Key result
Cardiac undifferentiated pleomorphic sarcoma can follow an indolent course and mimic benign myxomas on imaging.
Why the study?
Cardiac undifferentiated pleomorphic sarcoma is rare, highly malignant, and presents diagnostic challenges because of nonspecific symptoms, early diagnosis difficulties, and potential to mimic benign tumors.
Cardiac undifferentiated pleomorphic sarcoma can present with an unusually indolent course and mimic benign tumors like myxoma on imaging, requiring a high index of suspicion.
Requires high suspicion for malignancy in presumed myxomas; extends known spectrum of cardiac undifferentiated pleomorphic sarcoma.
Cardiac undifferentiated pleomorphic sarcoma (UPS) is a rare and highly malignant tumor, commonly arising in the left atrium. It is associated with poor prognosis, nonspecific symptoms, and difficulty in early diagnosis. Here, we report a case of a 71-year-old woman who presented with palpitations, chest pressure, and exertional dyspnea, in whom initial cardiac magnetic resonance imaging revealed only subtle atrial septal thickening, evaluated as nonspecific, whereas follow-up imaging 2 years later showed progressive growth, ultimately interpreted as a cardiac myxoma. Surgical resection was performed, and histopathologic examination revealed a high-grade UPS with immunohistochemistry and molecular profiling supporting the diagnosis, including amplification of MDM2 and PDGFRA. No metastases were detected, and after multidisciplinary discussion a decision was made to abstain from adjuvant therapy. This case highlights the diagnostic challenge posed by cardiac UPS mimicking benign tumors such as myxoma on imaging and the importance of longitudinal imaging review and a high index of suspicion in cases with atypical radiological features of myxoma. It also raises awareness of an unusually indolent behavior of an UPS that otherwise pursues an aggressive course.
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Ziaei et al. (2026) studied this question. Cardiac undifferentiated pleomorphic sarcoma can exhibit an unusually indolent course over several years and mimic benign myxomas on imaging, posing significant diagnostic challenges.
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