Spontaneous regression of a sporadic intra-abdominal located desmoid-type fibromatosis

BACKGROUND: Desmoid-type fibromatosis (DTF) is a rare benign proliferation of myofibroblasts with an unpredictable disease course. Treatment of intra-abdominal located DTF is difficult because of the close relationship with vital organs. CASE PRESENTATION: A healthy young male presents with an asymptomatic palpable mass in the lower right abdominal quadrant. A computed tomography shows a 10 × 7 cm(2) pear-shaped mass, and pathological examination revealed DTF. A watchful waiting approach was initiated, as the patient was asymptomatic and surgery would imply a significant amount of intestinal resection. After a follow-up of 2 years, the tumor has regressed spontaneously and the patient is still without symptoms. CONCLUSIONS: DTF is a difficult to treat condition where individualized management is appropriate. An asymptomatic patient could be treated with a watchful waiting approach, even with intra-abdominal location. Thereby sparing unnecessary morbidity as the tumor can be stable for many years or even regress spontaneously.