The authors report three cases of a palpable abdominal mass without clinical evidence of obstruction. In each case, ultrasound diagnosed a solid tumor. Computer tomography examination measured the density of the tumor and the extension of the disease. In each case, the colonic origin was established owing to surgery. Histological examination of the three cases diagnosed a fibroma of the caecum, an enterogenic cyst of the caecum and a T-lymphosarcoma developed from the wall of the left colon.