[Primary tumors of the diaphragm.  Apropos of a case]. 
The diagnosis of diaphragmatic tumours is complicated by their rarity and because they are often difficult to distinguish from the more frequent tumours of surrounding structures.  We describe two cases: an invasive fibroma and a primary hydatid cyst.  We discuss the differential diagnosis of diaphragmatic tumours and suggest a systematic approach to their radiological diagnosis, stressing the value of ultrasonography, CT scanning and diagnostic pneumoperitoneum.