[Small cell lung cancer revealed by extramembranous glomerulonephritis].

We describe a case of small-cell lung cancer limited to the thorax but with malignant pleural effusion in a 47-year-old man that was revealed by a nephrotic syndrome due to membranous glomerulonephritis (MGN). Chemotherapy led to a partial tumor response with total resolution of the nephrotic syndrome. Tumor relapse did not provoke proteinuria. Primary lung cancer is the cause of about 3% of all cases of MGN and 40% of tumor-related MGN. There are 49 cases of tumor-related MGN in the literature, including 9 cases of small-cell lung cancer.