[Histopathology of bilharziasis].

Our conception of Bilharziosis, one of the oldest known illness, has been considerably modified during the last twenty years with the development of Immunology. In fact, it is now established that the severity of the illness depends upon the importance of granuloma which arises round the emprisoned egg in the tissues and the sclerosis mutilation which follows. It is possible to describe, successively around the egg, exsudative granuloma, productive granuloma, and sclerocicatricial nodule whose size will depend upon the tissular immunity. In particular this granuloma will be practically non-existent when the endogenic desensitization of the subject is maximal. In this case the egg will remain undestroyed and there will be egg's calcification in the tissue. Contrarily, in the case of minor tissular immunity there will be serious collagenous mutilations as in Symmers hepatic fibrosis. It is therefore preferable that a histopathological study be part of the routine investigations of this disease: it confirms itself as one of the best prognostic criteria.