[Proboscis lateralis, a rare facial malformation. Therapeutic difficulties (apropos of a case)].

A case of proboscis lateralis with total absence of the corresponding half of the nose is reported. The length of the mucocutaneous cylinder enabled initial insertion of its free extremity around its bony orifice in communication with the single nasal fossa, and the creation of a functional, well situated naris. Second-stage operation several months later involved spreading of the upper part, closure of the coloboma, and treatment of the lacrimal pathways. Total liberation of the superior pedicle and final modelling is to be envisaged at a later date as a function of growth.