The Diagnostic and Follow-Up Value of Contrast-Enhanced Ultrasound of IgG4-Associated Hepatic Inflammatory Pseudotumor: A Case Report and Review.

IgG4-related hepatic inflammatory pseudotumor (IgG4-HIPT) represents a rare hepatic manifestation of IgG4-related disease (IgG4-RD) and is frequently misdiagnosed at initial presentation. We report the case of a 58-year-old man with a history of autoimmune pancreatitis (AIP) who presented with incidentally detected multiple hepatic lesions. Serum IgG4 was markedly elevated to 7546.6 mg/L. Contrast-enhanced ultrasound (CEUS) suggested cholangiocarcinoma, contrast-enhanced computed tomography (CECT) and magnetic resonance imaging (CEMR) favored hepatic abscesses, while 18F-FDG PET-CT supported an inflammatory process. As the patient declined biopsy, a clinical diagnosis was made based on prior IgG4-RD, serological findings, and multimodal imaging features, and empirical immunosuppressive therapy was initiated. Subsequent follow-up demonstrated significant lesion regression. Although histopathological confirmation was unavailable, the constellation of clinical, serological, and imaging findings was consistent with a presumptive diagnosis of IgG4-related hepatic inflammatory pseudotumor. This case offers important insights into the imaging differentiation and noninvasive management of IgG4-HIPT.