chest pa showed superior mediastinal widening and bulging of the right paraspinal interface ( fig .
1 ) . increased opacity of the infrahilar window and thickening of the posterior wall of the bronchus intermedius were seen on the lateral chest x - ray .
an oval - shaped mass measuring 9.73.86.0 cm was seen in the left superior mediastinum .
a bizarre - shaped vascular structure that was connected to left innominate vein was seen in central area of the mass ( fig .
the mass showed insinuating appearance without significant compression of adjacent structures . only the thymus was slightly compressed by the mass .
another similarly natured mass was seen in the right paraspinal area , which measured about 4.23.06.6 cm .
this mass also contained a bizarre - shaped vascular structure that communicated with the left atrium directly through an anomalous vascular structure ( fig .
2 ) . multiplanar reconstruction ( mpr ) and 3d reformation showed that the contrast directly entered the vascular components of the masses via an abnormal vein originating from the left innominate vein ( fig .
the mediastinal window setting of contrast - enhanced ct showed additional multiple small cystic lesions in the middle mediastinum .
a two - stage operation was planned due to the fact that the tumors were located bilaterally .
first , for the left side tumor resection , posterolateral thoracotomy was performed and a large cystic mass was found in the anterosuperior mediastinum .
the content of the cyst was bloody and a large communicating vein to left innominate vein and few small communicating veins to left intercostal veins were found , which were then ligated and divided .
the second operation was performed for the right mediastinal mass 45 days after the first surgery .
the right paraspinal mass was successfully resected and an anomalous communicating vein to left atrium was identified and divided .
the patient recovered completely without any complications such as chylothorax or hemothorax . on gross pathologic examination , the cut surface of the tumor revealed numerous cystic spaces and a cavernous sinus containing bloody contents ( fig .
histology of the mass showed combined proliferation of venous vascular channels ( ve ) and lymphatic channels ( ly ) that exhibited infiltration into mediastinal fat pad ( fig .
mediastinal lymphangiohemangioma is a very rare venolymphatic malformation containing both vascular and lymphatic elements . direct vascular communication between the lesion and the vena cava system
ct images of the mediastinal lymphangiohemangioma are very rarely found in the english literature [ 1 - 4 ] . moreover ,
neither a case with multiple masses and more than one vascular communication nor a case directly connected to the heart chamber through an anomalous vessel was found in the literature .
we report a case of surgicopathologically confirmed mediastinal lymphangiohemangioma that communicated with the left innominate vein and left atrium directly via anomalous vascular structures ( fig .
vascular malformations are subcategorized as lymphatic , capillary , venous , arteriovenous , and mixed malformations on the basis of their histologic nature .
. therefore , our case can be categorized as low - flow vascular malformations with mixed lymphatic and venous components .
slow - flowing blood appears as high signal intensity on t2-weighted images and as intermediate signal intensity on t1-weighted images .
most lesions present early in childhood and the most common locations for lymphatic malformations are the neck and axilla .
a less common location is the mediastinum , and the anterior mediastinum is the most commonly found mediastinal site .
ct scan , the mass showed diffuse low attenuation without calcification , although previous reports showed scattered phleboliths in the mass , which represent calcified emboli in the venous channels .
the anomalous vascular structures were enhanced at the same intensity as the systemic venous system and was connected directly to the left innominate vein and left atrium .
the peripheral portion of the lesion was not enhanced on all phases of dynamic ct scan , which may be related to the lymphatic components or fibroconnective tissues of the mass .
a previous report postulated that the anomalous vein acts not only as a draining vessel but also as a feeding vessel . in our case , only the proximal part of the vascular structure was enhanced on the pulmonary arterial phase , whereas all of the large bizarre - shaped vascular spaces were enhanced on the systemic venous phase ( fig .
2 ) . a delayed ct scan may show delayed clearance of contrast within the anomalous venous channels because of the lack of smooth muscle in these channels .
lymphangiohemangiomas are not considered an congenital anomaly but are frequently associated with other vascular malformations , most commonly in the left superior vena cava . in our case ,
the anomalous vessels connected to the left innominate vein may be considered a left superior vena cava remnant .
a lymphangiohemangioma should be included in the list of differential diagnoses of an incidentally found low - attenuating mediastinal mass , especially in young patients .
another therapeutic option is percutaneous sclerotherapy using agents such as absolute ethanol , bleomycin , cyclophosphamide , doxycycline , alcohol solution of zein , or ok-432 . recognizing that the lesion is a low - flow vascular malformation is more important than determining whether the lesion is predominantly venous or lymphatic when making treatment decisions .
we planned surgical excision of the lesions and successfully excised them without any complications such as hemothorax or chylothorax .
for successful surgery , the anomalous vascular pedicle of the mass communicating with the systemic vein or heart chamber should be carefully identified and divided to prevent massive hemothorax .
 lymphangiohemangiomas of the mediastinum are exceedingly rare and few cases have been published in the english literature . 
 this report may be the only reported case in which lymphangiohemangiomas were found bilaterally . 
 we report a case of a 7-year - old boy with an incidental finding of an abnormal mediastinal shadow on a chest x - ray . 
 the chest ct showed a large mass in the left superior mediastinum and another in the right posterior mediastinum . 
 the left mass had anomalous venous channels connected to the left innominate vein , and the right mass to the left atrium . 
 we performed an excision of the mass in the left side first and then the right side one month later . 
 anomalous venous channels were dissected carefully and ligated . 
 there were no complications and no signs of recurrence 30 months after the operation . 
CASE REPORT
DISCUSSION