Massive proteinuria as a main manifestation of primary antiphospholipid syndrome

Renal involvement in antiphospholipid syndrome (APS) is increasingly reported. So far, massive proteinuria as the principal feature of primary APS (PAPS) has not been well documented. We describe 3 patients with PAPS and massive proteinuria. Renal biopsy was performed in all 3, and features consistent with membranous and focal segmental glomerulopathy were disclosed. These histological lesions were not yet reported in PAPS. We conclude that the spectrum of renal lesions in PAPS is diverse and that it should be considered in the differential diagnosis of patients with massive proteinuria.