Extrarenal teratoma with nephroblastoma in the retroperitoneum

RATIONALE Teratoma with nephroblastoma is a rare disease. The most common site at which teratoma with nephroblastoma occurs is the kidney. The mechanisms underlying the development of teratoma with nephroblastoma have not been fully elucidated. PATIENT CONCERNS In the current report, we describe the clinical characteristics of a 3-year-old girl with a complaint of a painless abdominal mass in the upper right side of the body. Ultrasonography and computed tomography revealed a cystic-solid mass with a clear boundary. DIAGNOSIS Surgical resection and a subsequent pathological examination confirmed that the mass contained teratoma tissues and renal blastemal components, which supports the diagnosis of teratoma with nephroblastoma. INTERVENTIONS The patient underwent an exploratory laparotomy through a transverse abdominal incision. Complete resection of the mass was performed in this patient. OUTCOMES The patient's postoperative course was uneventful and she was discharged on the 8th postoperative day. The girl had no complaints during the 2 years follow-up period. LESSONS Teratoma with nephroblastoma is a rare entity that typically presents in childhood. Due to its rarity, no standardized criteria have been established for the categorization and treatment of these lesions. However, a complete excision of this tumor allows the diagnosis to be confirmed and lowers the risk of recurrence.