Clinical Course of a Patient With Kidney Failure Due to Isolated Bilateral Renal Extramedullary Plasmacytomas

Plasmacytomas are rare immunoproliferative monoclonal plasma cell diseases of lymphoid lineage that may present in an isolated or systemic manner. Systemic involvement is much more common than occurrences isolated to a particular organ, and for this reason, it is imperative to rule out systemic involvement for osseous and nonosseous isolated neoplasms. These neoplasms present unique challenges due to their location, extent of involvement, vague presentation, and dearth of treatment protocol. We report the case of a 69-year-old man who developed chronic kidney disease stage 4 between 2009 and 2012. Precipitous kidney failure, anorexia, fatigue, and flank pain necessitated clinical follow-up that ultimately led to thorough imaging and bilateral kidney biopsy. Protein electrophoresis, immunohistochemistry, and immunofluorescence were all consistent with bilateral renal extramedullary plasmacytomas. Treatment recommendations are often limited to prior case successes; however, chemotherapy, radiation, and surgery are the mainstay of treatment. Although surgery or combined therapy provides the best results for patients, such options are unfeasible with bilateral kidney involvement. Therefore, a chemotherapy regimen, similar to that for multiple myeloma, was determined to be most reasonable. Treatment consisted of 4 cycles of a bortezomib, cyclophosphamide, and dexamethasone regimen. Three months following chemotherapy, kidney function returned to baseline levels.