Small cell anaplastic carcinoma of the lung with mesangial proliferative glomerulonephritis.

Mesangial proliferative glomerulonephritis is an uncommon manifestation of renal injury associated with neoplastic disease. A 50-year-old woman with small cell anaplastic cancer of the lung and nephrotic syndrome had renal biopsy findings that were consistent with diffuse mesangial cell proliferation. Electron microscopic evaluation of renal tissue demonstrated numerous intramesangial and paramesangial dense deposits. Resolution of the nephrotic syndrome with improvement in renal function was noted after a response of the patient's tumor to combination chemotherapy.