[Intravascular malignant B-cell lymphomatosis with renal glomerular involvement: a case].

We report a case of intravascular malignant lymphomatosis observed in a 71 year-old male and characterised by the presence of a proteinuria in relation to the specific intraglomerular localisation. This malignant lymphoma, usually of the B phenotype, is rare and affects predominantly the central nervous system and the skin. Neoplastic cells home selectively to endothelium. Histological renal infiltration is frequent but a glomerular localisation, with proteinuria, is rare. The mechanism whereby lymphocytes home to endothelium cells is unclear but it could be related to the expression of lymphocyte-endothelium adhesion molecules. When present the nephrotic syndrome is associated with minimal change disease.