We report the case of a 71-year-old man presenting inaugural cholestatic jaundice, with a stricture and circumferential wall thickening of the distal common bile duct, as well as an ill-defned hepatic infltrative mass with “amputation” of peripheral distended bile ducts. The patient underwent a pancreaticoduodenectomy and hemihepatectomy for suspected cholangiocarcinoma. Histology revealed IgG4 associated cholangitis (IgG4-AC) and hepatic pseudoinfammatory tumour (HPT). IgG4-related disease (IgG4-RD) is a recently established systemic disease, characterized by fbro-infammatory tissue infltrates and tumefaction of one or more organs. The hepatobiliary manifestations comprise IgG4-AC and associated HTP - which can be mistaken for cholangiocarcinoma. Clinicians must be familiar with this disorder, usually responsive to corticosteroid therapy, in order to avoid unnecessary invasive procedures. We present a case of IgG4-AC and associated HTP and review the literature of this rare presentation of IgG4-RD.

Keywords: IgG4-related disease; Autoimmune cholangitis; Hepatic pseudoinfammatory tumour; Cholangiocarcinoma; Hemihepatectomy; Cephalic pancreaticoduodenectomy.

The evaluation of sonographically indeterminate adnexal lesions should be performed with MRI (Magnetic Resonance Imaging). It is fundamental to determine the exact location of the lesion, since the differential diagnosis and therapeutic approach are distinct according to the organ of origin. Some signs that may indicate an ovarian origin are: the presence of ovarian follicles and normal ovarian parenchyma surrounding the lesion, without a cleavage plane (“embedded organ sign”); a change in the ovarian contour by the mass (“beak sign”); visualisation of a vascular pedicle or the gonadic veins leading to the lesion (“suspensory ligament sign”); deviation of the iliac vessels laterally and of the pelvic ureters posteriorly or postero-laterally. The majority of ovarian lesions show cystic components with high signal-intensity on T2 weighted-imaging. Hypointense lesions on T2 are less frequent. The differential diagnosis for T2 hypointense ovarian lesions can be vast: haemorrhagic lesions (namely endometrioma); presence of smooth muscle (leiomyoma); presence of fbrous tissue (fbroma, thecoma and cystadenofbroma) and tumours with mixed cellularity (Brenner tumour, “struma ovarii” and Krukenberg tumour).

According to the ESUR recommendations published in 2017, diffusion-weighted imaging (DWI) should be applied for those lesions, using high b-values. The lesions that show lowsignal intensity on DWI are classifed as benign and do not require further investigation. On the other hand, for lesions that demonstrate intermediate or high signal on DWI, it is essential to administrate intravascular contrast, ideally with dynamic-contrast enhanced imaging (DCE).

Keywords: T2-hypointense lesions; Ovarian lesions; MR; Haemorrhagic lesions; Fibrous tissue; Mixedcellularity tumours.