Two cases of proteasome inhibitors related thrombotic microangiopathies and literature review

BACKGROUND: Multiple myeloma (MM) is a prevalent hematological malignancy, with proteasome inhibitors (PIs) playing a crucial role in its therapeutic management. Although PIs are generally well-tolerated and associated with relatively mild side effects, recent evidence has increasingly drawn attention to proteasome inhibitor-related thrombotic microangiopathy (PI-related TMA). CASE PRESENTATION: Here, we report two cases with high clinical suspicion for PI-related TMA, highlighting the diagnostic process and subsequent management strategies. Clinical suspicion of PI-related TMA prompted the discontinuation of the offending agent and consideration of plasma exchange therapy, which proved beneficial in selected patients. These case reports further facilitate a detailed discussion regarding the underlying pathogenic mechanisms and potential therapeutic approaches for PI-related TMA in MM. CONCLUSION: PI-related TMA is a rare but life-threatening complication in MM. Early recognition and prompt discontinuation of the offending drug are critical. Plasma exchange and eculizumab may be considered in selected cases.