Postoperative retroperitoneal desmoid tumor mimics recurrent gastrointestinal stromal tumor:A case report

Desmoid tumor is a locally invasive,myofibroblastic,nonmetastatic tumor.Its pathogenesis remains unclear and it may involve genetic abnormalities,sex hormones and traumatic injury,including surgery.Postoperative intra-abdominal desmoid tumor is rare,especially in the retroperitoneum.We report a case of postoperative retroperitoneal desmoid tumor that developed 29 mo after the first excision of a gastrointestinal stromal tumor.Sporadic trauma-related intraabdominal desmoid tumors reported in the English literature are also reviewed.Despite an extremely low incidence,postoperative desmoid tumor should be considered in the differential diagnosis when a recurrent neoplasm is found at least one year after operation.However,it is a clinical challenge to distinguish recurrent malignant neoplasms from desmoid tumors,and surgical resection is the treatment option depending on the anatomic location.