Two cases of pneumatocele are reported. As our cases suggest and as the literature reports, the pneumatoceles are almost always benign lesions, whose resolution is only partially influenced by the therapy. On contrary their worrying radiological aspect and their long persistence can induce erroneously to think not efficacious the started therapy and therefore to change it. The etiology and the pathogenesis of pneumatocele are not completely clarified, even if various theory have been proposed.