Tehran University of Medical Sciences Acta Medica Iranica 0044-6025 56 4 2018 04 09 272 277 EN Ali Zare Mehrjardi Department of Pathology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran. Sima Fakhari Department of Pathology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran. Mahdi Alem Rajab Department of Surgery, School of Medicine, Iran University of Medical Sciences, Tehran, Iran. 2016 12 11 2017 03 30 Cavernous hemangioma of the colon is a rare vascular malformation but is clinically important because it can sometimes cause massive bleeding. We report a case of thrombocytopenia in a post-partum young woman with large cavernous hemangioma of the ileum and colon, culminating in Kasabach Merritt syndrome (KMS), massive uncontrollable hemorrhage, and death. CT scan shows multiple submucosal bulgings in all segments of the colon. Macroscopic examination showed multiple well-defined masses, with gray-brown color in ileum, cecum and ascending colon. The masses were found to be a cavernous hemangioma with a thick fibrotic wall and extensive intra-cystic hemorrhage. KMS is an uncommon complication of colonic large hemangiomas that, as in our patient, can lead to uncontrollable bleeding and death and should be kept in mind by visceral surgeons as one differential diagnosis of large intra-abdominal tumorous masses, especially in young adults. https://acta.tums.ac.ir/index.php/acta/article/view/6054 https://acta.tums.ac.ir/index.php/acta/article/download/6054/5081