Descending aortic stenosis caused by intramural thrombus in the setting of severe thrombocytosis: a rare mimicker of aortic angiosarcoma.

A rare case of descending aortic stenosis caused by intramural thrombus in a patient with severe thrombocytosis is presented. A 50-year-old man exhibited progressive bilateral claudication. Imaging revealed a suspicious intramural lesion with no significant enhancement on positron emission tomography-computed tomography scans. Because primary aortic angiosarcoma could not be excluded, an oncological surgical strategy was used. The lesion was removed en bloc without luminal entry, and a 22-mm Dacron graft was used for reconstruction. Histopathological analysis confirmed thrombus without malignancy. Postoperative recovery was uneventful, with resolution of claudication, normalization of the ankle-brachial index (ABI) and ongoing cytoreductive therapy for confirmed essential thrombocythaemia. This case highlights the importance of considering haematologic disorders in aortic pathology and demonstrates a safe surgical strategy in diagnostically uncertain cases.