Intra‐abdominal desmoid tumor after laparoscopic low anterior resection for rectal cancer: A case report

: Desmoid tumors are monoclonal fibroblastic proliferations arising from soft tissue classified as intra-abdominal, extra-abdominal and abdominal wall types. We present a patient with an intra-abdominal desmoid tumor diagnosed 20 months after laparoscopic resection of rectal cancer. A 70-year-old woman with hematochezia was diagnosed with advanced rectal cancer. Preoperative chemoradiotherapy followed by laparoscopic low anterior resection was performed. During follow-up, a nodular soft-tissue density measuring 28 mm was detected in the presacral region. Metastasis from rectal cancer was diagnosed and four courses of chemotherapy were given, including capecitabine, oxaliplatin and bevacizumab. Computed tomography scan showed that the mass slightly decreased in size and surgical resection was performed. Histopathological examination revealed a proliferation of spindle-shaped cells and collagenous stroma diagnosed as a desmoid tumor. This report highlights the possibility of a desmoid tumor in the differential diagnosis of an intra-abdominal mass found during follow-up after resection of colorectal cancer including following laparoscopic resection.