2026 年 10 巻 2 号 p. 74-80
Extramedullary lesions of pediatric acute lymphoblastic leukemia (ALL) can present as tumorous masses outside the bone marrow and, in rare cases, may occur within the cardiac chambers. We report a case of a 14-year-old girl previously diagnosed with ALL at the age of 12 years. At that time, chest CT and echocardiography performed as part of a systemic evaluation revealed multiple masses approximately 20 mm in size in the right atrium and right ventricle, raising suspicion of extramedullary involvement of ALL. Due to poor general condition, surgical intervention was deferred in favor of prioritizing chemotherapy for the underlying disease. Serial follow-up using echocardiography and electrocardiography demonstrated no significant change in tumor size, and the patient’s overall condition remained stable. After induction of remission, pulmonary perfusion scintigraphy was performed for the first time, revealing a segmental perfusion defect in the right lower lobe, leading to a diagnosis of asymptomatic pulmonary embolism (1 year and 6 months after leukemia onset). Given the presence of multiple residual masses within the cardiac chambers, surgical resection was performed, and several nodular lesions were removed. Pulmonary embolism associated with intracardiac extramedullary lesions of ALL may be life-threatening. To prevent tumor detachment and embolization, early surgical resection should be considered in conjunction with systemic treatment of the underlying malignancy.
