Overview of primary adult retroperitoneal tumours.

In front of a primary retroperitoneal tumour, it is necessary to have in mind all possible diagnoses in order to specify the diagnostic strategy and the treatment. According to the World Health Organization (WHO) classification of tumours, mesenchymal benign and malignant tumours (including sarcomas and, currently, neurogenic tumours), parasympathetic tumours, extragonadal germ cell tumours, and lymphoid tumours have been identified. By definition, primary retroperitoneal tumours start independently from the retroperitoneal organs. Secondary lesions, carcinoma metastasis, and adenopathy are excluded from this definition, but they can also develop in the retroperitoneal space and lead to misdiagnoses. In the absence of positive tumour markers or an evocative biology, percutaneous biopsy is necessary. Pathological diagnosis is necessary to decide whether surgery must be done, its timing among the other treatments, and its extension. This paper summarizes all the diagnostic possibilities.