Background <p>Pulmonary toxicity induced by carfilzomib, while uncommon, represents a serious and potentially life threatening complication.</p> Case presentation <p>We report the case of a 57-year-old man with high-risk multiple myeloma who developed severe acute lung injury following his first dose of carfilzomib. Acute hypoxemia and pulmonary interstitial edema evident on CT emerged shortly after infusion. An extensive diagnostic workup excluded infectious etiologies. His symptoms resolved rapidly with corticosteroid and supportive therapy. Notably, carfilzomib was later successfully re-administered using a modified dosing schedule without recurrence of pulmonary toxicity.</p> Conclusion <p>This case underscores a rare but critical adverse event, illustrating that with vigilant monitoring and prompt intervention, safe treatment continuation is possible—a vital consideration for patients with limited therapeutic alternatives.</p>