Probe-Based Confocal Endomicroscopy in Primary Sclerosing Cholangitis: Not All Inflammatory Strictures Are the Same

Primary sclerosing cholangitis (PSC) frequently causes inflammatory strictures (IS). The Paris Classification (PC) for probe-based confocal laser endomicroscopy (pCLE) identifies four descriptive criteria of IS. We aim to compare the pCLE findings of IS in PSC and non-PSC patients.

This is a single-center, retrospective review of all histologically proven IS evaluated with pCLE with at least 6 months of follow-up. All pCLE images were reviewed for each criteria of the PC: (1) vascular congestion, (2) dark granular pattern, (3) increased inter-glandular space, and (4) thickened reticular structures (TRS). The clinical status (PSC vs. non-PSC) was blinded to the reviewer. Univariate, multivariate, and stepwise logistic regression analyses were conducted. The primary outcome was the number of PC criteria present in PSC versus non-PSC.

A total of 35 patients (13 PSC, 22 non-PSC) were included (mean age 59.1 years, 25.7 % male). Each of the PC criteria was present more frequently in non-PSC patients. The presence of TRS was significantly different (95 vs. 62 %, p = 0.01). All patients had at least two criteria present, but non-PSC patients had a significantly higher frequency of three criteria (95 vs. 38 %, p < 0.001) and four criteria (55 vs. 23 %, respectively, one-tailed p = 0.03) present.

In patients with IS, the individual and combined components of the PC are present in higher frequency in non-PSC patients. The presence of TRS is 13 times more likely to predict non-PSC etiologies. Refined pCLE criteria may be required to evaluate IS in patients with PSC.

NCT02166086.