Portal Biliopathy and Cavernous Transformation of the Portal Vein Revealed by 68Ga-FAPI PET/CT

Abstract

A 47-year-old man presented with right upper abdominal pain for 1 month. Contrast-enhanced CT revealed hilar bile duct stenosis with dilatation of the intrahepatic bile ducts, and his serum CA19-9 and CA242 levels were significantly elevated. 18 F-FDG and 68 Ga-FAPI PET/CTwere performed for differential diagnosis. 18 F-FDG PET/CT showed only mild FDG uptake in the hepatic hilum. Astonishingly, in 68 Ga-FAPI PET/CT, intense radioactivity was presented on the same region, which indicated massive fibroblasts aggregation in hepatic hilum. The patient was finally diagnosed as portal biliopathy caused by cavernous transformation of the portal vein.

68Ga-FAPI PET/CT Provides a Clear Picture of a Klatskin Tumor That 18F-FDG PET/CT Missed

“…In this case, the relatively novel radiotracer, 68 Ga-labeled FAPI, was successful in assessing primary Klatskin tumor and avoided the well-known false-negative pitfall of the more traditional 18 F-FDG, particularly for the histological mucinous subtype 1,2 . Indeed, this was in line with the expectations of colleagues in the field who have explored the comparable utility of 68 Ga-FAPI PET/CT in the oncologic field generally, as well as for tumors of biliary origin specifically 3–9 . According to Dendl et al, among others, the explanation could be found in the relatively unique tumor microenvironment of the major cholangiocarcinoma subtypes and the associated abundance of desmoplastic reactions and cancer-associated fibroblasts 10,11 .…”

“…1,2 Indeed, this was in line with the expectations of colleagues in the field who have explored the comparable utility of 68 Ga-FAPI PET/CT in the oncologic field generally, as well as for tumors of biliary origin specifically. [3][4][5][6][7][8][9] According to Dendl et al, among others, the explanation could be found in the relatively unique tumor microenvironment of the major cholangiocarcinoma subtypes and the associated abundance of desmoplastic reactions and cancer-associated fibroblasts. 10,11 This, combined with FAPI's significantly lower background (liver) uptake, results in excellent target-to-background ratios and, as a result, improved sensitivity for not only the primary tumor, but also metastatic nodal and distant carcinomatosis.…”

FAPI PET/CT in the Diagnosis of Abdominal and Pelvic Tumors

“…A final laparotomy resulted in a diagnosis of portal vein biliary lesions caused by cavernous portal degeneration. In this case, the uptake rate of portal cholangiopathy caused by cavernous portal degeneration was higher on 68 Ga-FAPI PET/CT than on 18 F-FDG PET/CT ( 82 ). A 57-year-old man with a history of colon cancer resection showed enhanced FAPI uptake in the gallbladder wall with a central area of reduced signal on 68 Ga-FAPI PET/CT.…”

Diagnostic and Therapeutic Application of Fibroblast Activation Protein Inhibitors in Oncologic and Nononcologic Diseases

“…The gallbladder typically shows low physiologic FAPI uptake. Reported nononcologic FAPI uptake includes IgG4-related sclerosing cholangitis (average SUV max : 9.4) 37 and portal biliopathy (SUV max : 8.2) due to cavernous transformation of the portal vein 79 …”