Cardiac leiomyosarcoma in a 66-day-old infant: a case report

Primary cardiac tumors are very rare in infants. Most of them are benign, such as rhabdomyoma. Malignant tumors like leiomyosarcoma are extremely uncommon in this age group. Their symptoms are often non-specific, which makes diagnosing them challenging. A 66-day-old female infant (38 weeks’ gestation; weight 5 kg) presented with fever, cough, diarrhea, and poor feeding. On admission, she exhibited respiratory distress, tachypnea (65 breaths/min), tachycardia (160 beats/min), cyanosis during crying, and oxygen saturation of 85% on room air. Initial evaluation revealed massive pericardial effusion on chest radiography, and Computed Tomography (CT) angiography demonstrated a right atrial mass. Due to the life-threatening condition, emergent surgical intervention was performed without delay for neoadjuvant therapy. A large friable tumor measuring 50 × 70 × 40 mm, involving the right atrial wall and tricuspid valve, was identified and extensively resected. Because of tumor invasion into the atrioventricular groove (AV), the right coronary artery (RCA) was mobilized to facilitate tumor removal while preserving coronary integrity. The tricuspid valve was reconstructed using an autologous pericardial patch, and the right atrium was reconstructed with a bovine pericardial patch. Histopathological and immunohistochemical (IHC) evaluations confirmed a high-grade primary cardiac leiomyosarcoma with high mitotic activity and a Ki-67 proliferative index of 30–40%. Postoperatively, the infant developed Serratia sepsis, which was successfully treated, and she was transferred to the oncology ward for further management. This case underscores the diagnostic difficulty and the surgical complexity of cardiac leiomyosarcoma in infants. Management required aggressive surgical resection involving the right atrium, tricuspid valve, and mobilization of the RCA, followed by extensive pericardial reconstruction. Although an R0 resection was not achievable, urgent surgical decompression with R1 resection was life-saving and permitted subsequent adjuvant chemotherapy.