A 43-year-old man from Morocco was admitted to our department for 4 days of painless mucocutaneous jaundice, choluria and generalised pruritus. The only history of interest was a treated tuberculosis, hypercholesterolemia under dietary treatment and mild smoking. Laboratory tests showed the following: bilirubin 19.44 mg/dl, GOT 110 IU/ml, GPT 371 IU/ml, GGT 632 IU/ml, FA 787 IU/ml, LDH 394 IU/ml. Amylase and lipase were normal throughout. Hypergammaglobulinaemia (gamma globulin 1.56%) was also notable, with IgG 1840 IU/ml (751-1560 IU/ml). The CA 19-9 marker was 82 IU/ml. Autoantibodies (ANA, AMA, AMA-2, ANCA, LKM1, SMA, SLA and F-actin) and serologies for viruses and bacteria (HAV, HBV, HCV, HIV, CMV, EBV, VZV, HSV, parotidis virus, parvovirus B19, Brucella, Borrelia, Coxiella, Leishmania, Rickettsiae and Toxoplasma) were negative. Abdominal ultrasound showed dilatation of the intra- and extrahepatic bile duct and echoendoscopy (EUS) showed an enlarged pancreas with a 3 cm focal lesion at the level of the head and mild posterior dilatation of the pancreatic duct. The thoracoabdominal CT scan also showed an overall enlarged pancreas, hypodense, with a hypodense peripancreatic halo, with a smooth border, without involvement of the peripancreatic fat, and, at the retroperitoneal level, in the periaortic location with extension to bilateral iliac territory, a dense tissue surrounding these vascular structures like a case, all of which was compatible with autoimmune pancreatitis with retroperitoneal fibrosis. Given the persistence of pruritus and manifest cholestasis, percutaneous biliary drainage was performed and the cholangiography showed a stenosing lesion in the distal common bile duct suggestive of pancreatic neoplasia. In view of this possibility, as a first differential diagnosis, a fine needle puncture-aspiration guided by EUS was performed with negative cytology for malignant cells and negative Zielh staining. Given the absence of confirmation of neoplasia, and with the suspicion of autoimmune pancreatitis, an endoscopic retrograde cholangiopancreatography (ERCP) was performed, observing dilatation of the main bile duct with a regular stenosis in its distal portion, of about 3-4 cm, of benign appearance, over which a plastic stent was placed. Treatment was started with corticosteroids (methylprednisolone at a dose of 32 mg/day) and the percutaneous drain was removed. With the diagnosis of probable PAI, the patient was discharged and followed up on an outpatient basis, with normalisation of all analytical parameters and resolution in the control abdominal CT scan, at one and four months, of the lesions described initially, with normalisation of the pancreatic size and appearance and disappearance of the retroperitoneal fibrosis. The dose of corticosteroids was progressively reduced until it was completely withdrawn at 4 months, and the biliary stent was also withdrawn. To date, after 24 months of follow-up, the patient has remained asymptomatic with no recurrence of autoimmune pancreatitis or retroperitoneal fibrosis.