A rare case of Takotsubo cardiomyopathy.

Background: The recent advent of the cyclin-dependent kinase (CDK) 4/6 inhibitors has considerably evolved hormone receptor (HR)-positive/human epidermal growth factor receptor 2 (HER2)-negative metastatic breast cancer treatment. Palbociclib, an orally administered pyridopyrimidine derivative, was the first CDK4/6 inhibitor to be introduced into daily clinical practice in combination with classic endocrine backbone, based on progression-free survival (PFS) benefit assessed in the pivotal PALOMA series of randomized clinical trials. Regarding its safety profile, neutropenia and leukopenia are the most common and well-defined adverse effects, while cardiac complications are rather scarce.

Case Report: We present the rare case of a middle-aged female patient with HR+/HER2- metastatic breast cancer, without prior exposure to cardiotoxic antineoplastic agents, who developed Takotsubo cardiomyopathy (TTC) in the context of systemic therapy with palbociclib plus letrozole combination.

Conclusions: Pharmacovigilance and experimental studies are warranted to confirm any causative relationship and to explore the underlying pathophysiology, respectively.