Primary retroperitoneal teratomas: a review of the literature.

Teratomas are uncommon neoplasms comprised of mixed dermal elements derived from the three germ cell layers. Historically, teratomas were attributed to demons, sexual misconduct, and abnormal fertilization. They attract attention because of their bizarre histology and gross appearance. While the majority of teratomas present congenitally in the sacrococcygeal region, within the ovaries of adolescent females and within the testes of young men, they have been identified throughout the body. Extragonadal teratomas tend to occur in midline structures as the anterior mediastinum, retroperitoneum, sacrococcygeal region, and pineal gland. Retroperitoneal teratomas represent only 1-11% of primary retroperitoneal tumors. Incidence is bimodal with peaks in the first 6 months of life and in early adulthood. Due to their location, they are usually identified only after they have grown to huge proportions. There is a 25% chance of malignancy. Surgical resection remains the mainstay of therapy and is required for definitive diagnosis. This article reviews the literature on the histopathology, classification, genetic abnormalities, and theories of origin of teratomas as well as the presentation, diagnosis, and management of retroperitoneal teratomas. Copyright 2004 Wiley-Liss, Inc.