Case report
An 18-year-old young lady with mild dyspnea and a 15-day history of treatment with a preliminary diagnosis of respiratory infection was admitted to our hospital. The diagnosis of pneumonia was suspected. In this context, a computerized tomographic (CT) scan revealed a 4 x 2,5 cm mass, involving the left atrium and the right inferior pulmonary vein, suggesting an intracardiac neoplasm. The patient was referred to us with a suspected diagnosis of a left atrial tumor. This was confirmed by a cardiac magnetic resonance imaging (MRI) that also showed a 4.4 x 3 x 2.2 cm mass in the left atrium extending to the right inferior pulmonary vein with gadolinium enhancement. A transthoracic and transesophageal echocardiogram showed a mass with little mobility in the left atrium extending to the right inferior pulmonary vein (Figure 1). The tumor was not obstructive, and both ventricular functions were preserved. We performed positron emission tomography (PET) CT to exclude malignancy and metastasis. PET CT revealed high fludeoxyglucose (FDG) uptake, and surgery was planned.
Because of the possible necessity for lung resection, the right submammarian thoracotomy approach was chosen. A double-lumen endotracheal tube was placed for unilateral ventilation during surgery. A right sub-mammary skin incision was performed to avoid damaging the mammary gland, after that subcutaneous fat and mammary gland were dissected from the fascia to expose the 4th rib. After unilateral lung ventilation was initiated, the pericardium was opened vertically 1.5-2 cm anterior to the right phrenic nerve and suspended to ensure adequate exposure. After heparin was administered, aorta cannula was placed in the ascending aorta, and bicaval venous cannulas were inserted via the same thoracic incision. The cardioplegia needle was placed into the aortic root from the thoracic incision, and cardiopulmonary bypass (CPB) was started with mild hypothermia. A Chitwood clamp was used through the 4th intercostal space to clamp the ascending aorta, and cold blood cardioplegia was given. After the heart was arrested, the right atriotomy incision was performed, the interatrial septum was opened and the mass in the left atrium was reached. The tumor had a stable consistency, there was no necrosis or ulceration on its surface, and it was gently attached to the left atrial wall with a thin capsule. The tumor extended to the bifurcation of the right lower pulmonary vein branches, and it could be excised entirely with its stalk (Figure 2). Cold saline was used to rinse the heart chambers, and careful examination was performed to ensure complete resection. After the de-airing procedure, the interatrial septum and the right atriotomy was closed primarily. The aortic cross-clamp was removed, and the heart was reperfused.
The tumor was evaluated with the frozen section examination but couldn’t be classified as benign or malignant neoplasm during the operation. Therefore, we didn’t perform lymph node dissection and right lower lobectomy. Cessation of CPB was uneventful, and the thoracotomy was closed. The patient recovered smoothly, she was transferred to ward on postoperative day 1, and discharged from the hospital on postoperative day 6. On the histopathologic evaluation, multiple sections revealed pleomorphic spindle tumor cell fascicles with nuclear hyperchromasia. Atypical mitosis was seen (14 mitotic activity/10 HPF) with coagulation necrosis. Actin and Desmin were positive for reaction, but CD34 and S100 were negative (Figure 3). A total of 30% positivity was shown by tumor cells for Ki-67, and these morphological features were consistent with a diagnosis of leiomyosarcoma.
After histopathologic confirmation of leiomyosarcoma, we planned right lower lobectomy to be sure complete resection of the tumor and to prevent a recurrence. The same incision was used. Right lower lobectomy with right inferior pulmonary vein excision, mediastinal lymph node dissection and partial left atrial resection was performed without CPB. The samples of tissues were taken from the surgical margin. The thoracotomy was closed, and the patient was transferred to the cardiovascular intensive care unit. The postoperative period was uneventful, and the chest tube was removed on postoperative day 5. The patient discharged from the hospital on a postoperative day 7. Histopathological examination revealed that the resected pulmonary vein and left atrial specimen borders were histologically clear.
Thorax and abdomen MR scans revealed no metastases in the postoperative early period. According to a multidisciplinary staff, adjuvant chemotherapy consisting of four cycles of Doxorubicin and Ifosfamide was prescribed by the medical oncology department. Moreover, she had adjuvant cardiac radiotherapy (54 Gy in 27 fractions) at postoperative 5th month. The patient is regularly followed, no metastasis was detected in PET CT and thoracic MR scans, after 4 and 6 months follow up, respectively. After a follow-up of 12 months, she still has no clinical or radiological evidence of recurrence.