Background: Retroperitoneal teratoma is uncommon germ cell tumor presenting as abdominal mass in children and its incidence in adults is extremely rare. Symptoms of retroperitoneal teratoma are variable but in benign cases there is never an alteration of patient’s general condition.
Case Report: A 35 years old lady presented with history of persistent backache for the last 15 years for which she took analgesics. X-ray of the lumbar spine showed a calcifying shadow in left upper quadrant of the suprarenal area. CT scan confirmed the mass with calcifications and fluid
levels containing predominantly adipose tissue. At surgery a retroperitoneal tumor was found adherent to the left adrenal gland but separate from the kidney. A histopathological diagnosis of primary mature retroperitoneal teratoma without any immature component was made and patient was followed up with serum alpha fetoprotein levels.
Conclusions: Retroperitoneal teratomas are rare and difficult to diagnose because of nonspecific signs and symptoms. Ultrasonography and CT scan are helpful in diagnosis. Surgical excision is curative and recurrence is monitored by serum alpha fetoprotein in malignant cases.

Keywords: retroperitoneum, Teratoma, germ cell