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Archive: June 2018

Light Chain Deposition Disease

The immunofluorescence in cases of monoclonal immunoglobulin deposition disease is characterized by linear tubular basement membrane staining. In these cases, the positive staining is restricted to the monoclonal immunoglobulin leading to disease. The photomicrographs here show strong staining for kappa compared to lambda in a case of kappa light chain deposition disease. There is also commonly staining of the interstitium, vessels, and glomeruli. When the monoclonal immunoglobulin is a heavy chain, the immunofluorescence shows strong staining for the depositing heavy chain with little to no staining for either light chain.

The “C” in CKD

This renal biopsy illustrates severe chronic kidney injury and its effects on all major compartments of the cortex: most glomeruli are globally sclerotic, the atrophic tubules are widely spaced, the interstitium is fibrotic, and the arterial walls show intimal fibrosis. Interestingly, such morphologic changes can either result from acute renal injury followed by weeks to months of ongoing damage or an insidious, decades-long kidney disease without an identifiable acute event. The degree of chronic injury should help inform the selection and aggressiveness of therapy and provide an objective measure of the likelihood of functional recovery.  

Diagnose This (June 25, 2018)

What immunofluorescence stain is shown here, what is the immune complex deposition pattern and what disease does it represent?   ​   ​ ​   ​   ​ ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​ ​   ​...

Pushing Glass (June 22, 2018)

The patient is an 80 year-old male who presents with fatigue and a creatinine of 6.5 mg/dl. He was in his normal state of health until he and his grandchild went to the park on a hot afternoon. Subsequently, he began to feel ill and fatigued and went to see his physician. He has a past medical history significant for long-standing hypertension which is treated with a loop diuretic. Based on this history and images, what is the best diagnosis? A. Waldenstrom macroglobulinemia B. Light Chain Deposition Disease secondary to lymphoplasmacytic lymphoma C. Light Chain Deposition Disease secondary to small...

Twitter Poll (June 20, 2018)

ANSWER: D While the majority of cryoglobulinemic GN’s do not show ultrastructural organization in deposits by EM, classically described deposits are subendothelial/intramembranous and composed of organized microtubular structures (10-30 nm wide). They can show “fingerprinting” patterns and can also be seen within intraluminal thrombi in glomerular capillaries.

Proliferative Glomerulonephritis with Monoclonal IgG Deposits

This renal biopsy from a 57-year-old male with acute renal failure, hematuria, and nephrotic-range proteinuria shows a proliferative glomerulonephritis (A) with IgG kappa-restricted deposits by immunofluorescence. These findings are consistent with the entity known as proliferative glomerulonephritis with monoclonal IgG deposits (PGNMID). Approximately 30% of patients with these renal biopsy findings prove to have an associated monoclonal immunoglobulin in the serum. However, the underlying etiology in the majority of these cases is undetermined as most do not have evidence of infection, autoimmune disease or hematologic malignancy.

Immunotactoid Glomerulopathy

Immunotactoid glomerulopathy is one of many glomerular diseases characterized by organized deposits.  Figure 1 shows characteristic glomerular changes seen with Masson trichrome staining, including capillary wall thickening, capillary proliferation, mesangial matrix expansion, glomerular tuft lobulation, and fuchsinophilic capillary wall deposits.  Immunofluorescence findings may include IgG deposits and light chain restriction (kappa more often than lambda).  Figure 2 shows the microtubule deposits seen by electron microscopy.  These tubular type deposits characteristically show hollow centers with at least some degree of parallel arrangement.  Of note, there is a strong association between immunotactoid glomerulopathy and underlying lymphoproliferative disease. The differential diagnosis of immunotactoid...

Digging Deeper, Literally

This biopsy came from a 79-year-old patient. He had presented with acute renal failure. His serum creatinine was up to 2.0 mg/dL, from a normal baseline. He also had proteinuria, which was quantified as approximately 1 g. His serum albumin was low at 2.5 g/dL. The patient was anemic, and hemoglobin was 9.1. The patient had been investigated with an extensive serologic work up. ANA was negative, C3 was within normal limits, and SPEP was negative for monoclonal proteins. However, ANCA serologies were positive. Based on that, the patient had been treated with high doses of steroids for a few...

Focal Segmental Glomerulosclerosis (FSGS), Tip Variant

This biopsy was performed on a 9-year-old female with no significant past medical history, who presents with nephrotic syndrome. The serum creatinine at the time of the biopsy was 0.7 mg/dl. The UPCR was 9.6 g/g. Serum albumin was 2.1 g/dl. Complement levels and ANA were normal/negative. The biopsy shows glomeruli with minimal mesangial matrix expansion and hypercellularity (Fig 1), in the absence of segmental glomerulosclerosis or proliferative lesions. Immunofluorescence was negative for IgA, IgG, IgM, C3, C1q and kappa and lambda light chains (not shown). Electron microscopy shows widespread blunting, widening and effacement of epithelial foot processes (Fig 2),...