Hepatic pseudolymphoma: imaging features on dynamic contrast-enhanced MRI and diffusion-weighted imaging

Reactive lymphoid hyperplasia of the liver: A case report featuring characteristic nodular and perinodular enhancement

A 53-year-old female with primary biliary cholangitis was referred for the evaluation of a hepatic nodule identified during routine imaging. Ultrasonography revealed a homogeneous, hypoechoic, 18 mm nodule in segment 3 of the liver. On dynamic CT and MRI, the nodule showed mild enhancement at the hepatic artery-dominant phase. On diffusion-weighted images, the nodule exhibited pronounced hyperintensity with accompanying wedge-shaped perinodular hyperintensity (comet and comet-tail appearance). The nodule showed a portal perfusion defect on CT during arterial portography, and mild enhancement on CT during hepatic arteriography (CTHA). A nodular and wedge-shaped perinodular enhancement (comet and comet-tail appearance) in the CTHA was also clearly observed. The nodule demonstrated abnormal FDG uptake on 18F-FDG-PET/CT. An excisional biopsy was performed for histopathological diagnosis, and the nodule was diagnosed as reactive lymphoid hyperplasia (RLH). Diagnosing hepatic RLH by imaging is challenging due to its imaging findings overlapping with those of various malignant tumors, especially the nodular type of lymphomas, making differentiation particularly difficult. However, radiologists should note the perinodular early enhancement and the perinodular hyperintensity on diffusion weighted images, which are thought to be key imaging findings of RLH, along with other characteristics such as a single, small, homogeneous nodule with mild early enhancement and marked restricted diffusion. We propose to name the nodular lesion with perinodular early enhancement/hyperintensity on diffusion weighted images as 'comet and comet-tail appearances'.

Reactive lymphoid hyperplasia of the liver: A rare case report

BACKGROUND

Hepatic reactive lymphoid hyperplasia (RLH) is a rare benign lymphoproliferative lesion and a poorly understood disease. It is usually asymptomatic and incidental, but it is difficult to distinguish from hepatocellular carcinoma and metastatic liver tumor on imaging, and percutaneous biopsy is not sufficient to distinguish from low-grade malignant lymphoma and extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT lymphoma), making diagnosis difficult.

CASE SUMMARY

A 69-year-old woman came to our hospital for reexamination of pulmonary nodules followed by liver occupation. The lesions showed "wash-in and wash-out" on contrast-enhanced ultrasonography and magnetic resonance imaging. Enhanced magnetic resonance also showed annular envelope enhancement and limited diffusion on the ADC map during the delay period. Imaging revealed metastatic liver cancer, and the patient underwent a partial hepatectomy. However, the final histopathological diagnosis was RLH.

CONCLUSION

If small isolated nodules are found in the liver of middle-aged and elderly female patients with no risk factors for liver malignancy, when the enhanced imaging suggests "wash-in and wash-out", further focus should be placed on whether the enhanced imaging shows perinodular enhancement and whether the DWI shows limited diffusion in MRI, in order to emphasize the possibility of liver RLH diagnosis.

A case of difficult-to-diagnose hepatic reactive lymphoid hyperplasia finally diagnosed by using PCR analysis of IgH-gene rearrangements: a case report

Reactive lymphoid hyperplasia (RLH) of the liver is extremely rare. Despite advancements in diagnostic imaging technology, it is still difficult to distinguish from hepatocellular carcinoma (HCC). Herein, we present a case of hepatic RLH mimicking HCC that was postoperatively diagnosed using several imaging modalities. A 78-year-old female was referred to our hospital with a positive hepatitis C virus antibody (HCV Ab) test. Ultrasonography revealed a 13 mm isoechoic lesion in segment 8 of the liver. Contrast-enhanced computed tomography (CE-CT) demonstrated arterial hyperintensity and washout during the later phase. On ethoxybenzyl magnetic resonance imaging (EOB-MRI), the lesion was hyperenhanced in the arterial phase and of low intensity in the hepatocyte phase. Although the tumor markers were all within normal limits, the pattern of contrast enhancement of the tumor on CT and MRI was consistent with that of HCC. We performed S8 segmentectomy of the liver. Histological examination of the resected specimen revealed dense lymphoid tissue of variable sizes and shapes with expanded germinal centers. Immunohistochemical examination was positive for CD3, CD10 (germinal center), and CD20, and negative for B-cell lymphoma 2 (bcl-2) (germinal center) and Epstein-Barr virus (EBV). A polymerase chain reaction (PCR) analysis of IgH-gene rearrangements revealed polyclonality. Based on these findings, hepatic RLH was diagnosed. The postoperative course was uneventful, and the patient was discharged on the 10th postoperative day. She had a good quality of life after surgery and no liver nodule recurrence was detected at the 4-month medical follow-up. Hepatic RLH is an extremely rare disease and preoperative diagnosis is difficult. This should be considered in the differential diagnosis of single small hepatic tumors. An echo-guided biopsy and careful observation of imaging may help diagnose hepatic RLH, and a PCR analysis of IgH-gene rearrangements would be necessary for the definitive diagnosis of hepatic RLH.

Hepatic reactive lymphoid hyperplasia-associated primary biliary cholangitis masquerading as a neoplastic liver lesion

Hepatic reactive lymphoid hyperplasia is an uncommon benign condition, often found incidentally as a solitary liver lesion. The chronic inflammatory reaction associated with autoimmune conditions and malignancies has been postulated as a possible aetiology. The diagnosis is challenging as it often mimics various malignancies radiologically and histologically, hence the diagnosis being made only after surgical resection. Lymphadenopathy is common with primary biliary cholangitis, though rarely reported with reactive lymphoid hyperplasia. We report a case of hepatic reactive lymphoid hyperplasia associated with portacaval lymphadenopathy in a patient with primary biliary cholangitis, diagnosed after surgical resection. We propose lesional biopsy be considered in patients with primary biliary cholangitis found to have a solitary lesion with supporting low-risk clinical and radiological features.

Liver pseudolymphoma (reactive lymphoid hyperplasia): Difficulty in radiological and pathological diagnosis

Pseudolymphoma of the liver (reactive lymphoid hyperplasia) (RLH) is a rare condition. It is usually asymptomatic and detected incidentally on radiological imaging. Imaging features are similar to hepatic adenoma, hepatocellular carcinoma, cholangiocarcinoma, and malignant lymphoma and are not specific for pseudolymphoma of the liver. Percutaneous core biopsy is insufficient to distinguish pseudolymphoma of the liver from low-grade malignant lymphoma and extranodal marginal lymphomas. In this article, we present a case of hepatic RLH of a patient who presented with a skin rash on the leg and was detected incidentally on radiological imaging.

Diffusion-weighted imaging might be useful for reactive lymphoid hyperplasia diagnosis of the liver: A case report

BACKGROUND

Reactive lymphoid hyperplasia (RLH) of the liver is a rare liver lesion. It is considered difficult to differentiate radiologically from hepatocellular carcinoma, metastatic liver tumor and other pathologies.

CASE SUMMARY

A 54-year-old woman presented to our hospital with RLH of the liver. The patient had a diagnosis of metastatic carcinoma of the liver from an unknown origin and subsequently underwent partial hepatectomy. However, histopathological analysis revealed RLH. The lesion showed perinodular enhancement in the arterial phase on contrast-enhanced computed tomography and magnetic resonance imaging. On diffusion-weighted imaging (DWI), we encountered linear hyperintensity along the portal tract consecutive to the liver lesion, which is a new characteristic radiologic finding. This finding corresponded to the lymphoid cell infiltration of the portal tract. Furthermore, there was strongly restricted diffusion on the apparent diffusion coefficient map. We used these characteristic radiologic findings to diagnose the lesion as a lymphoproliferative disease.

CONCLUSION

The linear hyperintensity consecutive to the liver lesion on DWI provided additional valuable diagnostic information.

A case of reactive lymphoid hyperplasia of the liver in a patient with autoimmune hepatitis

Background

Reactive lymphoid hyperplasia (RLH) of the liver is a benign disorder. It is usually observed in the skin, orbit, thyroid, lung, breast, or gastrointestinal tract, but rarely in the liver. Since the first report of RLH of the liver in 1981, only 75 cases have been described in the past literature. Herein, we report a case of RLH of the liver in a patient with autoimmune hepatitis (AIH), which was misdiagnosed as hepatocellular carcinoma (HCC) preoperatively and resected laparoscopically.

Case presentation

A 43-year-old Japanese woman with autoimmune hepatitis was followed up for 5 years. During her medical checkup, a hypoechoic nodule in segment 6 of the liver was detected. The nodule had been gradually increasing in size for 4 years. Abdominal ultrasound (US) revealed a round, hypoechoic nodule, 12 mm in diameter. Contrast-enhanced computed tomography (CT) demonstrated that the nodule was slightly enhanced in the arterial dominant phase, followed by perinodular enhancement in the portal and late phases. A magnetic resonance imaging (MRI) scan showed low signal intensity on the T1-weighted image (T1WI) and slightly high signal intensity on the T2-weighted image (T2WI). The findings of the Gd-EOB-DTPA-enhanced MRI were similar to those of contrast-enhanced CT. Tumor markers were all within the normal range. The preoperative diagnosis was HCC and a laparoscopic right posterior sectionectomy was performed. Pathological examination revealed that the nodular lesion was infiltrated by small lymphocytes and plasma cells, and germinal centers were present. Immunohistochemistry was positive for B cell and T cell markers, indicating polyclonality. The final diagnosis was RLH of the liver.

Conclusions

The pathogenesis of RLH of the liver remains unknown, and a definitive diagnosis based on imaging findings is extremely difficult. If a small, solitary nodule is found in female patients with AIH, the possibility of RLH of the liver should be considered.

Diagnosis and treatment of hepatic pseudolymphoma

Pseudolymphoma, also known as reactive lymphoid hyperplasia or nodular lymphoid lesion, can occur in the gastrointestinal tract, pancreas, eyelids, skin, etc.; however, pseudolymphoma of the liver rarely occurs. Because of the small number of individual case reports of hepatic pseudolymphoma in most institutions, there is a lack of information available regarding its pathogenesis, optimal treatment, and prognosis. Patients with hepatic pseudolymphoma often present non-specific clinical and imaging features, without specific tumor markers. The diagnosis of this disease mainly depends on postoperative pathological and immunohistochemical evaluations and genetic examination; timely and complete surgical resection is currently the most important treatment.