Intimal sarcoma of the pulmonary vein with left atrial extension: a case report and diagnostic relevance of MDM2.

Intimal sarcoma is an uncommon, aggressive neoplasm originating in the tunica intima of large vessels. Although most cases arise in the pulmonary artery, primary involvement of the pulmonary veins is exceptional. We present the case of a 52-year-old woman who presented to the emergency department with acute heart failure and dyspnoea. Imaging studies initially suggested an atrial myxoma. Surgical resection of the lesion revealed a proliferation characterised by a relatively monotonous spindle-cell proliferation within the pulmonary vein and a separate zone showing greater pleomorphism, necrosis, and atypical mitoses within the left atrial cavity. Immunohistochemistry demonstrated nuclear positivity for MDM2, supporting the diagnosis. Pulmonary vein intimal sarcoma is an extremely rare entity that can be challenging to diagnose. Detection of MDM2 by immunohistochemistry is a key diagnostic tool.