Imatinib-associated fluid retention with persistent NT-proBNP elevation during treatment of gastrointestinal stromal tumor: a case report

Background : Imatinib is an established first-line treatment for unresectable or metastatic gastrointestinal stromal tumors and is generally regarded as having an acceptable cardiovascular safety profile. Fluid retention, however, is a well-recognized adverse effect, and uncommon cardiovascular complications have also been described during treatment. Results : A 49-year-old woman with gastrointestinal stromal tumor of the small intestine started imatinib at a dose of 800 mg/day after histological and immunohistochemical confirmation of the diagnosis. Two months after treatment initiation, she developed dyspnea, facial and lower-limb edema, and elevated arterial blood pressure. Echocardiography showed preserved left ventricular ejection fraction and preserved global longitudinal strain. A small, hemodynamically insignificant pericardial effusion adjacent to the right atrium was detected during follow-up after initiation of imatinib therapy. NT-proBNP levels became elevated during follow-up and fluctuated over time, whereas troponin values remained low. After treatment with torasemide and candesartan, the patient reported clinical improvement, and the pericardial effusion resolved, although NT-proBNP levels continued to fluctuate over time. Conclusion : The case points to a possible imatinib-associated presentation in which fluid retention, elevated arterial blood pressure, NT-proBNP elevation with subsequent fluctuations, and a small pericardial effusion occurred despite preserved systolic function. It also underlines the value of early cardiological assessment, echocardiographic follow-up with strain imaging, and cardiac biomarkers in patients who develop cardiovascular symptoms during imatinib therapy.