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Clinical Research on Benign Lymphoepithelial Lesions of Lacrimal Gland in 20 Chinese Patients

Background: Benign lymphoepithelial lesion (BLEL) is characterized by symmetric bilateral swelling of the lacrimal and salivary glands and considered a subtype of immunoglobulin G4 (IgG4)-related sclerosing disease, the etiology and pathogenesis of which has not been determined. The purpose of the present study was to analyze the clinical features of BLEL in the lacrimal gland and the relationship between the serum level of IgG4 and BLEL. Methods: Twenty consecutive patients with BLEL diagnosed in Department of Ophthalmology at Beijing Tongren Hospital, Capital Medical University between January 2012 and December 2013 were observed. The clinical features, imaging findings, laboratory tests, treatments and follow-up status of these 20 consecutive patients were analyzed. Results: In all 20 patients, the ratio of male to female was 1:4, the ages ranged from 28 to 57 years, the ratio of unilateral to bilateral eyes involvement was 1:4, and painless uncongested symmetrical swelling of the upper eyelid was the main clinical manifestation. Orbital magnetic resonance imaging (MRI) showed that all patients involved lacrimal gland, which were obviously enlarged with equal signals in T1W images and T2W images and obvious enhancement on contrast MRI. Extraocular muscles were involved in 5 patients, salivary gland in 8 patients, and frontal nerve in 3 patients. Serum IgG4 concentration was elevated in 18 patients. The treatment strategy mainly included surgery and steroid administration. Three patients were lost to follow-up, 17 patients reached complete response, and no recurrence was observed. Conclusions: Eyelid swelling is the typical symptom of BLEL. Most of the patients involved bilateral lacrimal glands. High serum IgG4 level and abundant IgG4-positive plasma cell infiltration are the important features, which can be found in most of BLEL patients. Surgery combined with glucocorticoids is an efficient treatment strategy.


INTRODUCTION
Benign lymphoepithelial lesion (BLEL), also called Mikulicz's disease (MD), is characterized by symmetric bilateral swelling of the lacrimal and salivary glands and considered a subtype of immunoglobulin G4 (IgG4)-related sclerosing disease, the etiology and pathogenesis of which has not been determined. In 1888, Mikulicz reported a patient with bilateral, painless, and symmetrical swelling of the lacrimal, parotid, and submandibular glands, and BLEL was first discovered. [1] Then Mason et al. [2] in 2003 found that the expressions of transforming growth factor-beta (TGF-ß) are different in different tissues, and the decreased expression of its subtype TGF-ß1 in the gland can explain the abundant lymphocyte infi ltration and epithelial cell and lymphocyte proliferation. Therefore, they raised the TGF-ß hypothesis. Ihrler et al. [3] studied the salivary glands in 12 patients with MD and 8 normal individuals. They thought that the development of duct lesions in BLEL arises from basal cell hyperplasia of striated ducts with aberrant differentiation into a multi-layered and reticulated epithelium characterized by profound alteration of the cytokeratin pattern. This functionally inferior, metaplastic epithelium is similar to the lymphoepithelial crypt epithelium of palatine tonsils and the basal cell infi ltration hypothesis. Recently, a novel clinicopathological entity of IgG4-related diseases (IgG4-RD) has recently been proposed, which is characterized by infi ltration of IgG4-positive plasma cells and lymphocytes with fibrosis. Although autoimmune pancreatitis (AIP), one of the organ characteristics of IgG4-RD, has been international reported, there are only a few reports of IgG4-related BLEL. The research on a large case series of BLEL is rare. The purpose of the present study was to clarify the clinical features of 20 patients with BLEL in the lacrimal gland and the relationship between the serum level of IgG4 and BLEL.

Patients and materials
Twenty consecutive patients with BLEL, who were diagnosed between January 2012 and December 2013 by histopathologic examination, were observed. All patients were hospitalized in Department of Ophthalmology at Beijing Tongren Hospital, Capital Medical University. Clinical data of all patients including age, sex, chief complaint, history of present illness, past history, clinical manifestation, and physical examination were analyzed. The research has been approved by the Ethics Committee of Beijing Tongren Hospital and conducted according to the principles in the declaration of Helsinki. Written informed consents have also been obtained from all participants.

Imaging examinations
Imaging examinations mainly included chest X-ray, orbital magnetic resonance imaging (MRI), and upper abdominal computed tomography (CT).

Histology and immunohistochemistry
Surgically resected specimens of lacrimal gland were fi xed in 10% formaldehyde and embedded in paraffi n. Serial sections were cut from each paraffin-embedded tissue block, and several sections were stained with hematoxylineosin staining, and were immunostained for IgG and IgG4-expression cells. Immunostaining for IgG and IgG4 expression was performed using a rabbit monoclonal antibody against human IgG (abcam, ab109489, Hong Kong, China) and IgG4 (abcam, ab109493, Hong Kong, China). The extent of IgG4-positive plasma cell infi ltration was evaluated independently by two pathologists. The degree of infi ltration was scored as negative, mild, moderate or marked according to the number of IgG4-positive plasma cells seen on high-power fi eld (HPF) in each specimen, and the areas with the highest density of IgG4-positive plasma cells were evaluated. For each tissue section, the mean number of IgG4-positive plasma cells was calculated from four examined HPF. Tissue sections were subdivided as follows: Negative ≤10/HPF; mild >10, and ≤30/HPF; moderate >30, and ≤100/HPF; marked >100/HPF.

Treatment and follow-up status
Treatment strategy was total excision combined with postoperative steroid administration, which was used as following: 80-120 mg intravenous methylprednisolone per day for 3 days and then changed to oral methylprednisolone administration with an initial dosage of 0.4 mg·kg −1 ·d −1 , and then tapered slowly based on the response.

General clinical data
In all 20 patients, the male-to-female ratio was 1:4, and the ages ranged from 28 to 57 years with a median age of 45 years. The ratio of unilateral to bilateral eyes involvement was 1:4, and painless uncongested asymptomatic symmetrical swelling of the upper eyelid was the main clinical manifestation and complaint [ Figure 1 and Table 1]. In addition, 3 patients had a history of salivary gland surgery, and 1 patient had a history of hepatitis C.

Imaging findings of sites involved
Orbital MRI showed that all 20 patients involved lacrimal gland, which were obviously enlarged with equal signals in T1WI and T2WI and obvious enhancement on contrast MRI [ Figure 2]. Extraocular muscles were involved in 5 patients, salivary gland in 8 patients and frontal nerve in 3 patients [ Table 4]. Chest X-ray was normal in all patients. Nine patients underwent upper abdominal CT, and only one case was found to have an abnormally thickened gallbladder wall.

Pathological findings
Prominent lymphoplasmacytic infi ltration with lymphoid follicles was observed with the destruction and atrophy of the lacrimal gland lobules and periductal fi brosis [ Figure 3a]. Immunostaining for IgG4 expression showed that numerous IgG4-positive plasma cells infi ltrated the lesion [ Figure 3b].
There were 16 patients of moderate (80%), 2 patients of marked, 1 patient of mild, and 1 patient of negative infi ltration; and the degree of IgG4 expression in both tissue and blood was accordant [ Table 3].

Treatment and follow-up status
Follow-up clinical data were available for 17 patients. The    duration of follow-up ranged from 2 to 20 months. All patients reached a complete response; no recurrence was observed [ Table 1].

DISCUSSION
The patients with BLEL in this study were mainly middle-aged females with a male-to-female ratio of 1:4. The median age was 45 years (range 28-57 years). The enlargement of the lacrimal and (or) salivary glands in patients with BLEL was found to be uncongested and symmetrical as well as asymptomatic and nontender to palpation, which was consistent with the previous literatures. [4] The patients with BLEL might also suffer from other IgG4-RDs, including AIP, retroperitoneal fi brosis, tubulointerstitial nephritis, autoimmune hypophysitis or Riedel's thyroiditis. [5,6] However, none of the patients in our study showed any evidence of these diseases, and only one patient was found to have abnormal thickening of the gallbladder wall on CT. The reason may be associated with age, duration of disease, quantity of patients, and so on. All kinds of imaging examinations lacked specifi c features.    Recently, the phenomenon that patients with BLEL have a high level of serum IgG4 has been discussed more and more, and the concept that BLEL is a subtype of IgG4-related sclerosing disease has been increasingly accepted by doctors and scholars. [7,8] However, the role of IgG4 remains unknown. Our serological analysis revealed that 90% of patients with BLEL had elevated concentrations of IgG4, which has not been observed in any other connective tissue disease, including SS, systemic lupus erythematosus, rheumatoid arthritis, and polymyositis. Therefore, elevated serum IgG4 the concentration is a very specifi c and necessary index in the diagnosis of BLEL.
In addition, we found that the ESR level was elevated in 6 patients (30%), the CRP level was higher in one case (5%), the C3 levels were lower in 9 patients (45%), the C4 levels were lower in 3 patients (15%), the RF levels were higher in 7 patients (35%), and the ASO level was normal in all patients. The fact that hypocomplementemia existed in 45% of patients with BLEL was a very surprising fi nding, which needs more in-depth research to investigate the relationship between BLEL and hypocomplementemia. We suspected that low C3 concentration may be associated with a high IgG4 concentration.
In our study, imaging examinations mainly included chest X-ray, orbital MRI, and upper abdominal CT. Orbital MRI showed that all 20 patients involved lacrimal gland, which were obviously enlarged with equal signal in T1WI and T2WI and obvious contrast enhancement. In addition, extraocular muscles were involved in 5 patients, salivary gland in 8 patients, and frontal nerve in 3 patients, which was seldom reported in the previous studies. However, it was diffi cult to identify the involved sites whether they were primary or just an infl ammatory response, and it needs further pathological examination of surgically resected specimens.
In this study, the lacrimal gland for anti-IgG4 antibody staining, and elevated concentrations of IgG4 were also detected in patients with BLEL. The infi ltration of numerous IgG4-positive plasmacytes near acinar and ductal cells and around lymphoid follicles was confi rmed in BLEL, which was completely consistent with the previous reports. [9][10][11] And, it was also found that the degree of IgG4 expression in both tissue and blood was accordant.
Benign lymphoepithelial lesion refers to idiopathic, bilateral, painless, and symmetrical swelling of the lacrimal, parotids, and submandibular glands. Its diagnosis needs comprehensive considerations and includes clinical manifestations, physical examination, imaging exams, serological exam, and so on. In addition, a differential diagnosis is necessary to distinguish BLEL from other distinct disorders, including sarcoidosis, Castleman's disease, Wegener's granulomatosis, and lymphoma, especially SS. [12] BLEL and SS are histologically similar; therefore, BLEL is considered a subtype of SS. However, BLEL and typical SS differ in some clinical features. Serologically, patients with BLEL lack anti-SS-A and anti-SS-B antibodies. It has also been confi rmed that patients with BLEL show elevated serum IgG4 levels and infi ltration of IgG4-positive plasmacytes in the lacrimal and salivary glands. Thus, BLEL is apparently different from SS. In our research, anti-SS-A and anti-SS-B were examined in all patients, and none of them showed abnormal level.
Benign lymphoepithelial lesion is mainly treated with administration of glucocorticoids, which has satisfied effect. [12] However, in our clinic, all patients had been treated by glucocorticoids administration, and relapsed on a reduced dose of glucocorticoids, so our treatment strategy changed to total excision combined with postoperative steroid administration, which was different from the literatures. In our study, the duration of follow-up was relatively short and ranged from 2 to 20 months. Follow-up clinical data were available for 17 patients (85%). It was so excited that all patients reached a complete response. We will certainly continue our study as long as we can to determine its long-term prognosis. There have also been reports on malignant transformation in BLEL. [13][14][15] However, none of the patients exhibited malignant transformation. Further analysis of complicating lymphoma in BLEL is necessary as there is no evidence on its long-term prognosis.