[A rare case of sigmoidoduodenal neoplastic fistula (author's transl)].

The clinical case of a patient with sigmoidoduodenal neoplastic fistula is taken as the starting-point for a review of the relevant literature. The great rarity of fistulisation of a sigmoid tumour of the 4th portion of the duodenum is stressed. A clinical definition of the disease is followed by a discussion of the various methods of surgical treatment, with emphasis on the problem presented by reconstruction of the duodenum owing to its anatomosurgical difficulties.