[Remote course of bony cysts in children and adolescents]

The author, who in 1955 had published a thesis on the remote results of the treatment of bone cysts on children and teenagers, decided to go back to that subject 30 years later. He was able to gather 203 observations (mostly from Paris Hospitals) followed up for at least 2 years (some of them for more than 30 years) and in 15 of those cases no treatment had been undergone. The pathogenesis of the bone cyst is still unknown, but there are obvious connections between the cystic socket and the vascular metaphysis. Rigault and Padovani had the opportunity to observe, during some injections of contrasting preparation in the humeral cysts that the liquid went quickly into the auxiliary venous system. The bone cysts appear in the spongy tissue of bone metaphysis in full movement. The author thinks that the cystic sockets are made by the gathering of osteolytic bubbles and that the protrusions inside the bone are nothing, but the former limits of those bubbles. The evolution does not always follow the classical pattern and one can often observe--in particular in the humeral localisation--lytic outbreaks on a cyst which growth seemed stationary or on the way of recovery. Those outbreaks with specific evolution bring about either an extension of the socket or the appearance of a new geode. The recovery (total or partial) usually comes after septation of the cavity. It is only at the end of the growth that one can be sure of the stabilization of the remaining lesions. As for the spontaneous disappearance of the cavity, it can take years. Considering the ever encouraging evolution of the bone cysts, one must always be very careful in judging the efficacy of the different treatments that are recommended. The different traumatisms (fractures, surgery or corticoids) bring forth perturbations in the bone socket, according to a pattern that we do not know well. The result is often paradoxical: one bone cyst which was apparently stabilized will awake and spread; another, partially cured after a surgery will have to wait for a fracture of the remaining cavity to disappear completely; other bone cysts which the injections of corticoids have failed to cure will recover after a curettage or vice-versa. Every method, included the bone resections used in some localisations (fibula) can fail.(ABSTRACT TRUNCATED AT 400 WORDS)