Polypoid lesions of the gallbladder: analysis of 1204 patients with long-term follow-up.

BACKGROUND: Polypoid lesions of the gallbladder (PLG) are common, and most are benign. Few lesions are found to be malignant, but are not preoperatively distinguished as such using common imaging modalities. Therefore, we compared characteristics of benign and malignant PLGs in depth.

METHODS: We enrolled 1204 consecutive patients diagnosed with PLG at Taipei Veterans General Hospital between January 2004 and December 2013. Patients underwent either surgery or regular follow-up with various imaging modalities for at least 24 months. The mean follow-up duration was 72 ± 32 months.

RESULTS: Of 1204 patients, 194 underwent surgical treatment and 1010, regular follow-up. In addition, 73 % patients were asymptomatic. The mean PLG size was 6.9 ± 7.7 (range 0.8-129) mm; the PLGs of 337 patients (28 %) grew during their follow-up periods. The majority of PLGs (90.4 %) were single lesions, and 10.5 % of patients had associated gallstones. The PLGs of 20.1 % of surgical patients were malignant. Malignant PLGs were found in 32.4 % of patients ≥50 years old and in 4.7 % of those <50 years old (p < 0.001). Right quadrant abdominal pain, epigastric pain, and body weight loss were the three most common symptoms associated with malignancy. Malignant PLGs were significantly larger than benign lesions (means: 27.5 ± 18.4 mm vs. 12.3 ± 12.3 mm, respectively, p < 0.001). Notably, the size of 5 % of malignant PLGs was 3-5 mm, and that of 8 % was 5-10 mm. The negative predictive value for gallbladder malignancy was 92.8 % based on a size ≥10 mm and 100 % based on a size ≥3 mm.

CONCLUSIONS: Our study reassesses the PLG size that warrants more aggressive intervention. Cholecystectomy remains mandatory for PLGs > 10 mm, but should also be considered a definitive diagnostic and treatment modality for PLGs with diameters of 3-10 mm.