Renal involvement in Behçet's syndrome.

A retrospective study of 77 cases of Behçet's syndrome showed that, of the 33 patients in whom urinalysis was done (including three with systemic amyloidosis reported earlier), 17 had pathological results. A prospective study of 51 of these patients uncovered eight additional subjects with urinary abnormalities, bringing the total to 25. The urinary abnormality was, as a rule, discrete, consisting of proteinuria and/or microhematuria. These occurred in some patients persistently, in some intermittently, in some alternatingly, and in some simultaneously. The initial finding was proteinuria in 10 patients, hematuria in 11, and both in 4. Over the years, eight showed only hematuria, seven only proteinuria and ten, both. The urinary sediment contained neither leukocytes nor casts. Pyelographies were unrevealing when performed and rectal biopsies uncovered no new instance of amyloidosis. These data suggest that a benign renal lesion occurs in Behçet's syndrome, whose pathological substrate, though not yet defined, is not amyloid deposition.