Peliosis hepatis and hepatic sinusoidal dilatations are rare vascular liver diseases that occur at increased frequency in kidney transplant recipients. We retrospectively evaluated in kidney transplant recipients the natural history of vascular liver diseases, their impact on patient and graft survival, and the influence of AZA withdrawal. Between 1970 and 1990, vascular liver disease was diagnosed in 32 cadaver kidney transplant recipients 1-128 months after transplantation (mean 41 months). Diagnosis was based on histology in all cases. Patients received conventional immunosuppression (high dose steroids and AZA). Twenty patients had a minor form (sinusoidal dilatations or focal peliosis), while 12 had a major form (diffuse peliosis) of vascular hepatic disease. Two patients were lost to follow-up and 1 died at the time of diagnosis. In 12 patients (group 1), AZA dosage remained unchanged, while it was interrupted at the time of diagnosis in 17 patients (group 2). Five group 1 patients underwent serial liver biopsies, which showed persistence of vascular hepatic disease in 3 (with regenerative nodular hyperplasia in 1) and disappearance in 2 patients. Eight group 2 patients underwent serial liver biopsies, which showed disappearance of vascular hepatic disease in 6 patients and persistence in 2. Moreover, regenerative nodular hyperplasia was noted in 1 case, perisinusoidal fibrosis in 1 case, and cirrhosis in 6 cases. Three patients of group 1 and 11 patients of group 2 returned to dialysis a mean of 21 and 39 months after diagnosis, respectively. Eight patients died and death was clearly associated with major peliosis in 2 cases. In kidney transplant recipients, vascular hepatic disease may be associated with high mortality, especially in major forms. Our findings indicate that peliosis hepatis may lead to severe fibrosing liver lesions. The course of vascular hepatic disease is not clearly modified by AZA withdrawal.