Reactive lymphoid hyperplasia of the liver and pancreas. A report of two cases and a comprehensive review of the literature

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.

A case of hepatic reactive lymphoid hyperplasia: the review of 23 cases from the literatures

A 70-year-old woman was referred to our hospital because of slight elevation of soluble interleukin-2 receptor (sIL-2R) and accumulation of 18F-fluorodeoxyglucose (FDG) in S8 of the liver on positron emission tomography. The mass was strongly suspected to be malignant because of contrast enhancement and enlargement in size of the mass, and suspicion of portal vein invasion. Hepatic S8 subsegmentectomy was performed for diagnostic and therapeutic purposes. Hematoxylin and eosin staining of the resected specimen showed small lymphocytes with no atypia and no formation of lymphoid follicles. Immunostaining showed CD3-positive cells in the interfollicular region and CD20-positive cells in the lymphoid follicles. Both CD10 and BCL-2 were negative in the follicular germinal center. CD138-positive plasma cells were observed and there was no light chain restriction. Based on polyclonal growth pattern of lymphocytes in the lymphoid follicles and interfollicular region, she was diagnosed with hepatic reactive lymphoid hyperplasia (RLH).Review of the English literature of hepatic RLH which referred to imaging findings yielded 23 cases, including this case. As a result, we suggest that liver biopsy should be performed for definitive diagnosis, when hepatic RLH is suspected by imaging findings and backgrounds.

Clinical features, natural history and outcomes of pseudolymphoma of liver: A case-series and systematic review

BACKGROUND

Pseudolymphoma is a rare, benign, nonspecific condition that forms a mass-like lesion characterized by the proliferation of non-neoplastic lymphocytes. Lacking of specific clinical symptoms, serological markers, and imaging features, the diagnosis is difficult. We reporte five cases of hepatic pseudolymphoma and provide a systematic review of existing literatures to improve our understanding of this rare liver disease.

METHODS

We followed-up five cases of hepatic pseudolymphoma in West China Hospital from January 2002 to January 2022. We also summarized the cases of hepatic pseudolymphoma from January 1981 to December 2021 through the PubMed database and comprehensively analyzed the characteristics of the cases.

RESULTS

The pathologic features of the five cases were characterized by benign lymphoid tissue hyperplasia, lymphoid follicle formation, and a polarized germinal center. Immunohistochemistry, in situ hybridization, and gene rearrangement revealed non-malignant lymphoma. Besides, a total of 116 cases have been reported in the PubMed database from 1981 to 2021. The incidence of hepatic pseudolymphoma is higher in middle-aged and elderly women and has been reported more frequently in Asia. All cases were pathologically diagnosed, among which 85.95% of the patients were treated by surgery.

CONCLUSIONS

Hepatic pseudolymphoma is an extremely rare benign disease, mainly in middle-aged and elderly women. Without distinctive clinical and imaging characteristics, pathological diagnosis is the highly reliable method at present. Thus, in the absence of risk factors for a primary liver tumor or metastatic tumor in middle-aged and elderly women, the possibility of pseudolymphoma should be considered to avoid extensive treatments.

OUP accepted manuscript

Reactive lymphoid hyperplasia (RLH) of the liver is an extremely rare benign lesion, which is often misdiagnosed as a malignant liver tumour. We present the case of a 69-year-old man with an incidental liver tumour revealed on the ultrasonography of the kidney-urinary bladder system for benign prostatic hyperplasia. Hepatocyte-specific contrast (gadoxetate disodium) magnetic resonance imaging revealed a round 6-mm lesion, which was hypointense on T1-weighted images, slightly hyperintense on T2-weighted images and highly intense on diffusion-weighted images. Other findings included arterial hyperintensity, venous and delayed hypointensity and a defect in liver segment 6. The patient was diagnosed with hepatocellular carcinoma; laparoscopic partial hepatectomy was performed. Intraoperatively, a 7-mm greyish white solid nodule was observed. In conclusion, it may be difficult to distinguish RLH from other malignant liver tumours. However, it should be considered as a differential diagnosis for small liver lesions in young, female patients without liver cirrhosis.

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.

Follicular pancreatitis: A rare pancreatic inflammatory pseudotumor

Inflammatory pseudotumors imitate neoplasms on imaging but actually represent focal inflammation. We report a case of follicular pancreatitis, which is a recently recognized distinct form of mass-forming focal chronic pancreatitis pathologically characterized by lymphoid infiltration with abundant reactive germinal centers. In our patient, follicular pancreatitis manifested as a pancreatic tail mass that was resected due to imaging findings, which were suggestive of pancreatic malignancy. We performed a literature review of this rare condition and present a summary of reported imaging findings. The most distinguishing feature from pancreatic adenocarcinoma is the enhancement pattern, as follicular pancreatitis enhances more than the surrounding pancreatic parenchyma on delayed post-contrast images which is unusual for pancreatic adenocarcinoma. If this benign diagnosis is suggested on imaging, unnecessary surgery and its potential complications may be avoided.

Follicular lymphoid hyperplasia of the posterior maxillary site presenting as uncommon entity: a case report and review of the literature

BACKGROUND

Follicular lymphoid hyperplasia (FLH) is characterized by an increased number and size of lymphoid follicles. In some cases, the etiology of FLH is unclear. FLH in the oral and maxillofacial region is an uncommon benign entity which may resemble malignant lymphoma clinically and histologically.

CASE PRESENTATION

We report the case of a 51-year-old woman who presented with an asymptomatic firm mass in the left posterior maxillary site. Computed tomography scan of her head and neck showed a clear circumscribed solid mass measuring 28 × 23 mm in size. There was no evidence of bone involvement. Incisional biopsy demonstrated benign lymphoid tissue. The patient underwent complete surgical resection. Histologically, the resected specimen showed scattered lymphoid follicles with germinal centers and predominant small lymphocytes in the interfollicular areas. Immunohistochemically, the lymphoid follicles were positive for CD20, CD79a, CD10, CD21, and Bcl6. The germinal centers were negative for Bcl2. Based on these findings, a diagnosis of benign FLH was made. There was no recurrence at 1 year postoperatively.

CONCLUSIONS

We diagnosed an extremely rare case of FLH arising from an unusual site and whose onset of entity is unknown. Careful clinical and histopathological evaluations are essential in making a differential diagnosis from a neoplastic lymphoid proliferation with a nodular growth pattern.

Contrast-Enhanced Ultrasound Features of Hepatic Reactive Lymphoid Hyperplasia: Correlation With Histopathologic Findings

OBJECTIVES

To find certain specifics of hepatic reactive lymphoid hyperplasia (HRLH) on contrast-enhanced ultrasound (CEUS) imaging as diagnostic imaging clues by retrospectively analyzing its enhancement features.

METHODS

From June 2010 to June 2017, 18 histopathologically confirmed HRLH lesions in 18 patients were included in this retrospective study. The lesion's location, maximum diameter, shape, margin, echogenicity, and color flow signal on conventional ultrasound (US) imaging and enhancement pattern, presence of a feeding artery, and donutlike enhancement on CEUS imaging were observed and recorded. The lesion size on CEUS imaging at peak enhancement and that on conventional US imaging were compared and recorded.

RESULTS

All of the lesions showed homogeneous hypoechogenicity with a regular well-defined margin on conventional US imaging, with a mean diameter ± SD of 14.3 ± 4.6 mm (range, 8-24 mm). On CEUS imaging, all of the lesions showed "quick-wash-in and quick-wash-out," which showed complete homogeneous hyperenhancement in the arterial phase and wash-out in the second half of the arterial phase or first half of the portal phase. In 83.3% (15 of 18) of the lesions, the lesion size that was enhanced at peak was enlarged compared with the hypoechoic area on conventional US imaging, and transient donutlike enhancement appeared when the lesion showed wash-out. In 55.6% (10 of 18) of cases, the feeding artery was detected.

CONCLUSIONS

Enlarged complete homogeneous hyperenhancement in the arterial phase, consequently followed by quick wash-out of the lesion and the appearance of donutlike enhancement, may be the CEUS features of HRLH.

Intrahepatic Reactive Lymphoid Hyperplasia: A Case Report and Review of the Literature

Introduction

Reactive lymphoid hyperplasia (RLH) is a rare and benign lesion found in organs of the gastrointestinal tract, skin, lung, orbit, and more rarely in the liver. Due to its similar appearance on imaging, it is hard to differentiate from primary liver malignancies. The following is a case report of a patient presenting with a suspicious liver lesion found to be RLH associated with primary biliary cirrhosis (PBC), after surgical resection.

Presentation of Case

A 54-year-old woman presented with nonspecific abdominal pain, and her workup included axial imaging of the abdomen that showed a suspicious lesion in her liver. After an extensive workup, which included a percutaneous biopsy, failed to confirm a diagnosis, a laparoscopic surgical resection was recommended.

Discussion

RLH is a rare condition of the liver, presenting in a suspicious fashion and raising concerns for a primary liver malignancy. RLH should be considered in the differential diagnosis of small hepatic lesions in middle-age females in the absence of any significant risk factors for hepatocellular carcinoma (HCC). RLH tends to be associated with PBC of the liver.

Conclusion

RLH of the liver is a rare, hard to diagnose, benign lesion. When intrahepatic, it cannot be easily differentiated from primary liver tumors and frequently requires surgical resection for pathological diagnostic confirmation.

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

PURPOSE

To investigate dynamic contrast-enhanced (DCE) MR findings and diffusion-weighted imaging (DWI) characteristics of hepatic pseudolymphoma.

MATERIALS AND METHODS

The MR data of 20 lesions in 14 patients with histopathologically proven hepatic pseudolymphoma were retrospectively analyzed. All patients underwent dynamic gadopentetate dimeglumine-enhanced MR imaging and DWI. Morphologic characteristics and signal features on T1- and T2-weighted images (T1WI, T2WI), and DCE pattern were qualitatively evaluated. The quantitative analysis was performed for the size, the degree of enhancement on arterial phase, signal intensity (SI) of DWI, and apparent diffusion coefficient (ADC) values. The Wilcoxon signed ranks test was used for statistical analysis.

RESULTS

The contour of all lesions was round. The lesion size was 0.7-2.8 cm (mean 1.3 ± 0.5 cm). All lesions manifested as homogeneous hypointensity on T1WI and hyperintensity on T2WI. All lesions were shown as hypervascular with various enhancement patterns on DCE MR imaging. The presence of peripheral enhancement and pseudocapsule was observed in 7 and 4 lesions, respectively. SI of the hepatic pseudolymphoma was significantly lower than that of portal vein on arterial phase (P < 0.001) and the ADC was significantly lower than that of spleen (P = 0.012).

CONCLUSION

A homogeneous nodule with small size (<2 cm), manifestation of hypervascular with lower SI than that of portal vein on arterial phase and lower ADC values than that of spleen are the common MR features of hepatic pseudolymphoma.

Hepatic Pseudolymphoma with an Occult Hepatitis B Virus Infection

A 49-year-old woman who was asymptomatic was found to have a small liver tumor on abdominal ultrasonography (US) at her annual health checkup. US revealed a hypoechoic, solid, mass measuring 17-mm in size in segment 6. The tumor markers associated with liver malignancy were negative. An infectious disease screen was negative for hepatitis B surface antigen, but positive for antibody to hepatitis B core antigen. Imaging studies using computed tomography (CT), magnetic resonance imaging (MRI), and CT angiography suggested a malignant liver tumor, such as hepatocellular carcinoma. Partial hepatic resection of the posterior segment was performed. The pathological diagnosis was pseudolymphoma of the liver.

Pseudolymphoma (reactive lymphoid hyperplasia) of the liver: A clinical challenge

Reactive lymphoid hyperplasia (RLH), also known as pseudolymphoma or nodular lymphoid lesion of the liver is an extremely rare condition, and only 51 hepatic RLH cases have been described in the literature since the first case was described in 1981. The majority of these cases were asymptomatic and incidentally found through radiological imaging. The precise etiology of hepatic RLH is still unknown, but relative high prevalence of autoimmune disorder in these cases suggests an immune-based liver disorder. Imaging features of hepatic RLH often suggest malignant lesions such as hepatocellular carcinoma and cholangiocarcinoma. In this report, we discuss two cases of hepatic RLH in patients with autoimmune hepatitis. We also present pathologic and magnetic resonance imaging findings, including one case utilizing a hepatocellular contrast agent, Eovist. Definitive diagnosis of hepatic RLH often requires surgical excision.

Pseudolymphoma of the liver: a case report and literature review

Pseudolymphoma is a benign lymphocytic tumor-like lesion, and its occurrence in the liver is rare. Here, we report the case of a 78-year-old woman with pseudolymphoma of the liver. She had a history of tremors for several years. Therefore, she underwent computed tomography (CT) for screening, and liver tumors were incidentally identified. She did not have any history of liver disease. Liver function test results and tumor marker levels were all within normal limits, and viral markers for hepatitis were negative. Contrast-enhanced CT revealed four nodules measuring up to 13 mm in diameter with ring enhancement in both lobes of the liver. On magnetic resonance imaging, the lesions showed slightly high intensity on T2-weighted images and high intensity on diffusion-weighted images. Because of atypical imaging findings, the tumors could not be definitively diagnosed. Therefore, we performed laparoscopic limited resection of segments 2, 3, 4, and 8 of the liver. The final pathological diagnosis was pseudolymphoma of the liver. The patient has had no signs of recurrence for 6 months after the surgery. Although pseudolymphoma of the liver is rare, it is necessary to consider it in the differential diagnosis of a liver tumor.

Hepatic pseudolymphoma: imaging-pathologic correlation with special reference to hemodynamic analysis

OBJECTIVES

To clarify radiological findings and hemodynamic characteristics of hepatic pseudolymphoma, as compared with the histopathological findings.

METHODS

Radiological findings of ten histopathologically confirmed hepatic pseudolymphomas in seven patients were examined using US, CT, and MRI. Six patients also underwent angiography-assisted CT, including CT during arterial portography (CTAP) and CT during hepatic arteriography (CTHA) to analyze hemodynamics.

RESULTS

The nodules were depicted as hypoechoic on US, hypodense on precontrast CT, hypointense on T1-weighted images, and hyperintense on T2-weighted images. On contrast-enhanced CT/MRI, they showed various degrees of enhancement, and sometimes, perinodular enhancement was observed at the arterial dominant and/or equilibrium phase. On CTAP, the nodules showed portal perfusion defects, including some in the perinodular liver parenchyma. On CTHA, irregular bordered enhancement was observed in perinodular liver parenchyma on early phase, and continued until delayed phase. Some nodules had preserved intra-tumoral portal tracts. Histopathologically, the nodules consisted of marked lymphoid cells. In perinodular liver parenchyma, stenosis or disappearance of portal venules, caused by lymphoid cell infiltration in the portal tracts, was observed.

CONCLUSIONS

Hepatic pseudolymphoma showed some characteristic radiological findings including hemodynamics on CT, MRI, and angiography-assisted CT. These findings are useful in the differentiation from hepatocellular carcinoma and other tumors.