UNASSIGNED: Hepatic Inflammatory Pseudotumor (IPT) is an infrequent condition often masquerading as a malignant tumor, resulting in misdiagnosis and unnecessary surgical resection. The emerging concept of IgG4-related diseases (IgG4-RD) has gained widespread recognition, encompassing entities like IgG4-related hepatic IPT. Clinically and radiologically, corticosteroids and immunosuppressive therapies have proven effective in managing this condition.
UNASSIGNED: A 3-year-old Chinese boy presented to the clinic with an 11-month history of anemia, fever of unknown origin, and a tender hepatic mass. Blood examinations revealed chronic anemia (Hb: 6.4 g/L, MCV: 68.6 fl, MCH: 19.5 pg, reticulocytes: 1.7%) accompanied by an inflammatory reaction and an elevated serum IgG4 level (1542.2 mg/L). Abdominal contrast-enhanced computed tomography unveiled a 7.6 cm low-density mass in the right lateral lobe, while magnetic resonance imaging demonstrated slight hypointensity on T1-weighted images and slight hyperintensity on T2-weighted images, prompting suspicion of hepatic malignancy. A subsequent liver biopsy revealed a mass characterized by fibrous stroma and dense lymphoplasmacytic infiltration. Immunohistochemical analysis confirmed the presence of IgG4-positive plasma cells, leading to the diagnosis of IgG4-related hepatic IPT. Swift resolution occurred upon initiation of corticosteroid and mycophenolate mofetil therapies.
UNASSIGNED: This study underscores the diagnostic approach to hepatic IPT, utilizing histopathology, immunostaining, imaging, serology, organ involvement, and therapeutic response. Early histological examination plays a pivotal role in clinical guidance, averting misdiagnosis as a liver tumor and unnecessary surgical interventions.

Inflammatory pseudotumor (IPT) is a rare benign mass characterized by infiltration of inflammatory cells and proliferation of fibrous tissues. Consistent with increasing knowledge about IgG4-related disease (RD), it has been implicated in the etiology of hepatic IPT, which is pathologically classified into two categories with respect to the proportion of IgG4-positive plasma cells: fibrohistiocytic- and lymphoplasmacytic-type. A 66-year-old man was admitted for treatment of cholecystocholangitis. Incidentally, abdominal computed tomography (CT) revealed an ambiguous low-density mass within segment 4 (S4) of the liver. Magnetic resonance imaging (MRI) showed the typical images of hepatic IPT within S4. Together with CT and MRI imaging, we suspected hepatic IPT, and had the opportunity to biopsy the S4 lesion during surgery for cholecystitis. Histopathological examination of liver tissue showed diffuse fibrous tissues, dense lymphoplasmacytic infiltration, and obliterative phlebitis with no evidence of malignancy. Despite infiltration of IgG4-positive plasma cells, these histological findings corresponded with fibrohistiocytic-type hepatic IPT. Similarly, in the resected gallbladder, relatively abundant IgG4-positive cells were observed, but not entirely consistent with IgG4-RD criteria. Although IgG4 immunostaining can be useful for the classification of hepatic IPT, the present histological tissues were borderline condition defined by IgG4-RD criteria. This rare case of hepatic IPT suggests a future focus on the borderline histological features of IgG4-RD.

BACKGROUND: Hepatic inflammatory pseudotumor (IPT) is a rare, benign, tumor-like lesion. Because there are no characteristic laboratory markers or radiological features, hepatic IPT is often misdiagnosed as a malignant neoplasm such as hepatocellular carcinoma (HCC).
METHODS: A 68-year-old man with liver dysfunction due to chronic hepatitis C virus infection and alcoholic liver disease presented with hepatic tumors in segments III and VIII. The levels of serum alpha-fetoprotein (AFP) and its Lens culinaris agglutinin-reactive fraction, AFP lectin 3 (AFP-L3), were elevated to 822.8 ng/ml and 75.2%, respectively. The tumor showed contrast enhancement on contrast-enhanced computed tomography and various accumulation on positron emission tomography. Based on these biological and imaging features, HCC was suspected, and we performed laparoscopic partial hepatectomy for these two tumors. Pathological diagnosis revealed that both tumors were hepatic IPTs with no malignant characteristics. After hepatectomy, the serum AFP and AFP-L3 levels decreased to the normal range.
CONCLUSIONS: We report a very rare case of hepatic IPT with elevated serum AFP and AFP-L3, mimicking HCC. Clinicians should include this rare neoplasm in the differential diagnoses of hepatic tumors even when the serum markers for HCC are elevated.

A 61-year-old Chinese male was found to have a lesion in the left liver during a routine body check-up. Laboratory tests revealed no abnormalities except for a rise in C-reactive protein. Computed tomography showed features suggestive of hepatocellular carcinoma. The patient underwent liver IVb segmentectomy and cholecystectomy. Histopathology showed features of hepatic inflammatory pseudotumor. The C-reactive protein decreased to close to normal on postoperative day 9. A patient with hepatic inflammatory pseudotumor who presented with features mimicking hepatocellular carcinoma was reported. A preoperatively raised C-reactive protein was the only hint which suggested that our patient might have had hepatic inflammatory pseudotumor instead of hepatocellular carcinoma.

BACKGROUND: Hepatic inflammatory pseudotumor (IPT) is a rare disease which often mimics a malignant tumor and is therefore often misdiagnosed and surgically resected. Recently, a concept of IgG4-related diseases (IgG4-RD) has been proposed that is becoming widely recognized and includes IgG4-related hepatic IPT. Corticosteroids are widely accepted as the standard treatment.
METHODS: A 72-year-old Japanese man, who had been followed for ten years after surgery and chemotherapy for treatment of hilar and lower bile duct cancers, developed intermittent fever and abdominal pain and visited this hospital. Blood examinations revealed an inflammatory reaction, worsened glucose intolerance, and an increased level of serum IgG4 (137 mg/dL). Computed tomography (CT) revealed a 5 cm-sized mass in hepatic segment 7. Because of his cancer history, not only was a benign mass suspected, but there was also the possibility of a recurrent biliary malignancy. Liver biopsy was performed and the histology met the criteria for IgG4-related IPT. Corticosteroid therapy was initiated and his symptoms quickly resolved. However, two months later, a repeat CT demonstrated that the hepatic mass had been replaced by an abscess. The abscess was initially refractory, despite tapering corticosteroid treatment, controlling diabetes by intensive insulin therapy, administration of antibiotics, and percutaneous abscess drainage. Finally, after six months, the condition resolved.
CONCLUSIONS: The diagnosis of hepatic IPT is sometimes difficult. To differentiate it from a malignant tumor, histological examination is necessary. Although corticosteroids are recognized as the standard therapy, unexpected and critical complications can develop in cases of IgG4-related hepatic IPT.