Regression of sporadic intra-abdominal desmoid tumour following administration of non-steroidal anti-inflammatory drug

BACKGROUND: Desmoid tumours or fibromatoses are rare entities characterized by the benign proliferation of fibroblasts, which can be life-threatening due to their locally aggressive properties. Surgery is widely accepted as the first line of treatment for extra-abdominal desmoids; however, it is not recommended for intra-abdominal desmoids because of the high-risk of recurrence and difficulties with the operation. Here, we report on a patient with sporadic intra-abdominal desmoid tumours, who showed partial response following the intake of non-steroidal anti-inflammatory drugs. CASE PRESENTATION: A 73-year-old man presented with swelling and pain of the right leg. Computed tomography showed an abnormal multilocular soft-tissue mass (95 × 70 mm) in the right pelvis, which was revealed by biopsy to be a desmoid tumour. Immunohistochemical analysis showed that the tumour cells expressed vimentin, but not smooth-muscle actin, CD34, or desmin. Very few Ki-67-positive cells were found. Non-cytotoxic treatment with etodolac (200 mg/day) was chosen because of the patient's age, lack of bowel obstruction, and the likelihood of prostate cancer. Two years after the commencement of non-steroidal anti-inflammatory drug administration, computed tomography showed a decrease in tumour size (63 × 49 mm), and the disappearance of intratumoural septa. CONCLUSION: Our case report suggests that non-steroidal anti-inflammatory drug treatment should be taken into consideration for use as first-line treatment in patients with sporadic intra-abdominal desmoid tumours.