Malignant fistulae of the gastrointestinal tract.

Internal malignant fistulae of the gastrointestinal tract involving two or more loops of different segments of the bowel are rare. The colon is frequently one of the participating loops. Observations on four such cases indicate that the fistulous tract connecting the two bowel loops is usually linear, somewhat wide, and does not produce significant approximation of the bowel loops involved. These radiographic features help to differentiate such fistulae from the benign type.