On a double-contrast barium enema, a smooth, well-circumscribed, round, 1.5 cm filling defect with a broad base and intact overlying mucosa is seen in the descending colon. It is mobile on compression. Which diagnosis does this MOST likely represent?

• A Colonic lipoma ✓
• B Colonic adenomatous polyp
• C Colonic carcinoma
• D Endometriosis nodule

Explanation

B colonic lipoma appears as a smooth, round, well-circumscribed filling defect with a broad base, intact mucosa, and characteristic mobility on compression because it is a soft, submucosal fat-density lesion. CT would confirm negative Hounsfield units. Adenomatous polyps are usually pedunculated with a stalk or have a lobulated surface, not a smooth broad-based submucosal contour. Colonic carcinoma produces an irregular, fixed, apple-core lesion with mucosal destruction. Endometriosis produces an extrinsic, fixed indentation with normal mucosa.

Reference: Gore and Levine's Textbook of Gastrointestinal Radiology, 4th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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