Immune Checkpoint Inhibitor-Associated Myocarditis Mimicking Takotsubo Cardiomyopathy.

BACKGROUND

Pembrolizumab-induced myocarditis is a rare but life-threatening immune-related adverse event.

CASE SUMMARY: A 72-year-old woman with stage IV EGFR exon 19 deletion-positive left lung adenocarcinoma received osimertinib as first-line therapy. After disease progression, she underwent pembrolizumab plus pemetrexed-carboplatin as second-line therapy, then docetaxel plus ramucirumab as third-line therapy. She presented with nausea and anorexia, and electrocardiograms revealed widespread ST-segment elevation. Coronary angiography revealed no significant stenosis; left ventriculography revealed an apical ballooning pattern. Although Takotsubo cardiomyopathy was suspected, endomyocardial biopsy confirmed pembrolizumab-induced myocarditis. High-dose corticosteroids improved her cardiac function; however, the underlying malignancy progressed.

DISCUSSION: Immune checkpoint inhibitor-associated myocarditis can mimic atypical Takotsubo cardiomyopathy, with persistent changes on electrocardiograms or elevated biomarkers, warranting endomyocardial biopsy for diagnosis and treatment with steroids.

TAKE-HOME MESSAGE: In patients receiving immune checkpoint inhibitors, consider myocarditis in atypical Takotsubo presentations; biopsy and early steroids improve outcomes.