Case Presentation:
A 70-year-old male with an initial presentation of back pain and difficulty walking was diagnosed with IgD lambda subtype of International Staging System (ISS) stage II MM eight years prior to current presentation with only bony lesions and without renal disease. He was found to have a T3 tumor with lytic bone lesion which was managed by a laminectomy and radiation therapy. He was able to achieve a very good partial response with 6 cycles of lenalidomide, bortezomib, and dexamethasone (RVD). The patient underwent high dose chemotherapy followed by autologous stem cell transplant and was subsequently started on maintenance therapy with 10 mg lenalidomide. He had multiple relapses and underwent multiple lines of therapy. Most recently, the patient was on once weekly salvage therapy with carfilzomib, pomalidomide, and dexamethasone (KPd), however, he developed anemia grade 3 and neutropenia grade 4. He was hospitalized due to acute kidney injury with oliguria likely due to cast nephropathy in the setting of progressive MM. His renal function improved significantly following treatment with cyclophosphamide 1 gm/m2 for 2 days, pulse dexamethasone 40 mg for 5 days, and rasburicase 3 mg due to hyperuricemia and tumor lysis syndrome. During hospital stay, the patient had significant abdominal pain and distension. Paracentesis revealed ascitic fluid with elevated white blood cell count indicating possible SBP. An abdominal ultrasound with liver doppler ruled out any liver pathology and ascitic fluid cultures were negative. The peritoneal fluid cytology demonstrated the presence of numerous atypical CD138+ plasma cells with lambda light chain restriction on kappa/lambda immunoglobulin light chain immunostaining and this confirmed our suspicion of malignant plasmacytic ascites (Figure 1A-D). The patient’s condition progressed rapidly over a period of one month. Thereafter, he was further evaluated for possible non-B cell maturation antigen (BCMA) directed therapies under clinical trials. He was hospitalized multiple times for pleural effusions requiring thoracentesis and pleural catheter placement to alleviate his worsening dyspnea. The possibility of malignant effusion was considered since his respiratory symptoms were new and of sudden onset. Accordingly, a confirmatory pleural fluid cytology and immunohistochemistry was performed which revealed atypical plasma cells positive for CD138 with lambda immunoglobulin light chains restriction (Figure 2A-D). Concurrently, his serum creatinine levels rose dramatically from 0.86 mg/dL to 2.63 mg/dL and evolved to acute renal insufficiency necessitating a cystoscopy to place ureteral stent. Although the patient’s kidney function improved after one cycle of cyclophosphamide, bortezomib, and dexamethasone (CyBorD), he developed an uncontrolled atrial fibrillation. The patient was transitioned to hospice care and ultimately died.