A 71-year-old woman presented with pericardial discomfort while coughing, and chest computed tomography (CT) showed a left lateral mediastinal mass. Although the mass remained unchanged in CT findings 3 months later, surgical resection was recommended because a mediastinal tumor such as thymoma or teratoma was suspected. The anterior mediastinal mass was 2.0 × 1.2 × 1.8 cm in size, with border regularity and without calcification. Its interior was partially enhanced (Fig. ), and a tortuous vessel was revealed in the thymus in enhanced CT imaging (Fig. ).\nSurgical resection was performed for the purpose of providing a definitive diagnosis and treatment. With the patient in a spinal position, partial resection of the thymus including the mass was done by utilizing a three-port, left-sided VATS approach with hoisting of the third rib. A wine-colored mass bulging from the surface of the left lobe of the thymus was identified (Fig. ) along with the communicating vessel (Fig. ), which could only be cut with an energy device. The operative time was 138 min and there was only minor blood loss. The patient was discharged on postoperative day 7 without complications.\nThe size of the excised mass was 2.3 × 1.3 × 1.8 cm, and there was no infiltration of the adjacent thymus (Fig. ). A histopathological diagnosis of CH in the thymus was made based on the marked dilated vascular channels full of blood covered with endothelial cells and without atypia (Fig. ), and the vessel was included in the mass.\nCH is not a vascular tumor, but rather a congenital vascular anomaly classified as a venous malformation in the low-flow lesion category by the International Society for the Study of Vascular Anomalies (ISSVA) [, ]. This abnormality can occur throughout the whole body, though size and site of origin vary. Some reports have noted its occurrence in patients with a venous aneurysm [, ]. Such a vascular anomaly is considered to be the result of local abnormal morphogenesis of normal vascular endothelial cells occurring before birth [], which then increases in size and exists for the lifetime of the individual without atrophy. Approximately half of the patients with CH are diagnosed at younger than 20 years old. Histopathological findings generally show cavernous or cystic venous channels with a flat single layer of endothelial cells without atypia or mitosis. The choice of treatment is dependent on the related organ and can include embolization, sclerotherapy, and surgical resection. In cases of resection, the lesion should be completely removed because residual tissue has the potential for recurrence with abnormal vessel dilation or regeneration.\nCH occurs with greater frequency in the liver, accounting for approximately 30 % of known cases, as well as in the brain and skin, whereas there are several reports of mediastinal cases in Japan []. Since it was previously thought to be a tumor, a mediastinal CH is considered to be rare, accounting for 0.5 % or less of all mediastinal tumors []. Furthermore, there are only seven reports of cases with a proven thymic origin [, , –].\nWhen occurring in the thymus, a CH may require resection for diagnosis and treatment, as it is otherwise difficult to distinguish from another type of mediastinal tumor such as a thymoma. Even though it does not generally invade the neighboring tissue, complete resection is desirable, as previously described. Cohen et al. reported that subtotal excision should be chosen if complete resection carries serious risk because there was no rapid growth noted in a case of incomplete resection and re-resection can be considered at the time of recurrence []. Extirpation by means of a median sternotomy or thoracotomy will be needed in cases with a giant mass [] or innominate vein aneurism [, ]. On the other hand, thymic partial resection using VATS is a better option for small and non-infiltrative lesions, such as seen in the present case.\nFor accurate diagnosis of CH, magnetic resonance (MR) imaging or ultrasound sonogram are often used to examine the brain, liver, and other organs. The typical imaging manifestation of CH is popcorn-like lesion with a peripheral hypointense rim so-called hemosiderin rim on T2-weighted MR images. As for mediastinal or lung vascular anomalies, enhanced CT may be very effective, as it can reveal a phlebolith in some cases of venous malformation. No phlebolith was seen in our patient, while the center of the mass was enhanced and a communicating vessel running through the thymus was detected. In addition, findings obtained with a three-dimensional image analysis system (SYNAPSE VINCENT ver. 4.0, Fujifilm Medical Inc., Japan) showed the positional relationship of the tortuous vessel and the mass on the side wall (Fig. ). We consider that such an image analysis system is helpful for diagnosis of vessel malformation, as seen in the present case.\nThe mass was resected completely but we intend to follow the present patient to note vessel changes.
A 55-yr-old male presented with acute chest pain, dyspnea, and hypotension on December 8, 2009. The patient has been followed without any medications for incidentally detected asymptomatic SVC aneurysm for last 2 yr (, and the size of the SVC aneurysm did not change (). Chest radiography at admission showed marked widening of the right middle mediastinum due to abnormal soft-tissue density suggesting the rapid expansion of previously noted SVC aneurysm (). Echocardiography revealed marked enlargement and hypokinesia of the right ventricle (RV) with moderate pulmonary hypertension suggesting acute PE. Chest computed tomographic angiography (CTA) showed about 6.9 × 6.1 × 9.9 cm sized lobulated giant saccular aneurysm originating from mainly SVC and partially involving left brachiocephalic vein with internal thrombi (). Considerable amounts of thromboembolic filling defects in left pulmonary artery, both left and right lobar, segmental, and subsegmental arteries were also noted (). Three-dimensional reconstruction with endovascular views showed the giant saccular SVC aneurysm with 4.1 × 3.7 cm sized internal thrombi, and the thrombi protruded into the SVC through the narrow aneurysmal neck (). Venous CTA of the lower extremities and abdominal CTA showed no evidence of deep vein thrombosis or other venous aneurysms. To exclude the possible hypercoagulable status as a cause of pulmonary thromboembolism, the laboratory tests for hypercoagulability was done and revealed no abnormalities. Surgical exclusion of SVC aneurysm with pulmonary embolectomy was planned, but the patient and family refused surgery. Therefore, thrombolytic therapy using recombinant tissue plasminogen activator with the dose of 200 mg was administered intravenously for 2 hr for hemodynamically significant PTE, and the RV function and pulmonary artery pressure was normalized on FU echocardiography. However, the patient complained recurrent chest pain and dyspnea on the next day. FU CTA revealed more decreased amounts of thrombi in the left pulmonary artery and its branches, but the amounts of thrombi in the SVC aneurysm, SVC, right pulmonary artery and its branches were increased. Mobilization of thrombi from the SVC aneurysm due to thrombolytic therapy was the possible cause of recurrent PTE, and it was expected that further embolization of thrombi would be fatal to the patient. Therefore, surgical treatment was strongly recommended. Resection of SVC aneurysm and pulmonary artery embolectomy were performed successfully. At surgery, femoral arterial and venous cannulation was done to prepare for accidental rupture of aneurysm during sternotomy. After dissection of the aneurysm, the other venous cannulation at the innominate vein and isolation of the proximal and distal portion of the aneurysm was done. Under cardiopulmonary bypass, aneurysmal wall was opened longitudinally after snaring of proximal and distal portion of the aneurysm and innominate vein. Aenurysm which contained fresh thrombi was thin-walled and had relatively normal venous endothelium grossly (), and the histopathologic examination showed compatible findings of true aneurysm (). Thin-walled aneurysmal wall was completely resected and subsequent reconstruction of the superior vena cava was performed with glutaraldehyde fixed autologuous pericardium that was already harvested. Outer surface of the pericardium was buttressed with Dacron to prevent potential formation of pseudoaneurysm. A transverse arteriotomy was made in the pulmonary trunk to the left main pulmonary artery and another incision was made in the right main pulmonary artery, and the fresh and organized thrombi were gently extracted. Following the successful surgical management, the mediastinal widening on chest radiography was normalized () and the patient was recovered without any postoperative events. The patient was discharged and treated by anticoagulation with warfarin for 6 months to achieve complete resolution of the possible remained pulmonary arterial thrombi.