ranges from 3 to 20 years. The retroperineum is one of the most frequent sites, second only to the mediastinum. Diagnosis is normally casual and is considered definite when, following mass removal and completion of the pathoanatomical study, the presence of neuroblasts in the tumour can be ruled out.