Combined crystal-storing histiocytosis, light chain proximal tubulopathy, and light chain crystalline podocytopathy in a patient with multiple myeloma: a case report and literature review

Abstract

Background Crystal-storing histiocytosis (CSH), light chain proximal tubulopathy (LCPT), and light chain crystalline podocytopathy (LCCP) are rare complications of multiple myeloma (MM) or monoclonal gammopathy of renal significance, and their diagnoses are challenging. Case presentation In this case, a 69-year-old Chinese woman presented with suspicious Fanconi syndrome with renal insufficiency. Immunofixation electrophoresis of both serum and urine revealed elevated immunoglobulin G kappa (IgGkappa) and kappa light chain. Bone marrow aspirate revealed 15% plasma cells with considerable cytoplasmic granular inclusions and needle-shaped crystals. Renal biopsy confirmed the final pathologic diagnosis of kappa-restricted CSH, combined LCPT and LCCP by immunoelectron microscopy. A number of special casts were present which could easily be misdiagnosed as light chain cast nephropathy. Immunofluorescence on frozen tissue presented false negative for kappa light chain, as ultimately proven by paraffin-embedded tissue after pronase digestion. MM and CSH were diagnosed, and two cycles of chemotherapy were given. The patient subsequently refused further chemotherapy, and her renal function remained relatively stable during a 2.5-year follow-up period. Conclusions In conclusion, we report a rare case of generalized kappa-restricted CSH involving bone marrow and kidney, combined with LCPT and LCCP, provide a comprehensive summary of renal CSH, and propose a new nomenclature of monoclonal immunoglobulin-induced crystalline nephrology. The presentation of monoclonal immunoglobulin and Fanconi syndrome should suggest the presence of monoclonal immunoglobulin-induced crystalline nephrology. Use of paraffin-embedded tissue after pronase digestion and immunoelectron microscopy is beneficial to improve the sensitivity of diagnosis.

Tubular basement membrane amyloid deposition: is it an indicator of renal progression in light chain amyloidosis?

“…No other symptoms were suggestive of Fanconi syndrome. This is typically observed in light chain proximal tubulopathy when the excess free light chain injures proximal tubular epithelial cells, sometimes with crystal formation in the cytoplasm [ 15 ]. Very rarely, intracellular amyloid, termed amyloid proximal tubulopathy, has been detected in such cases [ 16 ].…”

Multiple myeloma-associated light chain proximal tubulopathy: a case report

“…The deposition of monoclonal immunoglobulins (MIg) in the proximal tubules could lead to multiple myeloma (MM),which could cause to a broad spectrum of progressive kidney disorder.Up to 40% of the patients with MM will develop kidney impairment and 10 to 15% of them require dialysis 1 .According to the US Renal Data System, nearly 1.2% of the patients with end-stage renal disease (ESRD) are associated with MM 2 .Among MIg deposition diseases, light chain proximal tubulopathy (LCPT) which mainly caused by Blymphocyte tumor, such as MM,is particularly uncommon 3,4 . Only 28 cases of crystal-storing histiocytosis with renal involvement have been reported in the literature,some of which presented with LCPT 4 . LCPT is classified as crystalline or noncrystalline according to the cytoplasmic inclusions in the proximal tubules 5 The accurate histopathologic diagnosisis is critical for treatment of LCPT 2 .…”