Descriptive epidemiology of ophthalmic and ocular adnexal non-Hodgkin's lymphoma

Mucosal associated Lymphoid Tissue Lymphoma of the uvea: an analysis of 3 cases

Background

Ocular mucosa-associated lymphoid tissue (MALT) lymphoma involving orbit and conjunctiva usually has an indolent clinical course with “salmon patch” mass as typical presentation. This study is to report a series of rare cases and investigate the clinical and pathological features of ocular MALT lymphoma that involved uveal tissue primarily and presented as posterior scleritis.

Methods

This retrospective, observational study was conducted at Beijing Tongren Hospital. From 2018 to 2020, 3 cases of 3 eyes (2 female patients and 1 male patient) with ocular MALT lymphoma that involved uveal tissue primarily and presented as posterior scleritis were included in the study. All patients had complaints of red eyes with blurred vision. The average age was 56.33 ± 2.08 years old and the average time from initial diagnosis to pathological diagnosis was 3.00 ± 1.73 months. Ophthalmic examinations including best-corrected visual acuity (BCVA), intraocular pressure (IOP), slit lamp microscope examinations, fundus photography, B-scan ultrasonography, ultrasound biomicroscope (UBM), optical coherence tomography (OCT), fundus fluorescein angiography (FFA) and indocyanine green angiography (ICGA) were conducted. Systemic workups including orbital magnetic resonance imaging (MRI), positron emission tomography-computed tomography (PET-CT) and blood autoimmune antibody tests were also conducted. Pathological tissue from patients were obtained through surgeries. Biopsy examinations were performed to accurately determine pathological diagnosis. All the information of clinical, imaging and pathological changes were collected and analyzed.

Results

At the initial diagnosis, the BCVA of involved eyes decreased seriously while the IOP were normal. All involved eyeball showed extensive hyperemia and local thickening in the wall of eyeballs. B-scan ultrasonography showed mass with abundant blood and irregular cysts inside the eyeball wall and in the retrobulbar orbit, surrounding the ocular wall and optic nerve. UBM showed solid lesions with low and medium echo under the conjunctiva and inside the ciliary body of 2 cases. OCT showed posterior polar wavy rise of RPE and local neuroepithelial detachment in all cases. FFA and ICGA showed vascular abnormalities (patch-like strong fluorescence and fluorescence leakage) and local thickening in retina and choroid (Rectangle-like weak fluorescence below the macula). The posterior wall of the eyeball was thickened and enhanced in MRI. PET-CT also showed thickening of posterior wall of eyeballs and increased metabolic activity but there was no sign of autoimmune disease. All patients were diagnosed as MALT lymphoma through pathologic examinations of biopsy tissue.

Conclusions

The onset of primary ocular MALT lymphoma in uvea is hidden. The early clinical manifestations are lack of specificity and misleading. B-scan ultrasonography has characteristic manifestations and is valuable in diagnosis. However, pathological diagnosis through tissue biopsy is irreplaceable.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12886-022-02598-2.

Investigation of epidemiological characteristics and development of a nomogram to predict survival in primary ocular adnexal lymphoma

BACKGROUND

Studies on the epidemiology and prognosis of primary ocular adnexal lymphoma (POAL) are scarce for its low occurrence. The goal of our research was to assess the epidemiologic characteristics, prognostic variables and survival of POAL patients.

METHODS

The Surveillance, Epidemiology and End Results (SEER) database was used to collect data on patients identified with POAL from 1975 to 2011 and the incidence rate of POAL from 1975 to 2017. To discover independent predictive markers for overall survival (OS) and disease-specific survival (DSS), multivariable Cox regression analysis was utilised. The independent prognostic factors found by multivariate Cox regression analysis were used to generate a nomogram.

RESULTS

A total of 2839 patients were diagnosed with POAL, with an average age of 64.1 years. The total incidence of POAL was 2.51/1000000 (according to the overall adjustment of the 2000 American standard) from 1975 to 2017, and the annual percentage change (APC) was 2.47 (95% confidence interval 1.64-3.32, p < 0.05), showing a sharp upward trend. After multivariate Cox regression analysis, age, gender, year of diagnosis, marital status, primary site, laterality, pathological type and treatment strategy were evaluated as independent prognostic factors of OS or DSS (p < 0.05). A nomogram was constructed to forecast the DSS of 1, 3, 5 and 10 years. The concordance index (C-index) and the calibration plots demonstrated the robustness and accuracy of the nomogram.

CONCLUSIONS

Although POAL is sporadic, the incidence has generally increased in the past 36 years. In recent years, survival rates have risen, and radiotherapy can render better OS and DSS. The nomogram specially made for POAL is robust and precise in predicting the DSS of 1, 3, 5 and 10 years.

Chronic Inflammatory Orbitopathy Hiding Orbital Lymphoma

The incidence of lymphoma is constantly increasing worldwide. The reasons for this increase are unclear and likely multiple. B cell lymphomas represent the majority of non-Hodgkin lymphomas. Primary orbital localization remains a rare entity to think about in order to avoid missing a therapeutic emergency. In this article, we report the case of a 52-year-old man who has been treated for five years for an inflammatory orbitopathy with steroids, but the worsening of the clinical condition and the installation of exophthalmia led to push investigations and the outcome was a primary orbital lymphoma marginal zone type. The patient was treated by systemic chemotherapy with immunotherapy (RCHOP protocol) with a very good evolution and complete disappearance of the lesion after chemotherapy.

Histopathological Features and Ann Arbor Stage in Periocular Lymphoma

BACKGROUND

To evaluate biodata, symptoms/signs, lymphoma type, localization, stage level, treatment choice and outcome of ocular adnexal lymphoma (OAL).

PATIENTS AND METHODS

A single-center retrospective analysis of 56 patients with OAL was performed from 1998 to 2018.

RESULTS

OAL involved the orbit in 44.6%, the conjunctiva in 32.1%, the lacrimal apparatus in 14.3% and the eyelid in 8.93%. Extranodal marginal zone B-cell lymphoma (EMZL) was found in 60.7%, follicular lymphoma (FL) in 21.4%, diffuse large B-cell lymphoma in 7.14%, mantle cell lymphoma in 5.36% and chronic lymphatic leukaemia in 5.36% patients. No relapse was seen in 76%. EMZL and FL had a significantly better overall survival compared to other lymphoma types (p=0.002). Patients with Ann Arbor stage IE had a significantly better prognosis than those with stages higher than IE (p=0.048).

CONCLUSION

Our data suggest that clinicopathological features such as Ann Arbor stage influence survival.

Ocular adnexal lymphoma: A single-institution retrospective study

PURPOSE:

To characterize demographic, clinical, and histopathologic features of ocular adnexal lymphoma (OAL) at a single institution.

METHODS:

Retrospective review of all patients with pathologic diagnosis of OAL between 2015 and 2020.

RESULTS:

There were 133 patients with OAL, with a median age of 65 years (range 23–97) and a slight female predominance (male: female = 1:1.46), (n = 79, 59%). The majority of tumors were non-Hodgkin B-cell lymphomas (n = 131, 99%), most frequently Extranodal Marginal Zone B-Cell Lymphoma (EMZL, n = 93, 70%), followed by follicular lymphoma (n = 21, 16%), chronic lymphocytic leukemia/small lymphocytic lymphoma (n = 7, 5%), diffuse large B-cell lymphoma (n = 5, 4%), and mantle cell lymphoma (n = 5, 4%). The most frequently involved sites included the orbit (n = 85, 64%) and conjunctiva (n = 43, 32%). Information was available on oncologic staging in 78 (59%), treatment in 82 (62%), and follow-up in 75 (56%) patients. By the Ann-Arbor classification system, patients were classified as IE (54/78, 69%), IIE (9/78, 12%), IIIE (6/78, 8%), and IVE (9/78, 12%). The most common treatments included external beam radiotherapy (standard and ultra-low-dose) (48/82, 59%), biologics (22/82, 27%), and surgical excision with cryotherapy (14/82, 17%) (some patients had >1 therapy). Median follow-up time was 24 months (range 0–221 months). Recurrence was observed in 13% (10/75) with a median time to recurrence of 60 months (95% confidence interval 47–73 months). Excision with cryotherapy as a sole treatment modality was associated with earlier recurrence (P = 0.003).

CONCLUSION:

In this largest single-center study of OAL, we found that most OAL were Ann-Arbor Stage IE EMZL, occurring in older patients with a female predominance. Early recurrence was noted in tumors treated with excision and cryotherapy alone.

Orbital and ocular adnexal lymphoma: a review of epidemiology and prognostic factors in Taiwan

PURPOSE

To investigate the clinical features, prognostic outcomes of patients with orbital and ocular adnexal lymphoma (OALs) in Taiwanese cohort.

METHODS

Total 112 patients with OALs were retrospectively reviewed. Demographic information such as age, gender, lymphoma subtype, tumor location and treatment modalities were recorded. The primary endpoints were disease-specific survival (DSS), and progression-free survival (PFS).

RESULTS

The mean patient age was 59.0 ± 15.5 years (range, 23-92 years). The major histopathologic subtypes were mucosa-associated lymphoid tissue (MALT) lymphoma in 76 patients (67.9%), followed by diffuse large B-cell lymphoma (DLBCL) (9.8%), follicular cell lymphoma (FL) (8.0%), and small lymphocytic lymphoma (SLL) (5.4%). The anatomical locations for OALs were the orbit (44 patients, 39.3%), the conjunctiva (31 patients, 27.7%), the lacrimal gland (28 patients, 25.0%), and the eyelid (8 patients, 7.1%). With a mean follow-up time of 74.5 ± 59.8 months (range 6-342 months), the DSS for all patients were 93.1%, 87.7%, and 68.8% at 60, 120, and 180 months' follow-up, respectively. The PFS at 60, 120, and 180 months' follow-up were 86.2%, 61.2%, and 44.6%, respectively. Regarding the analysis of prognostic factors, patients with high grade lymphoma subtype and advanced stage exhibited a worse prognosis.

CONCLUSIONS

MALT type lymphoma constitutes most of OALs in Taiwan and occurs more frequently than in Western countries. Patients with MALT lymphoma, FL, SLL and earlier stage have favorable outcomes compared with patients of high grade lymphoma and Ann Arbor stage IV lymphoma.

Epidemiology, outcomes, and prognostic factors of orbital lymphoma in the United States

PURPOSE

We performed an epidemiological study of orbital lymphoma in the United States to determine how histological subtypes confer differing prognosis, and understand other factors associated with survival.

METHODS

All patients in the Surveillance, Epidemiology and End Results database diagnosed with a histologically confirmed orbital lymphoma between 1973 and 2014 were included. Exclusion criteria included diagnosis at autopsy and the presence of other malignancies. Measures included patient demographic information, histological subtype and treatment modalities. Outcomes included overall and disease specific survival.

RESULTS

Of the 1504 cases identified, 702 were male (46.7%, mean age: 64.4 years, standard deviation [SD]: 15.3) and 802 were female (53.3%, mean age: 67.5 years, SD: 14.3). Mucosal associated lymphoid tissue (MALT) (49.5%) and diffuse large B cell lymphoma (DLBCL) (19.5%) were the two most common histologic subtypes. MALT lymphoma conferred the best prognosis (10-year cancer specific survival [CSS] 90.2%, 95% Confidence Interval [CI] 87.4% - 93.1%) and DLBCL conferred the worst prognosis (10-year CSS 68.6%, 95% CI 62.5% - 75.3%) (p < .001, log-rank test). Older age (Hazard Ratio [HR]: 3.71, 95% Confidence Interval [CI]: 2.94-4.66, p < .001), male sex (HR: 1.22, 95% CI: 1.039-1.441, p = .015), no radiation (HR: 1.72, 95% CI: 1.46-2.02, p < .001) and DLBCL histology were significant predictors of worse overall survival.

CONCLUSIONS

DLBCL histology confers the worst outcomes whereas MALT lymphoma confers the best outcome in orbital lymphoma. Age, gender, and radiation treatment also influence survival. These epidemiological results can be used clinically to communicate outcomes on the basis of patient characteristics and disease histology.

Epidemiology of ophthalmic lymphoma in Canada during 1992-2010

BACKGROUND

Ophthalmic lymphoma (OL) is the most common orbital tumour, particularly in older individuals. Little is known about the epidemiology and geographic distribution of OL in Canada. Descriptive demographic statistics are an important first step in understanding OL burden and are necessary to inform comprehensive national cancer prevention programmes.

METHODS

We determined patterns of incidence and geographical distribution of the three major subtypes of OL: extranodal marginal zone B cell lymphoma, follicular lymphoma (FL) and diffuse large B cell lymphoma. Here, we used cases that were diagnosed during 1992-2010 using two independent population-based cancer registries, the Canadian Cancer Registry and Le Registre Québécois du Cancer (LRQC).

RESULTS

The OL mean annual age-standardised incidence rate for 1992-2010 was 0.65 cases per million people per year with an average annual increase in the incidence rate of 4.5% per year. The mean age of diagnosis was 65 years. OL incidence rate was the highest in the cities located along the heavily industrialised Strait of Georgia in British Columbia.

CONCLUSIONS

Our data on patient age, sex and temporal trends showed similarities with data reported in the USA and Denmark. Additional studies are needed to determine whether the observed increase in OL incidence is genuine or spurious.

Understanding and Classification of Ocular Lymphomas

BACKGROUND

Lymphomas that involve the tissues of the ocular adnexae and the eye itself can be confusing for both the new and seasoned learner alike. In this review, I present a simple way of classifying these disorders that will help to facilitate understanding of these myriad entities.

SUMMARY

Classifications of lymphomas have changed significantly over the last 40 years, but in recent decades, the basic structure of the WHO classification has remained the same, facilitating understanding.

KEY MESSAGES

The ocular lymphomas can be divided into those that are external to the eye (ocular adnexae) and those that are internal (vitreoretinal and uveal). At each of these sites specific subtypes of lymphoma are common. Focusing on these common subtypes can aid the learner to create a scaffold that enables current understanding and upon which they can build for the future.

Case Report: Primary Conjunctival Non-Hodgkin Marginal Zone Lymphoma

SIGNIFICANCE

Ophthalmic manifestations of non-Hodgkin lymphoma are rare, and the diagnosis can be delayed because of nonspecific symptoms and a tendency to mimic the appearance of other ocular diseases. Suspicious presentations will require confirmation of the lymphoma through surgical biopsy.

PURPOSE

The purpose of this study was to present an isolated conjunctival non-Hodgkin marginal zone lymphoma without systemic involvement, which was successfully managed with external beam radiation.

CASE REPORT

A 49-year-old man reported a red, temporal bulbar conjunctival growth on the left eye for several weeks, which was initially treated as a nodular episcleritis. When the condition did not resolve, a subsequent biopsy diagnosed a low-grade non-Hodgkin marginal zone lymphoma; further testing found no systemic involvement. No intraocular involvement was noted, and B-scan ultrasound and magnetic resonance imaging did not demonstrate any uveal or orbital extension. A trial of doxycycline did not lead to regression, and the isolated lesion was observed. Because of possible slow growth, the lesion was eventually treated with external beam radiation, which resulted in significant tumor regression. Four years after the radiotherapy, the tumor has not recurred, and there has been no systemic involvement.

CONCLUSIONS

This case of a low-grade extranodal marginal zone lymphoma on the temporal conjunctiva represents a less common variation of the classic fornix-based presentation. It is not unusual for conjunctival lymphomas to masquerade as another clinical entity, sometimes making the initial diagnosis challenging. If a patient does not respond as expected to conventional therapy, a biopsy to rule out malignancy should be considered.

Treating synchronous bilateral ocular adnexal marginal zone lymphoma: the consortium for improving survival of lymphoma study

Both-side synchronous involvement has been reported to account for 7-24% of ocular adnexal marginal zone lymphoma (OAML). We conducted a retrospective analysis to identify the clinical features and treatment outcomes of synchronous bilateral OAML (SB-OAML) by treatment modality. We analyzed patients with a histologic diagnosis of SB-OAML, excluding metachronous bilateral involved OAML. We enrolled a total of 95 patients for this analysis, 36 males and 59 females; the median patient age was 42 years (range 16-77 years). Eleven (11.6%) patients had been treated with chemotherapy or chemo-immunotherapy (eight R-CVP, two CVP, and one R-CHOP). The median number of treatments was 6 (range 6-8); there were 9 complete responses (CRs; 81.8%) and 2 partial responses (PRs; 18.2%). Nearly all patients (88.4%) received radiotherapy in both eyes, and the median radiation dose was 27 Gy (range 20-40 Gy) to each eye; 68 CRs (80.9%) and 14 PRs (16.7%) were achieved. Ten-year progression-free survival (PFS) and overall survival (OS) rates were 79.8 and 91.1%, respectively. Radiotherapy continued to be an independent prognostic marker, with the hazard of progression (P = 0.036). Eleven patients (13.1%) had surgery for cataract treatment during follow-up, and patients who received low-dose radiation (< 30.3 Gy) experienced fewer cataract operations. SB-OAML was predominantly observed in young females, and they had good response and prognosis regardless of treatment modalities. Low-dose radiotherapy to both eyes showed a tendency of longer PFS than did chemotherapy and could decrease cataract operations.

Incidence of orbital, conjunctival and lacrimal gland malignant tumors in USA from Surveillance, Epidemiology and End Results, 1973-2009

AIM

To determine the types and incidence of tumors affecting the orbit, conjunctiva and lacrimal glands and to study the trend line of these tumors in the United States from 1973 to 2009.

METHODS

We used the publicly available Surveillance, Epidemiology and End Results (SEER) database registries to determine the incidence rates. Age was adjusted to the 2000 US Standard Population. Patients were stratified according to age group, gender, race and histological grouping of tumor lesions. Three age groups were defined: 0-19, 20-49 and ≥50y. Annual percentage changes were calculated to examine trends.

RESULTS

The overall age adjusted incidence rate was 3.39 (95%CI: 3.27-3.52) per million person-years. The tumors were more prevalent in age group ≥50 counting 9.51 (95%CI: 9.11-9.92) per million person-years. Most of the soft tissue sarcomas occurred in the young age with incidence rate of 0.35 (95%CI: 0.28-0.42) per million person-years. Lymphomas were the dominant subtype in the adult population with incidence rate of 5.74 (95%CI: 5.43-6.06) per million person-years. Incidence rates were higher in males than females with an overall rate ratio of 1.31 (95%CI: 1.21-1.41) mainly caused by the increase in carcinoma subtypes. White race had a higher tumor incidence with a rate ratio of 1.47(95%CI: 1.25-1.73) driven by the higher incidence of most histological subtypes. Orbital tumors showed a higher incidence rate followed by conjunctival and lacrimal gland tumors with incidence rates of 1.59, 1.37 and 0.43 per million person-years respectively. The trend line of overall incidence of tumors showed a significant increase (APC=3.11, 95%CI: 2.61-3.61) mainly due to increase of lymphomas. This increase was higher than the increase of lymphomas at other sites.

CONCLUSION

Orbital, conjunctival and lacrimal gland malignant tumors differ among children and adults. Over the years there has been a noticeable increase in incidence rates of orbital and lacrimal gland tumors mainly caused by an increase in lymphomas and an apparent increase due to advances in diagnostic techniques. ICD-O-3 topographical coding should be improved to consider the different orbital bones and ocular structures.

Ocular adnexal marginal zone lymphoma: Clinical presentation, pathogenesis, diagnosis, prognosis, and treatment

Ocular adnexal marginal zone lymphoma (OAML) represents 1-2% of all non Hodgkin lymphomas. In the last few years many advances in understanding the pathogenesis and the molecular basis involved in its development have been done. Many potential risk factors have been proposed; a dysregulation of immune response in association with a chronic antigenic stimulation, have been hypothesized as possible pathogenic mechanism. In particular, Chlamydia psittaci infection has been related to OAML arising, and eradicating antibiotic therapy has been addressed as a safe and cost-effective approach. Management of OAML is still heterogeneous and matter of debate. There is no consensus about the best upfront treatment and therapeutic decision should take into account several patient-, lymphoma- and treatment-related factors. Novel agents and chemotherapy-free strategies are being investigated to reduce side effects and improve tumor control. This review is focused in recent knowledge improvements in this lymphoma.

ORBITAL AND ADNEXAL LYMPHOMAS AMONG ADULT PATIENTS IN GHANA

BACKGROUND

Non Hodgkin's lymphomas (NHLs) present variously in different ethnic communities. Orbital and adnexal disorders have been reported among NHLs in Africa. They can involve the orbit, the eyelid, the conjunctiva, alone or in combinations. To our knowledge there are no reports in the literature about the clinical presentation of lymphomas in Ghana.

AIM

To explored orbital and adnexal disorders among adult patients attending the Korle-Bu Teaching hospital, Accra.

METHODOLOGY

Histological case notes of patients reporting to the orbital clinic of Korle-Bu Teaching Hospital, Eye Department from November 2004 to October 2016 with orbital and adnexial lympho-proliferative tumors were retrieved. Histopathology was performed at Sheffield Teaching hospital. Data collected included age, sex, symptoms at presentation and anatomic site of involvement. Histology and immune histochemistry data were generated.

RESULTS

A total of 18 patients were examined and entered into the study. The male to female ratio was 1.25:1. Twelve patients (70.6) presented with proptosis and 14 (77.8%) had orbital involvement. Two patients had isolated eyelid disease. Of those with orbital disease, three had simultaneously upper eyelid involvement. Out of the 18 cases, 11 (61.1%) were mucosa-associated lymphoid tissue (MALT) lymphomas. Only males 40 years and above were affected, compared with females who presented at any age. Patients above 60 years reported early (i.e. <3 months) compared with patients below 40 years who mostly reported after 1 year.

CONCLUSION

This study reports pattern of epidemiological and clinical presentation of orbital and adnexal lymphomas as seen in Ghana, West Africa. Though there were some variations in the clinical presentation the histological subtypes represented seem to be similar to those reported in other parts of the world.

An update on ocular adnexal lymphoma

Ocular adnexal lymphoma (OAL) is a relatively common lesion in the practice of ophthalmic oncology. Although OALs are usually primary tumors, secondary involvement of the ocular adnexae by systemic lymphoma is also possible. The clinical and radiological features of OAL are non-specific. Thorough morphological evaluation, aided by immunostaining, cytogenetic studies and molecular testing, are necessary for accurate diagnosis.

Orbital tumors in USA: difference in survival patterns

INTRODUCTION

There is a wide range of tumors affecting the orbital adnexa. Key such tumors include lymphomas, carcinomas, melanomas and rhabdomyosarcomas. Several studies have proposed that these histological subtypes differ in their survival outcomes. In this study we aim to describe the difference in survival outcomes between such subtypes.

METHODS

The SEER database was used to gather patient information. All 18 SEER registries were used. Patients diagnosed from 1996 to 2005 were included in the analysis. Observed five-year survival rate was calculated using the SEER*Stat software version 8.1.2. Data were extracted into IBM SPSS version 20 to generate Kaplan Meier curve for each group.

RESULTS

There were 2180 patients in the SEER databases who met the selection criteria. Lymphomas were the most common histology in adults. The overall five-year observed survival for all lymphoma patients was 75.9% (95% CI: 73.7-78.1). There was statistically significant difference between observed survival rates of lymphoma subtypes. Carcinomas were the second most common tumors. Their five-year observed survival rate in our study was 60.4%. There was no statistically significant difference between carcinoma subtypes' observed survival rates in the 20-49 age group, while, in the older age group, the difference was found to be statistically significant. Rhabdomyosarcomas were the most common tumors in children. The overall five-year observed survival rate for rhabdomyosarcomas patients was 89.8%. There was no statistically significant difference between observed survival rates of rhabdomyosarcomas subtypes. There was no statistically significant difference between relative survival rates according to gender and treatment received except within melanomas.

CONCLUSION

In adults, lymphomas have better survival rates than carcinomas. Whereas the lymphoma subtype can be used as a determinant prognostic factor in any age, the carcinoma subtype can be used as such a determinant in older age groups only. In children, rhabdomyosarcomas are the predominant tumors affecting the orbital adnexa. Further studies are needed to determine if the difference between embryonal rhabdomyosarcoma and alveolar rhabdomyosarcoma observed survival rates are statistically significant.

Ocular adnexal non-Hodgkin's lymphoma: a review of epidemiology and risk factors

Ocular adnexal non-Hodgkin's lymphoma (NHL), the most common form of ophthalmic NHL, has a unique incidence pattern showing a steady and rapid increase in the past few decades, nearly equal rates among both genders, and predominance among Asians/Pacific Islanders. No major cause for ocular adnexal NHL has been identified, although infectious agents, immune disorders and genetic/epigenetic factors have all been implicated in its etiology. Identifying putative risk factors and biologic mechanisms leading to carcinogenesis in ocular adnexal NHL may enable implementation of effective preventive and/or therapeutic approaches for this malignancy. This article summarizes current knowledge on epidemiology of ocular adnexal NHL and the role of various potential risk factors in its etiology.