What condition is characterized by significant dilation of the entire colon with preserved haustral markings?

The condition characterized by significant dilation of the entire colon with preserved haustral markings is indeed Ogilvie syndrome. This syndrome, also known as acute colonic pseudo-obstruction, presents with massive colonic distension in the absence of a mechanical obstruction.

In Ogilvie syndrome, an important feature is the presence of haustral markings on imaging, indicating that the colonic wall is not completely obstructed and that the underlying muscular layer remains intact. This distinguishes it from conditions that cause true mechanical obstruction, where these markings may be lost due to wall edema, inflammation, or tumor infiltration.

Cecal volvulus, on the other hand, typically presents with distension localized to the cecum and may show loss of haustral markings due to obstruction. Diverticulitis usually involves localized diverticular inflammation and not generalized dilation, and colorectal cancer can present with obstruction but often leads to significant changes in bowel wall appearance, including loss of haustral markings in affected segments.

In summary, Ogilvie syndrome is defined by diffuse colonic dilation while maintaining the architecture of the colon, which is not seen in the other conditions presented.