Cholestasis in a cancer patient: think about the unicorn

A 76-year-old male was referred for ongoing cholestasis of unclear origin. He had a stage IIIA non-small-cell lung carcinoma, treated for six months with adjuvant durvalumab after initial treatment with chemoradiotherapy. Durvalumab was halted three months ago after achieving stable disease for four consecutive months. Cholestasis was moderate with alkaline phosphatase (ALP) 5 x upper limit of normal (ULN), gamma-glutamyltransferase (GGT) 21 x ULN and normal bilirubin. There was one single episode of spontaneously transient postprandial abdominal pain a couple weeks before, besides absence of fever and pruritus. Viral serology and an auto-immune panel were negative, IgG4 was low. Computed tomography (CT) evaluation during his oncological follow up is shown in Figure 1. Relevant findings of an endosonographic (EUS) evaluation are shown in Figure 2.