To the Editor.—
Luft et al in their report (234:1158, 1975) relate the finding of renal vein thrombosis to the massively obese state of the patient described. Although they discount primary renal disease antedating the vascular complications, it seems more plausible to invoke a mechanism not considered by them in detail. The authors describe "basement membrane thickening" and "membranous glomerular changes," but illustrate this with a hematoxylin- and eosinstained photomicrograph. Detailed observations with other stains, eg, periodic acid-methenamine silver (Jones), Masson trichrome, periodic acid-Schiff, are not reported, so that it is not possible to determine if, indeed, the alterations of the glomerular capillary wall are due to the presence of immunoglobulin deposits and the accompanying basement reaction ("spikes"), typical of membranous nephropathy, the result of considerable basement thickening, or another process.Many factors permit more than idle speculation that an underlying membranous nephropathy would explain this patient's course. (1) This