A Case of Hypereosinophilia-Associated Multiple Mass Lesions of Liver Showing Non-Granulomatous Eosinophilic Hepatic Necrosis

Hypereosinophilic syndrome (HES) is defined by elevation more than 1.5×109/L of presence of a peripheral blood count, evidence of organ involvement, and exclusion of secondary eosinophilia such as allergic, vasculitis, drugs, or parasite infection and also clonal eosinophilia. We present the HES case with hepatic involvement. The patient is 70-year-old male. He complained fever and back pain. Blood examination showed marked peripheral eosinophilia, elevation of transaminase and biliary enzymes. Multiple irregular mass lesions of the liver were pointed out by CT and MRI. The liver biopsy was done for differentiation from malignancy. In parenchyma, hepatic necrotic lesion was observed accompanying severe eosinophilic infiltration with Charcot-Leyden’s crystals. There was granulomatous reaction. He was diagnosed as HES and got recovery due to steroid therapy. From the review of HES article, the hepatic histology is categorized into four types as below: 1) cholangitis type; 2) chronic active hepatitis type; 3) vasculopathic type, 4) hepatic necrosis type. Our case is classified in hepatic necrosis type. This type seems to be important to distinguish malignant tumor and also visceral larva migrans by liver biopsy.


Introduction
Prominent eosinophilic infi ltration of the liver is commonly seen in visceral larva migrans histologically presenting palisading granuloma [1,2]. Occasional eosinophilic infi ltration to some degree is known in drug-induced hypersensitivity as well as primary sclerosing cholangitis (PSC) [3], primary biliary cirrhosis (PBC) [4]. Hypereosinophilic syndrome (HES) is indispensable disease related to eosinophilic hepatic necrosis, although it is rare.
Hypereosinophilic syndrome is thought to be a heterogeneous group of disorders characterized by peripheral eosinophilia and involvement of various organs. The diagnosis needs exclusion of other specifi c causes for eosinophilia such as infectious disease (parasitosis), autoimmune diseases (Churg-Strauss syndrome, Wegener granulomatosis), allergic infl ammation to specifi c antigen, and neoplastic hematopoietic disorders [5]. Hepatic involvement of hypereosinophilic syndrome is uncommon, however, has been suggested to associate with the various type of liver injury. For example, cholangitis [6], chronic active hepatitis (CAH) [7], Budd-Chiari syndrome [8], and nodular regenerative hyperplasia (NRH) [9] has been reported in the patients of hypereosinophilic syndrome.
Herein, we present the case of hypereosinophilia with hepatic eosinophilic necrosis in liver histology and multiple liver mass lesions on radiological fi ndings, which was diffi cult to differentiate from malignancy.

Case Report
A 70-year-old Japanese male complained fever and back pain. He was pointed out liver injury on blood examination. Imaging studies revealed multiple space-occupying lesion (SOL) of the liver. He was admitted for the examination of liver SOL. He has no familial history, no medication, no any allergy, animal pet, and habits of eating raw meat. In past history, he suffered cholecystlithiasis several years ago. Laboratory data at admission is shown in Table 1. The counts of white blood cell (WBC) elevated, particularly eosinophil increased markedly up to 62% (13200/μl). IgE RIST was high level and eosinophil cationic protein (ECP) was mildly elevated, which implied allergic or other infl ammatory reaction with involvement of the eosiophil in the process Manuscript accepted for publication July 19, 2011 [10]. The serologic test for Toxocara species was negative. Transaminase and biliary enzyme were moderately increased. Noticeable elevation of tumor markers was nothing, except for soluble interluekin-2 receptor (sIL-2R).
Radiological fi nding showed multiple mass lesions of the liver (Fig. 1). Those lesions were low density on abdominal CT, which were not enhanced. MRI image showed low-intensity on T1-weight and iso-intensity on T2-weight. Metastatic tumor, cholangiocarcinoma, malignant lymphoma, and infl ammatory pseudotumor were candidates as dif- ALT, alanine aminotransferase; ALP, alkaline phosphatase; AST, aspartate aminotransferase; BUN, blood urea nitrogen; CA19-9, Carbohydrate antigen 19-9; CRP, C-reactive protein; ECP, Eosinophil cationic protein; γ-GTP, gamma-glutamyl transpeptidase; HBsAg; hepatitis B surface antibody, HCV-Ab; hepatitis C virus antibody, IgE, immunoglobulin E; IL-4, interleukin-4; IL-5, interleukin-5; IL-6, interleukin-6; LDH, lactate dehydrogenase; PIVKA-II, protein induced by vitamin K absence or antagonist-II; Plt, platelet; RBC, red blood cell; sIL-2R, soluble interleukin-2 receptor; WBC, white blood cell. ferential diagnosis. Bilateral pleural effusion was pointed out in extrahepatic organ. After admission, he complained asthma-like symptom and pleural fl uid was detected by chest CT. The liver biopsy was performed for diagnosis of the mass lesions. Liver needle biopsy revealed multifocal eosinophile's infi ltrative lesion in portal tracts and hepatic parenchyma (Fig. 2a, b). Cellular atypia of eosinophile was not distinct. The majority of infi ltrative cells were eosinophil in parenchyma, whereas lymphocytes were mixed to some degree in portal tracts. The lymphocytes showed small round nuclei without atypia, and polyclonal on immunohistological fi ndings. The granulomatous reaction was not observed at all. The fragments of necrotic tissue were seen here and there, and a lot of Charcot-Leyden's crystals were found in the necrotic area (Fig. 2c, d).
The steroid pulse therapy was undergone after liver biopsy. The count of eosinophile in peripheral blood fell down rapidly within normal range after steroid therapy. The hepatic masses became gradually reduced and disappeared in about half a year. He has been followed for 5 years and no recurrence.

Discussion
Eosinophilia is generally categorized into clonal, secondary, and idiopathic types. Clonal eosinophilia is diagnosed by the presence of histologic, cytogenetic, or molecular evidence of an underlining myeloid malignancy. Actually, a lot of examination including the assessment of peripheral blood smear, bone marrow morphologic features, cytogenetic analysis, mutation analysis of specifi c gene, lymphocyte phenotyping, and T-cell receptor gene rearrangement are needed to rule out the clonal eosinophilia [11]. Our case is unlikely clonal type because of rapid improvement against steroid therapy, before vigorous examination. Secondary eosinophilia is caused by parasite infection, allergic, systemic vasculitis, drugs, and nonmyeloid malignancy. In our case, parasite infection, particularly visceral larva migrans, had to be differentiated because hepatic involvement with eosinophilia and multiple lesion on imaging is frequently observed. To our knowledge, the characteristic histological fi nding of parasitic infection is eosinophilic granuloma in almost cases, except one case of hydatid disease showing eosinophilic cholangitis [1,2,[12][13][14]. It seemed that the possibility of visceral larva migrans could be denied because the granulomatous reaction was not found at all in liver biopsy, and antihelminthic treatment was not needed in our patient. Specifi c factor determining cause of eosinophilia didn't detected over fi ve years, although it seems to be diffi cult complete exclusion of secondary eosinophilia.
HES is a subcategory of idiopathic type, and defi ned by the presence of a peripheral blood eosinophil count of 1.5 × 10 9 /L or greater for at least 6 months, exclusion of both clonal and secondary eosinophilia, evidence of organ involvement, like as Chusid et al. proposed in 1975 [11, 15]. This   case didn't fi ll strictly above criteria, however, he was good responder of corticosteroid therapy, which is the fi rst-line therapy for HES [5]. A shorter duration by the proper therapy has been allowed for diagnosis for HES [11], therefore, this case likely to be HES. Liver involvement of the HES does occur in the frequency of 43% [16]. We review the cases reported as HES, which hepatic histology has been evaluated by liver biopsy in Table  2. The variety of histological fi ndings seems refl ect the heterogeneity of HES. The hepatic histology of HES is classifi ed into four types: 1) cholangitis type; 2) chronic active hepatitis (CAH) type; 3) vasculopathic type; 4) hepatic necrosis type. Prominent eosinophilic infi ltration to portal tracts, bile ducts, venous system, or hepatic parenchyma were observed in each type. The characteristics and differential diagnosis are raised in each group. 1), Cholangitis type (case No. 1 -5). All patients were man and icteric. The discrimination form PSC were discussed quite often, because similarity of radiological or histological fi ndings, and also complication of eosinophilic colitis, which is consistent with infl ammatory bowel disease. 2), CAH type (case No. 6 -9). Non-specifi c radiological fi nding, portal fi brosis with interface eosinophilic hepatitis in histology, and practicable disease control by steroid therapy are characteristics in this groups. PBC, as well as autoimmune hepatitis (AIH) should be excluded by careful clinical follow up and repeated histological examination, because actually AMA-positive, or ANA-positive patient was reported [21,22]. 3), Vasculopathic type (case No. 10,11). Case 11 with Budd-Chiari syndrome and FIP1L1-PDGFRA fusion gene is currently categorized into myeloid and lymphoid neoplasm with eosinophilia and abnormalities of platelet derived growth factor receptor α (PDGFRA), PDGFRB or fi ibroblast growth factor receptor (FGFR1) in the revised 2008 WHO classifi cation system, and defi nitely excluded from HES [24]. No abnormalities were detected in chromosomal analysis including Philadelphia chomosome in NRH patients (case No. 10) at the point, but the patients had persisted liver injury over two years despite of steroid, and also hydroxyurea, and thioguanine [9]. Vigorous examination of specifi c fusion gene and chromosomal abnormalities might be needed whenever encounter the vasculopathic type considering the possibility of neoplastic disease. 4), Hepatic necrosis type (case No. 12, 13). The notable characteristics of this group is hepatic multiple mass lesion pointed out on radiologists, which are diffi cult to distinguish from malignancy, such as cholangiocellular carcinoma, metastatic carcinoma, or malignant lymphoma [25][26][27]. Needle biopsy seems essential to exclude above malignancy and also visceral larva migrans, which leads to avoid inappropriate surgery or medication. The patients, just two in reports, both immediately improved against steroid therapy in clinical and radiological fi ndings, which seems to suggest that the group has unlikely neoplastic nature. Drug intake should always remind whenever eosinophilic infi ltration is seen in liver, if any pattern.
We presented in this article the case of hepatic eosinophilic necrosis showed liver mass lesions and reviewed the liver histology of HES. In conclusion, the histology is categorized four types: cholangitis type, CAH type, vasculopathic type, and hepatic necrosis type. PSC, PBC, AIH, neoplastic eosinophilia, parasitic infection, malignancy, and drug can be differential disease in each type. It is important that HES is one of the mass forming disease in liver, and liver biopsy is useful to exclude differential disease for steroid therapy.