Calcified rims. Uncommon radiologic finding and potential pitfall due to organization of deposits of oyster shell tablets.

In a patient undergoing double-contrast barium enema (DCBE) for evaluation of recent onset of diarrhea, a curvilinear strand of calcifications outlining a filling defect of the cecum, initially thought to represent a neoplasm, later was discovered to be due to precipitation and organization of orally ingested calcium in an adherent fecalith. Colonoscopy and repeated x-ray evaluation avoided the pitfall. This case illustrates the need for analysis and correlation of the type of calcifications characterizing a mass in light of the clinical history. Errors in interpretation can be avoided by asking the patient about oral medications and obtaining delayed films. Colonoscopy may be the diagnostic test in doubtful cases.