[Plasmablastic lymphoma presenting with plasmacytosis and polyclonal hypergammopathy].

A 72-year-old woman presented with generalized lymphadenopathies and plasmacytosis accompanied by polyclonal hypergammopathy. 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) showed FDG accumulation in the systemic lymph nodes, spleen, and multiple bones. Human immunodeficiency virus antibody was negative. Lymph node histologic findings showed a monotonous population of plasma cells with a starry-sky appearance. The cells were positive for CD19, λ, and Epstein-Barr virus-encoded RNA, and negative for CD20 and CD56. The MIB-1 index was 80%. A diagnosis of plasmablastic lymphoma with plasmacytosis and polyclonal hypergammopathy was made, and complete metabolic response was achieved after six cycles of dose-adjusted-EPOCH therapy (etoposide, prednisolone, vincristine, cyclophosphamide, and doxorubicin).

Plasmablastic lymphoma: current knowledge and future directions.

Plasmablastic lymphoma (PBL) is an aggressive non-Hodgkin lymphoma associated with HIV infection and immunodeficiency. However, PBL can also be seen immunocompetent individuals in recent studies. PBL was characterized by distinct clinical and pathological features, such as plasmablastic morphology and universal expression of plasma cell markers. The clinicopathologic features were different between HIV-negative and HIV-positive patients. Gene expression analysis identified the unique molecular feature in PBL, including frequent c-MYC rearrangement and downregulation of BCR signaling pathway. Despite the recent advances in the treatment of PBL, the prognosis of PBL patients remains dismal. The objectives of this review are to summarize the current knowledge on the epidemiology, molecular profiles, clinical and pathological features, differential diagnosis, treatment strategies, prognostic factors, and potential novel therapeutic approaches in PBL patients.

FLI-1 is expressed in a wide variety of hematolymphoid neoplasms: a special concern in the differential diagnosis.

Friend Leukemia Virus Integration 1 (FLI-1) is a member of E26 transformation-specific family of transcription factors that participates in hematopoietic and vascular endothelial cell development. Immunohistochemical detection of FLI-1 has been widely used to diagnose vascular tumors or, more evidently, Ewing's sarcoma. However, the expression pattern of FLI-1 in hematolymphoid neoplasms remains unclear. Therefore, in this study, we aimed to investigate the expression of FLI-1 in these tumors, focusing on high-grade lesions, which presents a diagnostic challenge by mimicking Ewing's sarcoma. We evaluated the expression FLI-1 in various types of lymphoid and plasmacytic tumors, including 27 plasmablastic lymphomas, 229 diffuse large B-cell lymphomas, 22 precursor T- or B-lymphoblastic lymphomas, 24 angioimmunoblastic-type nodal T-follicular helper cell lymphomas, 52 peripheral T-cell lymphomas, NOS, 18 Burkitt lymphomas, 18 non-gastric lymphomas of mucosa-associated lymphoid tissue, 38 chronic lymphocytic leukemia/small lymphocytic lymphomas, 15 mantle cell lymphomas, 23 gastric MALT lymphomas, 50 plasma cell myelomas, and 38 follicular lymphomas. We calculated the H-scores of FLI-1 immunostaining, ranging from 0 to 200, and used the scores to analyze the clinicopathological significance of FLI-1 statistically. FLI-1 was expressed to varying degrees in all types of hematological tumors. FLI-1 expression was detected in 84.1% of patients (466/554). FLI-1 was highly expressed in precursor T- or B-lymphoblastic lymphomas. Follicular lymphomas exhibited low FLI-1 expression. In plasmablastic lymphoma, 85.2% of the patients were focally positive for FLI-1. FLI-1 expression did not correlate with clinicopathological variables, such as demographic data or disease stage, in patients with plasmablastic lymphoma and diffuse large B-cell lymphoma. However, FLI-1 overexpression was associated with poorer overall survival in patients with plasmablastic lymphoma. This study demonstrates that FLI-1 is expressed in various hematolymphoid neoplasms. FLI-1 expression can lead to diagnostic confusion, especially in small blue round cell tumors, such as lymphoblastic lymphoma, plasmablastic lymphoma, and plasma cell myeloma, when distinguishing tumors positive for CD99 and CD56 without CD3, CD20, or CD45. Our findings also suggested the possibility of FLI-1 as a potential prognostic biomarker for plasmablastic lymphoma.

Epidemiologic Characteristics, Treatment Patterns, and Survival Analysis of Plasmablastic Lymphoma in the United States: A SEER and NCDB Analysis.

BACKGROUND: Plasmablastic Lymphoma (PBL) is a rare aggressive B-cell lymphoma that primarily affects immunocompromised individuals, including those living with HIV. Historically, survival estimates are dismal and range from 8 to 15 months. We aimed to evaluate epidemiologic characteristics, treatment patterns and survival trends on a national scale. PATIENTS AND METHODS: Patients diagnosed with PBL from 2010 to 2020 were identified in the National Cancer Database (NCDB) and in the Surveillance, Epidemiology, and End Results (SEER) program. Incidence rates were calculated using SEER. Demographic features, treatment characteristics, and overall survival (OS) were identified using the NCDB. RESULTS: We identified 1153 patients in the SEER database and 1822 patients in the NCDB. The incidence of PBL is 0.07 cases per 100,000 US population per year. PBL is more common in males (77%), and white patients (77%), with 50% of cases in patients with HIV. Patients who were treated with multiagent chemotherapy had a median OS of 58.6 months. On multivariate Cox regression, we found that HIV status did not have a significant impact on OS. Factors associated with worse OS included advancing age and stage. CONCLUSION: We present the largest study to date on PBL. Among treated patients, we described a median OS of 58.6 months, greatly improved from previously reported estimates. We found that HIV status did not have a significant impact on OS. While OS remains poor, therapeutic advances over the last decade are promising and highlight the need for continued clinical advances aimed at improving therapeutic options for this rare lymphoma.

The influence of immunodeficiency, disease features, and patient characteristics on survival in plasmablastic lymphoma.

ABSTRACT: Plasmablastic lymphoma (PBL) is a rare and aggressive non-Hodgkin lymphoma associated with immunodeficiency, characterized by uncertain treatment approaches and an unfavorable prognosis. We conducted a multicenter, international, retrospective cohort study, aiming to characterize the clinical features, risk factors, and outcomes of patients with PBL. Data were collected from 22 institutions across 4 countries regarding patients diagnosed with PBL between 1 January 1999 and 31 December 2020. Survival risk factors were analyzed using both univariate and multivariate regression models. Overall survival (OS) was calculated using Kaplan-Meier statistics. First-line treatment regimens were stratified into standard- and higher-intensity regimens, and based on whether they incorporated a proteasome inhibitor (PI). A total of 281 patients (median age, 55 years) were included. Immunodeficiency of any kind was identified in 144 patients (51%), and 99 patients (35%) had HIV-positive results. The 5-year OS for the entire cohort was 36% (95% confidence interval, 30%-42%). In multivariate analysis, inferior OS was associated with Epstein-Barr virus-negative lymphoma, poor performance status, advanced stage, and bone marrow involvement. In an independent univariate analysis, the international prognostic index was associated with OS outcomes. Neither immunosuppression nor HIV infection, specifically, influenced OS. Among patients treated with curative intent (n = 234), the overall response rate was 72%. Neither the intensity of the treatment regimen nor the inclusion of PIs in first-line therapy was associated with OS. In this large retrospective study of patients with PBL, we identified novel risk factors for survival. PBL remains a challenging disease with poor long-term outcomes.

Clinicopathological and genetic landscape of plasmablastic lymphoma in Taiwan.

Plasmablastic lymphoma (PBL) is an aggressive large B-cell lymphoma with a terminal B-cell differentiation phenotype and is frequently associated with immunodeficiency. We aimed to investigate the clinicopathological and immunophenotypic features, genetic alterations, and mutational landscape of PBL in Taiwan. We retrospectively recruited 26 cases. Five (5/18; 28%) patients were HIV-positive and 21 (81%) presented extranodally. There were two morphological groups: one with purely monomorphic large cells (85%) and the other comprising large cells admixed with plasmacytic cells (15%). Phenotypically, the tumors expressed MYC (8/10; 80%), CD138 (20/26; 77%), and MUM1 (20/20; 100%), but not CD20 (n = 26; 0%). Fourteen (54%) cases were positive for EBV by in situ hybridization; the EBV-positive cases were more frequently HIV infected (p = 0.036), with extranodal presentation (p = 0.012) and CD79a expression (p = 0.012), but less frequent light chain restriction (p = 0.029). Using fluorescence in situ hybridization, we identified 13q14 deletion, MYC rearrangement, and CCND1 rearrangement in 74%, 30%, and 5% cases, respectively, without any cases having rearranged BCL6 or IGH::FGFR3 fusion. In the 15 cases with adequate tissue for whole exome sequencing, the most frequent recurrent mutations were STAT3 (40%), NRAS (27%), and KRAS (20%). In conclusion, most PBL cases in Taiwan were HIV-unrelated. Around half of the cases were positive for EBV, with distinct clinicopathological features. Deletion of chromosome 13q14 was frequent. The PBL cases in Taiwan showed recurrent mutations involving JAK-STAT, RAS-MAPK, epigenetic regulation, and NOTCH signaling pathways, findings similar to that from the West.

Exploring TBL1XR1 and NCOR1 Expression in B-cell Lymphoma Subtypes: Interaction With DNA Damage Repair Genes.

BACKGROUND/AIM: B-cell lymphomas are characterized by diverse genetic anomalies affecting B-cell differentiation. To expand targeted therapies, an in-depth grasp of the molecular dynamics in the germinal center (GC) is vital. Transducin ß-like 1 X-linked receptor 1 (TBL1XR1) and nuclear receptor corepressor 1 (NCOR1) are instrumental within the GC, modulating myriad oncogenic pathways. Their prognostic roles in various cancers are established, yet their precise impact on B-cell lymphoma is elusive. MATERIALS AND METHODS: Digital RNA quantification (Nanostring) of previously curated 188 B-cell lymphoma specimens across four subtypes, follicular lymphoma (FL), diffuse large B-cell lymphoma, not otherwise specified (DLBCL-NOS), primary testicular lymphoma (PTL), and plasmablastic lymphoma (PBL), was reanalyzed with focus on TBL1XR1 and NCOR1 expression, juxtaposing them with 730 ontogenically linked genes. RESULTS: Notably, TBL1XR1 expression was significantly elevated in the PTL- ABC-subtype versus DLBCL-NOS- ABC-subtype (p<0.001), with no marked disparity in GCB-subtypes between them. The median TBL1XR1 expression was remarkably diminished in FL, yet, intriguingly, GCB-subtypes of DLBCL-NOS exhibited significantly enhanced expression compared to FL (p=0.001). In contrast, NCOR1's expression trajectory was consistent across DLBCL-NOS, PTL, and PBL. A strong inverse correlation between TBL1XR1 and NCOR1 was observed in PBL (p=0.001). Importantly, TBL1XR1's pronounced association with several DNA Damage repair (DDR) genes was noted suggesting influence on DNA repair. TBL1XR1-DDR gene signature was further validated employing a public data set of DLBCL-NOS. CONCLUSION: Our exploratory findings unravel the expression patterns of TBL1XR1/NCOR1 in B-cell lymphoma variants. The TBL1XR1-DDR genes connection offers insights into potential DNA repair roles, paving avenues for innovative therapies in B-cell lymphomas.

A challenging diagnosis of plasmablastic lymphoma: importance of integrating morpholgy immunohistochemistry and flow cytometry findings (case report).

Plasmablastic lymphoma (PBL) is a rare clinicopathological entity that still raises many diagnostic and management difficulties, particularly due to the overlap between plasmablastic lymphomas and myeloma features. We report a clinical presentation of PBL affecting bone marrow in a 43-year-old patient who was admitted for B symptoms, hepatosplenomegaly, and bicytopenia investigation. Based on these findings, acute leukemia was suspected. Bone marrow morphology immunohistochemistry and flow cytometry contributed to establishing the diagnosis of medullary PBL. The patient deteriorated and died due to septic shock. This pathology requires collaboration between clinicians, pathologists, and biologists to confirm the diagnosis early. Nevertheless, a delayed diagnosis may contribute to worsening the prognosis particularly due to advanced stage consultation. Our reported case illustrates a rare clinical presentation affecting bone marrow. In our context, a confrontation between flow cytometry and immunohistochemistry was of interest as it helped to detect the immunological features of this neoplasm.

Proliferative glomerulonephritis with monoclonal IgG Lambda deposits caused by plasmablastic lymphoma: a case report.

INTRODUCTION: As a very rare form of B-cell lymphoma, plasmablastic lymphoma (PBL) typically occurs in patients with underlying immunosuppression, including human immunodeficiency virus (HIV), organ transplantation, and autoimmune diseases. For HIV-positive patients, PBL normally originates in the gastrointestinal tract, especially from the oral cavity in most cases. It is extremely rare to find abdominal cavity involvement in PBL, and there has been no previously reported instance of proliferative glomerulonephritis with monoclonal immunoglobulin deposits (PGNMID) attributed to monoclonal IgG (MIgG) lambda secreted by PBL. CASE PRESENTATION: We report the case of an HIV-negative female with nephrotic syndrome, renal insufficiency, and multiple swollen lymph nodes. Ascitic fluid cytology revealed a high level of plasmablast-like lymphocytes with the restriction of lambda light chains. Besides, the renal biopsy revealed PGNMID, which could presumably be secondary to MIgG-lambda-secreting by PBL. MIgG-lambda-restricted expression was discovered earlier in the kidney tissue than in the blood. CONCLUSION: The diagnostic landscape for PBL is notoriously intricate, necessitating a multifaceted and nuanced approach to mitigate the risks of erroneous identification.

Duodenal plasmablastic lymphoma in an human immunodeficency virus-negative patient: a case report.

BACKGROUND: Plasmablastic lymphoma is a rare type of non-Hodgkin lymphoma that generally presents an aggressive clinical course. It is strongly associated with human immunodeficency virus (HIV) infection, and the most common site of involvement is the oral cavity. Although extraoral PBL has been reported in several places, small intestine involvement is extremely rare. CASE PRESENTATION: Here, we describe an exceptionally rare case of a 24-year-old immunocompetent Asian Male patient with newly diagnosed plasmablastic lymphoma of the duodenum. The patient was admitted to our oncology facility due to the patient's clinical course, which included persistent vomiting, hematemesis, weight loss, and generalized weakness. Computed tomography of the abdomen (triphasic) of the patient showed thickness at the 2nd part of the duodenum measuring 2.6 cm in width and 16 cm in length blocking the pancreatic and common bile ducts by entering the second section of the duodenum. The biopsy specimen's pathological investigation indicated abnormal cells with plasmacytoid characteristics and a high proliferation index. The diagnosis of PBL was confirmed by immunohistochemical profiling. Supportive therapies like blood transfusions, antacids, and antiemetics were started to manage the patient's symptoms. Palliative radiation was also anticipated for the lesion site. CONCLUSIONS: Duodenal involvement to the extent seen in our patient is exceptionally rare and, to the best of our knowledge, has hardly been described. The main goal of the article is to review the literature and report a case.

Primary plasmablastic lymphoma of the gastrointestinal tract: A series of 13 HIV-negative cases and a review of literature.

CONTEXT: Primary gastrointestinal plasmablastic lymphoma (GI-PBL) is a rare variant of diffuse B-cell lymphoma with an aggressive clinical course. PBL was initially reported among HIV-positive patients; however, subsequent studies have shown that it also occurs among HIV-negative patients. Its clinical characteristics remain poorly understood. This study aims to retrospectively analyze the clinicopathological findings of primary GI-PBLs in HIV-negative patients. DESIGN: Primary HIV-negative GI-PBL cases from 2008 to 2022 were reviewed. Clinicopathologic features and outcomes were analyzed. RESULTS: The cohort of 13 patients had a male-to-female ratio of 9:1 (3 patients' genders not available), with an average age of 61 (range, 30-92) years. The most involved location was the colon (n = 7 [53.8 %]), followed by the small bowel (n = 3 [23.1 %]), stomach (n = 2 [15.4 %]), rectum (n = 1 [7.7 %]), and anus (n = 1 [7.7 %]). Most patients (n = 10 [77 %]) showed isolated GI tract involvement. Eight patients had chronic inflammatory and/or immunocompromised status, including 4 with inflammatory bowel disease (all of whom underwent treatment), 3 with post-organ transplant status, and 1 with irritable bowel syndrome. All cases exhibited cytokeratin-/CD20-/PAX-5-/CD138+ and/or MUM1+ immunophenotype. Based on available data, 8 of 11 (72.7 %) patients had Epstein-Barr virus reactivation. Among 11 patients with follow-up data, the mean follow-up duration was 13.5 (range, 3-40) months; at the end of follow-up, 45.5 % of patients (5 of 11 patients) showed complete remission after chemotherapy. CONCLUSION: Primary HIV-negative GI-PBL occurs predominantly in the colon of relatively elderly males with immunosuppression. Its clinical course can be heterogenous, presenting a comorbidity with inflammatory bowel disease or post-organ transplantation status.

Plasmablastic Lymphoma in a Human Immunodeficiency Virus-positive Child With a Suspicion of Concomitant Primary Immunodeficiency Disorder.

Plasmablastic lymphoma (PBL) occurs in the setting of immunodeficiency, in association with human immunodeficiency virus (HIV) infection, in elderly patients, and in the posttransplantation state. It is exceptionally rare in children. PBL is an aggressive lymphoma with a poor prognosis. We present a case of pediatric PBL in an HIV-positive child with suspicion of a concomitant underlying immune deficiency state other than HIV. A 7-year-old girl presented to the pediatric emergency department with complaints of fever and painful swelling on the left side of her face for 15 days, associated with headache, snoring, and difficulty in breathing. She had a history of watery diarrhea, oral thrush, recurrent fever, and hospitalizations for skin infections since the age of 1 year. Histopathological findings were consistent with PBL. Her HIV RNA polymerase chain reaction was positive. She was offered chemotherapy based on the FAB/LMB 96 protocol. This case demonstrates an aggressive presentation of a rare entity, HIV-associated PBL, in a child, with underlying immunodeficiency and highlights the issues which caused a significant challenge in making the diagnosis. The presence of HIV infection and contradicting other immunologic investigations posed a dilemma in establishing an association of PBL in this child. The outcome of patients with this tumor is associated with high mortality.

From the archives of MD Anderson Cancer Center: Plasmablastic lymphoma presenting as a kidney mass in an immunocompetent patient: Case report and literature review.

BACKGROUND: Plasmablastic lymphoma (PBL) is a rare, aggressive large B-cell lymphoma with plasmablastic or immunoblastic morphology and a terminally differentiated B-cell immunophenotype. PBL often presents at extranodal sites, commonly the oral cavity of immunocompromised patients with human immunodeficiency virus (HIV) and/or Epstein-Barr virus (EBV) infection. Cases of PBL arising outside the oral cavity in previously healthy immunocompetent patients are rare. CASE REPORT: We report a 65-year-old HIV- and EBV-negative man who presented with abdominal pain, fatigue, and vomiting. Imaging studies showed a 30 × 18 cm bulky lobulated mass located within the left kidney with surrounding para-aortic lymphadenopathy. Serum and urine protein electrophoresis revealed a monoclonal gammopathy of IgA lambda type. Biopsy of the mass showed PBL. Bone marrow lumbar puncture evaluations also showed evidence of PBL. The patient was treated with chemotherapy and radiation with initial improvement; however, he died 14 months after initial diagnosis. CONCLUSIONS: Based on our literature review, this case of PBL is one of the few reported to present as a kidney mass in immunocompetent, HIV- and EBV-negative patient. Distinguishing PBL from plasma cell myeloma (PCM) can be challenging. Knowledge of clinical features including presence of CRAB (hypercalcemia, renal failure, anemia, bone lesions) or bone marrow infiltration by mature clonal plasma cells is helpful to establish a diagnosis of PCM. Genetic features of PCM (typical translocations or mutations) also can be helpful in distinguishing plasmablastic transformation of PCM and from PBL. The case we report also highlights the need for more studies to identify specific immunohistochemical and molecular markers to improve PBL diagnosis in immunocompetent patients.

Cytological features of oral malignant lymphoma in scraping liquid-based cytology: Cases of plasmablastic lymphoma and anaplastic lymphoma kinase-positive anaplastic large cell lymphoma.

The main purpose of cytological examination in the oral region is to screen for squamous cell carcinoma or intraepithelial neoplasms; thus, the background tends to be considered a deterrent for microscopy. From this perspective, liquid-based cytology (LBC) is favorable for preparing clear samples with few backgrounds. However, background hemocytes are sometimes of critical importance in the diagnosis. We report two cases of oral malignant lymphoma, plasmablastic lymphoma, and anaplastic large cell lymphoma in which careful observation of the background in scraping LBC sample contributed to the early diagnosis. Atypical lymphoid cells were observed only in a very small part of the LBC samples from the presented patients; however, cytological findings, such as large lymphoid cells with outstanding nucleoli, large mitotic cells, or intermediate-to-large lymphoid cells with pleomorphic nuclei were sufficient for obtaining a cytological diagnosis of malignant lymphoma. Although the number and cell size of leukocytes in LBC with Papanicolaou staining were significantly different from those in air-dried conventional smears with Romanovsky staining, which are commonly preferred for the discrimination of hemocytes, the corresponding cytological features could be observed. Therefore, attention should be paid to the background as well as squamous epithelium to prepare for such unexpected cases. The LBC examination with Papanicolaou staining alone can suggest the possibility of malignant lymphoma.

Unraveling the molecular landscape: a comparative analysis of PI3K and MAPK signaling pathways in plasmablastic lymphoma and diffuse large B-cell lymphoma with therapeutic implications.

Plasmablastic lymphoma (PBL) is a rare and aggressive subtype of non-Hodgkin lymphoma that shares features with diffuse large B-cell lymphoma (DLBCL). While significant progress has been made in treating DLBCL, the prognosis for PBL remains poor, highlighting the need to identify new therapeutic targets. Using RNA expression analysis, we compared the expression of genes involved in the phosphatidylinositol-3-kinase (PI3K) and mitogen-activated protein kinase (MAPK) signaling pathways between PBL and DLBCL. We used critical PI3K (n = 201) and MAPK (n = 57) signaling probe sets to achieve this objective. Our results demonstrate unique molecular mechanisms underlying PBL pathogenesis compared to DLBCL, particularly within the PI3K and MAPK signaling pathways. We found that elevated STAT3 expression in PBL correlates with hyperactive MAPK and PI3K pathways, unlike DLBCL. Additionally, the hyperactivation of the PI3K signaling axis in PBL is unrelated to B-cell receptor or phosphatase and tensin homolog activity, indicating a distinct mechanism compared to DLBCL. Furthermore, we observed unique activation patterns in MAPK pathways between PBL and DLBCL, with PBL exhibiting high expression of the neurotrophic tyrosine kinase receptor (NTKR) family, specifically NTRK1 and NTRK2 genes, which have therapeutic potential. We also found that neither human immunodeficiency virus nor Epstein-Barr virus infection influences gene expression profiles linked to PI3K and MAPK signaling in PBL. These findings could lead to adapting targeted therapies developed for DLBCL to address the specific needs of PBL patients better and contribute to developing novel, targeted therapeutic strategies to improve patient outcomes.

Plasmablastic Lymphoma: Past, Present, and Future.

Plasmablastic Lymphoma is a rare large B-cell lymphoma with unique immunohistochemical and morphological features. It was most commonly associated with HIV infection; however, it's now seen in other immunosuppressed states like autoimmune conditions, post-transplant settings, and even in elderly immunocompetent individuals. Although rare, it is an aggressive lymphoma with unfavorable outcomes. The aim of this manuscript is to have an in-depth review of the current knowledge of epidemiology, pathophysiology, prognostic markers, and treatment approaches currently in use and in clinical trials for this challenging disease.

Case Report: Conjunctival Chemosis as a Presenting Sign of Plasmablastic Lymphoma in an HIV-negative Patient.

SIGNIFICANCE: Plasmablastic lymphoma (PBL) involving the ocular adnexa, although reported in the literature, is a rare clinical entity, especially when found in an immunocompetent patient. Understanding the clinical presentation can aid eye care practitioners in seeking timely diagnosis to avoid further delays in the treatment of this disease. PURPOSE: This study aimed to report orbital PBL in an HIV-negative patient and discuss the presenting clinical signs, symptoms, and other diagnostic findings for the proper treatment and management of this condition. CASE REPORT: A 79-year-old White male presented to our clinic for a second opinion for the evaluation of a swollen, mildly painful right eye for 2 months. The patient also complained of intermittent tenderness of the right frontal and paranasal sinuses. The initial diagnosis was preseptal cellulitis. Best-corrected visual acuity was 20/40 in the right eye and 20/30 in the left eye. A thorough comparison of the globe revealed subtle proptosis in the right eye. Slit-lamp evaluation revealed severe conjunctival chemosis, which was greatest in the inferotemporal quadrant, and diffuse right inferior eyelid edema. Globe proptosis was quantified via Luedde Exophthalmometer (Gulden Ophthalmics, Elkins Park, PA). Exophthalmometry values were 22 mm in the right eye and 20 mm in the left eye, suggesting mild proptosis of the right eye. MRI of the brain and orbits revealed an expansile lesion in the right maxillary, ethmoid, and paranasal sinuses. The mass also extended into the anterior cranial fossa and the right orbit. Needle biopsy and immunohistochemical analysis confirmed a diagnosis of PBL. The patient chose to discontinue chemotherapy owing to adverse systemic effects and died of the disease 36 months after the initial diagnosis. CONCLUSIONS: Unilateral conjunctival chemosis with no improvement or resolution warrants further investigation and workup. Eye care practitioners play a crucial role in the diagnosis and management of these patients in close collaboration with pathology, hematology, and oncology specialists.