Gallbladder polyps are lesion protruding into the lumen from the gallbladder wall.
Gallbladder polyps are common ultrasound findings. The prevalence has been reported
up to approximately 5 % [1]
[2] but also reported higher [3].
Most polyps are benign lesions, still malignant transformation is a concern. Gallbladder
polyps are typical an asymptomatic condition with benign appearance. Inflammation,
skinfolds and cholecystolithiasis can be misinterpreted as polyps during ultrasonography.
Gallbladder cancer has typically a poor prognosis due to its late diagnosis. Data
from GLOBOCAN 2018 reports of 165 000 gallbladder cancer deaths yearly world-wide
[5]. Gallbladder cancer varies significant between ethnic groups, and has been reported
with incidence up to 27/100 000 in American indigenous populations [6]. The risk of malignancy increases in patients with polyp size of > 10 mm, > 50 years
of age, co-existing gallstones and/or rapid polyp growth [4].
Current guidelines recommend surgical removal of the gallbladder if polyps > 10 mm,
due to the increased risk of malignancy, and ultrasound follow-up if the polyp size
is between 6–9 mm [4]. What about the small polyps < 6 mm? A recent gallbladder polyp management study
enhances that the low prevalence of gallbladder cancer and poor understanding of its
natural history has led to inconsistent management policies as most guidelines are
based on retrospective studies with small sample size [7].
A systematic literature review including papers from 1996 to 2011 investigated growth
rate and malignancy in small gallbladder polyps. Most of the studies found no correlation
between growth and development of malignancy.
In 2012 our research group investigated 203 patients (114 woman and 89 men) with gallbladder
polyps (ultrasound scan every 6th months during a two year period) [8]. No malignancy was detected. The polyp mean size was 5 mm, and in 175 (86 %) patients
the polyp size was ≤ 6 mm.
In 2020 our research group investigated long-term follow-up growth in patients with
small polyps ≤ 6 mm, and included 154 patients (100 women and 54 men) [9]. Retrospective ultrasonography reports between 2007–2009 were reviewed, and patients
diagnosed with a polyp less than 6 mm were invited to a 1o-year follow-up ultrasonography.
A total of 15 polyps had increased 2 mm or more during the 10-year period. The mean
polyp size was 4 mm, and no malignancy was detected. Showing that small gallbladder
polyps have low probability of growth. Still, patients with gallbladder cancer have
poor prognosis, and therefore it is important to identify the patients who are at
risk of developing a cancer.
[Fig. 1] shows a gallbladder polyp 7 mm in size adherent to the gallbladder wall with no
acoustic shadowing. No gallstone detected.
Fig. 1
