Small polypoid lesions of the gallbladder. Differential diagnosis and surgical indications by helical computed tomography

Objectives: To demonstrate the helical computed tomographic (CT) features of small polypoid lesions of the gallbladder and to establish a clinical strategy based on CT findings for the treatment of such lesions. Design: Validation cohort study. Setting: Tertiary care public hospital. Patients: Thirty-one patients with polypoid lesions of the gallbladder (≤3 cm) underwent CT followed by resection. Main Outcome Measure: The detectability of the lesions on both unenhanced and enhanced CT and the configuration of the lesions on enhanced CT were prospectively evaluated in comparison with the histopathological findings. Results: Unenhanced CT detected 14 (45%) of the 31 lesions, whereas enhanced CT detected all of the lesions. The detection rates of the neoplastic lesions (adenoma, adenocarcinoma, and metastatic tumor) and cholesterol polyps were 81% (13/16) and 7% (1/15), respectively (P<.001). Among the 20 lesions demonstrated as pedunculated, 6 (30%) were neoplastic, whereas 10 (91%) of the 11 lesions demonstrated as sessile were neoplastic (P<.001). When a lesion was demonstrated on unenhanced CT or its shape was sessile on enhanced CT, the case was diagnosed as a neoplastic lesion. The sensitivity, specificity, positive predictive value, negative predictive value, and overall accuracy of the CT diagnosis of the neoplastic lesions were 88% (14/16), 87% (13/15), 88% (14/16), 87% (13/15), and 87% (27/31), respectively. Conclusion: Computed tomography can differentiate neoplastic and nonneoplastic small polypoid lesions of the gallbladder and reliably identify the presence of neoplastic lesions that should be resected.