Paraneoplastic fibrillary glomerulonephritis associated with intrahepatic cholangiocarcinoma: When diagnosis of a rare kidney disease leads to successful hepatic cancer treatment.

A 50-year-old man presented with nephrotic syndrome. Electron microscopy analysis of a kidney biopsy specimen showed fibrillary glomerulonephritis, a rare glomerular disease, while histological analysis of a liver tumor biopsy confirmed an intrahepatic cholangiocarcinoma. The paraneoplastic nature of fibrillary glomerulonephritis is debated but after curative treatment of the hepatic nodule, remission of nephrotic syndrome was confirmed at 6-, 12- and 24-months follow-up. To our knowledge, this is the first description of a paraneoplastic fibrillary glomerulonephritis associated with a cholangiocarcinoma, supported by complete remission achieved following cancer treatment.