Colonoscopy For the exact diagnosis, colonoscopy was performed. Colonoscopy revealed marked, circumferential submucosal varix with easy-touch-bleeding. These findings were compatible with diffuse cavernous hemangioma. Thus, this lesion was clinically confirmed as diffuse cavernous hemangioma involving sigmoid colon.

Colon Hemangioma Uncommon benign vascular tumor Anywhere in GI tract : jejunum (m/c), recto-sigmoid (2nd) Children and young adult Sx. : recurrent, intermittent painless rectal bleeding (m/c) abdominal pain, mechanical obstruction, intussusception, perforation ► Pathologic classification ▪ capillary ▪ cavernous (80% of recto-sigmoid) I will briefly review for colon hemangioma. Gastrointestinal hemangiomas are uncommon benign vascular tumors, that may occur anywhere in the gastrointestinal tract. Jejunum is the most common site, and rectosigmoid colon is the next common site. It affects mainly children and young adult, and the most common symptom is known as recurrent intermittent painless rectal bleeding. Histollogically, there are two priciple types. Capillary hemangiomas are a proliferation of small capillaries. Cavernous hemangiomas consist of large blood-filled spaces or sinuses, and it may infiltrate large segments of the intestine and mesentery. In rectosigmoid hemagioma, cavernous hemangioma is dominant type.

► Growth patterns ▪ solitary polypoid ▪ multifocal polypoid ▪ infiltrative, annular growth with intraluminal & extraserosal Intestinal hemangioma has three different growth pattern, resulting different imaging spectrum. Intestinal hemangioma can manifest as intraluminal polypoid or infiltrative growing lesion. Especially, infiltrative lesion can growth to extraserosal space.

► Imaging findings of recto-sigmoid hemangioma - 80% cavernous hemangioma → infiltrative growth pattern → rigid annular lesion → mimics carcinoma. - Phlebolith : degenerative change (calcified thrombi), virtually pathognomic ! characteristic multiple phleboliths (26-50%) on simple radiograph As mentioned earlier, cavernous hemangioma is the dominant histologic type in rectosigmoid hemangioma. Thus, this histologic type can show the infiltrative growth pattern, forming rigid annular lesion. Clinically, it can mimic rectosigmoid carcinoma. However, the phlebolith, calcified thrombi, is known as pathognomic feature for hemangioma. Thus, the presence of phlebolith help us to differentiate infiltrative subserosal growing hemangioma from carcinoma. It is known that this characteristic multiple phleboliths can be detected on simple radiograph, in about thirty to fifty percent cases.