[Extra-uterine twin pregnancy. Observation of a case of bilateral tubal pregnancy and literature review].

Literature was reviewed for the rare case of extra-uterine twin pregnancy, with particular reference being made to a real case of bilateral tubal twin pregnancy. Topographic aspects and age of pregnancy should be taken into account for definition. Aetiological factors and clinical peculiarities are discussed. The author holds that so far less than 100 cases have been reported in which bilateral tubal twin pregnancy had been safely established.