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 .