An Uncommon Finding of Plasma Cell Invasion of the Kidney in a Patient with Plasma Cell Dyscrasia: Should It be Considered a Myeloma Defining Event?

Plasma cell invasion of the kidney in plasma cell dyscrasia is rare. We are reporting a case of plasma cell infiltration in the kidney presenting as rapidly progressing renal failure. The patient presented with generalized weakness, anemia, and advanced renal failure. The kidney biopsy revealed multifocal atypical CD138-positive plasma cell-rich interstitial inflammation and severe acute tubular injury. In the present situation of clinically unexplained renal failure with suspicion of plasma cell dyscrasia, a kidney biopsy proved to be key to the diagnosis. Hence, malignant plasma cell infiltration in the kidney could indicate underlying plasma cell dyscrasia and may serve as a future myeloma defining event (MDE).