Monophasic synovial sarcoma of the left ventricle of the heart: An extremely rare case and literature review

BACKGROUND: Cardiac sarcomas account for <25 of all cardiac tumors. Of these, angiosarcomas are the most frequent. Synovial sarcomas (SS) are exceedingly rare. We present a case of primary left ventricle (LV) SS, a form of sarcoma particularly rare in the heart. CASE DESCRIPTION: A 19-year-old male was referred for further investigation of a LV tumor, presented with a 3-month history of exertional dyspnea and palpitations. He also experienced several syncopal episodes. The radiologic examination confirmed a mass in the LV, suspected for myxoma of the LV. Histopathologic examination revealed a malignant tumor with spindle cell components, suggesting leiomyosarcoma with differential diagnosis of monophasic SS. Immunohistochemistry demonstrated reactivity of the spindle cell component with the mesenchymal marker vimentin and BCL2 protein, while the smooth muscle marker, desmin, was negative, confirming the diagnosis of monophasic SS. CONCLUSIONS: Monophasic SS in the heart is diagnostically challenging since it shares the broad list of differential diagnoses of spindle cell tumors. Immunostaining is helpful to differentiate those entities to obtain a definitive diagnosis and proper treatment. © 2021 Anindhita Muthmaina, Ery Kus Dwianingsih, Shinta Andi Sarasati, Hendry Purnasidha Bagaswoto, Hasanah Mumpuni.