Thymic haemangioma presenting with a left innominate vein aneurysm: insight into the aetiology.

Thymic haemangiomas and innominate vein aneurysms are rare with only 7 and 19 previous cases, respectively, reported in the medical literature. The aetiology of an innominate vein aneurysm remains unclear and there is no previous report of tumour involvement. We present the case of a 27-year old male with concomitant mediastinal tumour and innominate vein aneurysm who underwent surgical treatment. The tumour intruded into the lower section of the innominate vein, thus causing aneurysmal dilation. Pathologically, the tumour was diagnosed as a thymic cavernous haemangioma involving the left innominate vein. This is the first case of a thymic haemangioma presenting with an innominate vein aneurysm, and suggests that tumours may be involved in the aetiology of innominate vein aneurysms.