An Evasive Liver Mass in a Human Immunodeficiency Virus (HIV)-Positive Patient

Abstract

IgG4-related disease (IgG4-RD) is an autoimmune syndrome that is characterized by elevated levels of serum IgG4 and infiltration of various tissue types by IgG4 immunoreactive plasma cells. The IgG4-RD can result in systemic disease and the formation of inflammatory mass lesions, frequently addressed as pseudotumors. While IgG4-RD can manifest in various organs, liver involvement is rare, and because it is an immune-mediated inflammatory process, it is uncommon in patients who are immunocompromised. Furthermore, despite IgG4-RD responding well to immunosuppressive treatment, cases of spontaneous remission are exceedingly rare in the literature. In this report, we present the unique case of a self-resolving IgG4-RD lesion of the liver in a HIV positive patient.

Keywords: IgG4-related disease; immunosuppression; pseudotumor.

Figure 1.

Arterial phase computed tomography demonstrated a large heterogenous mass in the right lobe of the liver measuring up to 11.2 cm (predominantly in segment 7 or 8). Areas of solid enhancement as well as a central necrosis are present. **IgG4-related pseudotumors usually present with variable enhancement patterns, most commonly exhibiting homogenous delayed enhancement.

Figure 2.

Venous phase computed tomography demonstrated right posterior portal vein thrombosis; raising suspicion for a tumor in vein.

Figure 3.

Densely inflamed liver biopsy tissue with storiform pattern of fibrosis (A 100× magnification H&E). Numerous plasma cells in a background of completely replaced hepatic parenchyma by the fibrosis (B 200× magnification H&E and (C) 400× magnification H&E). IgG4 immunohistochemistry highlight plasma cells within fibrotic stroma (400× magnification).

Figure 4.

Magnetic resonance imaging at 18-month mark; enhancing scar at the site of previous lesion depicted by the arrow.