Diagnose This (August 26, 2019)

What is your diagnosis?

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The image shows a glomerulus on PAS stain with global endocapillary hypercellularity and numerous intracapillary hyaline pseudothrombi. This pattern of injury is most commonly seen in the setting of cryoglobulinemic glomerulonephritis or in lupus nephritis when subendothelial deposits become large enough to protrude into the intracapillary space. In this case the patient had underlying cryoglobulinemia and the immunofluorescence panel showed IgG, IgM, C3, kappa and lambda which are compatible with a mixed (type II) cryoglobulinemia. While the patient did not have lupus or hepatitis C (a common etiology of mixed cryoglobulinemia), they are being worked up for Sjögren syndrome, which is also known to be an etiology of cryoglobulinemia.