<prompt> Cobble stoning of intestine with string sign of kantor is seen in:Crohns diseaseUlcerative coitisIshemic colitisAmoebic colitic  <response>: Ans. A. Crohns disease Cobble stone mucosa is appearance of the intestinal mucosa in Crohns disease to the endoscopist, Cobblestoning refers to the uniform nodules-due to the sub-mucosal fibrosis. String sign of Kantor is due to involvement of the terminal ileum in Crohns disease. It is caused by severe spasm due to irritability of the loop producing the appearance of a frayed cotton string. Subsequently the wall of the ileum may become fibrotic and the lumen fixed in diameter. 