Mesangiolysis in the glomerular lesion of cyanotic congenital heart disease

Mesangiolysis associated with glomerulomegaly was observed in an autopsy case of an 11-year-old boy with cyanotic congenital heart disease, i.e. complete transposition of the great vessels with large VSD. Microscopical examination of the kidney revealed marked enlargement of glomeruli with mesangiolysis mainly found in the midzonal cortex involving 16 to 20% of all glomeruli. The glomerular basement membrane in the mesangiolytic lesion showed splitting, between which red blood cells were occasionally encountered. By reconstruction study with serial sectioning, the mesangiolysis was observed to be obviously focal and segmental. Immunofluorescent study revealed no positive results for IgG, IgA, IgM, C3, and fibrinogen/fibrin. By electron microscopic study on the post formalin fixed specimens, no remarkable dense deposits were found in any structural components of the glomeruli. It was assumed that the mesangiolysis might have been provoked by some circulatory disturbances, which superimposed on the preexisting glomerular lesion of cyanotic congenital heart disease in the terminal stage of the clinical course.