Mucin secreting cancer with mesangial IgA deposits

Subclinical immune complex glomerular deposits occurred in 20% (11 of 55) of cancer cases examined postmortem. Eight of 11 (72.7%) mucin secreting adenocarcinomas of lung, stomach, large intestine and pancreas showed glomerular mesangial deposits of IgA, with associated IgM and C3 in one-half of them. The glomerular morphology showed predominantly minimal or minor changes, and less frequently mesangial cell proliferation. None of the patients exhibited clinical evidence of glomerulonephritis. The nature of the antigen(s) in the paraneoplastic phenomenon was not defined, but there may have been environmental antigen(s) or specific immune response in the local population to explain the IgA deposition.