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Archive: September 2017

Thrombotic Microangiopathy

This biopsy is from a person in their 40’s, who presented with accelerated hypertension and blood pressure of 240/180 mm/Hg. Urinalysis showed 2+ protein and 2+ blood and his serum creatinine was 7.2 mg/dl. Further workup revealed a low platelet count at 90,000 and schistocytes on peripheral smear. He was admitted to the ICU where careful hypertension management was instituted. Serologies were negative for ANA, cANCA, pANCA, anti-GBM, and hepatitis B and C. Complements were normal. ADAMTS-13 was normal. Diagnosis: Thrombotic Microangiopathy Global Glomerulosclerosis (20/72). Interstitial Fibrosis, Severe. Arteriosclerosis and Arteriolar Hyalinosis, Severe. Discussion: Thrombotic microangiopathy is a pattern that...

Arkanines: Beau

Meet Beau! He is still a puppy and a bundle of energy. Beau can’t get enough of tug of war and is always racing around. He hops like a rabbit, loves to fetch, but doesn’t like to actually the return the toy. He always seems to be smiling and has never met a toy or person he doesn’t like. Beau belongs to Dr. Steve and Chris Bonsib.

Monoclonal Membranous Glomerulopathy

Membranous glomerulopathy (MG) is a common cause of nephrotic syndrome that results from the formation of immune complexes along the subepithelial aspect of the glomerular basement membranes. Approximately 1% of membranous cases will show light chain restriction by immunofluorescence. The majority of MG cases with light chain restricted deposits lack a recognizable secondary etiology. However, absence of PLA2R-positivity within glomerular deposits, positive staining for a single IgG subclass and presence of focal proliferation by light microscopy are worrisome histopathologic features that should prompt a thorough clinical workup to exclude the presence of an underlying lymphoproliferative disorder, even in the absence...

Bile Cast Nephropathy

Bile cast nephropathy is one cause of acute or chronic kidney injury in patients with liver disease (especially obstructive cholestasis). Figure 1 shows two paraffin blocks containing kidney biopsies from two different patients. The upper block shows the typical appearance of a paraffin-embedded core biopsy of kidney tissue. The tissue in the lower block (indicated by the arrow) shows prominent green discoloration and was taken from a patient with hyperbilirubinemia due to underlying liver disease. Figure 2 shows the corresponding light microscopic findings, which include acute tubular injury associated with numerous green-brown casts. Histochemical staining confirmed the presence of bile...

Birthday Kidney

Each team here has their own way of celebrating birthdays. The Marketing team has the “Birthday Kidney.” He gets to sit at your desk on your special day. Side note: Our transcription team celebrates birthdays the best. They’re known for their amazing potlucks.

Subepithelial Deposits in Lupus Nephritis

According to the ISN/RPS 2003 classification of lupus nephritis, membranous lupus nephritis (class V) is characterized by the presence of global or segmental subepithelial immune deposits with or without associated mesangial deposits or mesangial hypercellularity. Membranous lupus nephritis may occur in isolation or may coexist with other forms of active lupus nephritis such as focal (class III) or diffuse (class IV) lupus nephritis. In the presence of active glomerular lesions, scattered subepithelial deposits are common and are not diagnostic of membranous lupus nephritis (class V). In fact, in order to make a diagnosis of membranous lupus nephritis (class V) in...

Diagnose This! (September 25, 2017)

What is your diagnosis?     ​   ​ ​   ​   ​ ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​ ​   ​ ​   ​ ​   ​ ​     ​   ​   ​...

Monoclonal Gammopathy of Renal Significance

The renal biopsy shown here has an MPGN pattern of injury by light microscopy. Routine immunofluorescence on the fresh (unfixed) tissue is negative for immune reactants but repeat staining on the formalin fixed paraffin embedded tissue after protease retrieval shows positive staining for IgG and kappa. A subsequent bone marrow biopsy revealed a small clonal B-cell population. A recent case series (see reference below) detailed a cohort of patients with renal biopsy findings similar to those shown here, namely an MPGN pattern by LM and false negative staining for immunoglobulins by routine IF that are ‘unmasked monoclonal deposits’ by performing IF...

Chronic Transplant Arteriopathy

This image shows an arterial cross-section with features of chronic transplant arteriopathy (a.k.a. “sclerosing transplant vasculopathy” and “chronic allograft vasculopathy”). The lesion is characterized by fibrous intimal thickening of the arterial wall with lymphocytes (usually T-cells) and monocytes/macrophages within the thickened intima. Unlike some arteriosclerotic lesions in patients with hypertension, the arterial wall in chronic transplant arteriopathy lacks prominent accumulation of elastic fibers. Given the presence of mononuclear cells in the vessel wall, one must carefully search for endothelialitis. If found, a diagnosis of active vascular rejection, antibody-mediated rejection or acute T-cell-mediated rejection, should be considered.