title: Unusual manifestation of crystalline light chain tubulopathy in patient with multiple myeloma: case report and review of the literature.
abstract: Multiple myeloma (MM) is the second most common hematological malignancy, with an annual incidence in Europe and the USA of about 4-6 cases per 100,000. Several forms of renal disease are found in the course of MM, including: cast nephropathy, light chain (LC) deposition disease and primary amyloidosis. Less frequent forms include: acute and chronic tubulopathies, neoplastic plasma cell infiltration and interstitial nephritis. In this paper, we discuss a case of 53-year-old male patient with MM who presented with massive proteinuria (24 g/24 h), mild renal insufficiency (eGFR 43 mL/min), and Fanconi-like syndrome (as reflected by normoglycemic glycosuria). In kidney biopsy glomeruli were normal, whereas abundant AFOG-positive deposits were found in the cytoplasm of proximal tubular epithelial cells. These deposits were strongly positive for kappa light chains on immunofluorescence. Electron microscopy revealed electron-dense, intracytoplasmic crystalloid deposits of variable shape (needle-shaped, round and rectangular), and size in the proximal tubular cells. This unusual variant of microscopic renal lesions in the course of MM coupled with coincidence of Fanconi-like and nephrotic syndrome as a clinical manifestation has not been reported to date.
authors: Department of Nephrology, Hypertension and Internal Medicine, University of Warmia and Mazury , Olsztyn , Poland .
authors: Tomasz
authors: T
authors: Stompór
authors: Agnieszka
authors: A
authors: Perkowska-Ptasińska
authors: Małgorzata
authors: M
authors: Wojciechowska
authors: Katarzyna
authors: K
authors: Zając
authors: Agnieszka
authors: A
authors: Chmielewska-Badziąg
authors: Anna
authors: A
authors: Pawłowska
mesh_terms: D005198:Fanconi Syndrome / Q000150:complications* / Q000473:pathology; D006801:Humans; D007668:Kidney / Q000648:ultrastructure; D008297:Male; D008875:Middle Aged; D009101:Multiple Myeloma / Q000150:complications* / Q000175:diagnosis; D011507:Proteinuria / Q000209:etiology* / Q000473:pathology; D051437:Renal Insufficiency / Q000150:complications* / Q000473:pathology
keywords: Chronic kidney disease; crystalline nephropathy; fanconi syndrome; multiple myeloma; nephrotic syndrome