THIS SYMPOSIUM on retroperitoneal tumors concerns itself with the clinical aspects of diagnosis and treatment. The classification to be presented has been designed as an aid to the clinician who is called upon to make an identification of a questionable tumor. The term tumor will be used in the broad sense of any morbid enlargement or swelling, and, while pathologic types are included, no attempt is made to include all the many histopathologic types of tumors which have been reported in the literature.
For the clinician, retroperitoneal tumors must include all tumors occurring in the retroperitoneal space. This space is bounded by the diaphragm above and the brim of the true pelvis below, and it lies between the posterior peritoneum in front and the muscles of the abdominal wall behind. Many cases of these tumors are first brought to the physician's attention because of a palpable mass in the abdomen.