Subclassification of lymphoproliferative disorders in serous effusions

The urgency of Burkitt lymphoma diagnosis in fluid cytology-A tertiary care experience

BACKGROUND

Burkitt lymphoma (BL) is an aggressive high-grade B-cell non-Hodgkin lymphoma commonly diagnosed in young age and is known to involve extra nodal sites. But the involvement of body fluids by BL is an uncommon presentation. Rapid diagnosis of BL is vital to prevent complications like tumour lysis syndrome. Cytological examination of body fluids continues to be an indispensable tool for rapid diagnosis of BL.

OBJECTIVES

In this study, we aim to study the clinical, cytomorphological and immunophenotypic characteristics of BL involving serous effusions and other fluids.

MATERIALS AND METHODS

In this retrospective study, 17 cases reported as BL in fluid cytology from 2016 to 2022 were collected and reviewed. We performed a comprehensive analysis of the clinical data, cytomorphological features, immunophenotyping data along with the haematological workup of these cases. We have also compared with the histopathological diagnosis for those cases where biopsy was available.

RESULTS

BL more commonly involved ascitic fluid (52%), followed by pleural fluid (4 cases) and cerebrospinal fluid (CSF; 4 cases). Primary diagnosis of BL in fluid was done in 88% of the cases. Bone marrow involvement was noted in two cases. Cytological smears showed discrete monomorphous population of medium-sized atypical lymphoid cells with frequent apoptotic bodies. Classic cytoplasmic punched out vacuoles were observed in 88% of the cases. Immunophenotyping data was available for 12 cases in which tumour cells showed positivity for CD20 (100%), CD10 (4 of 7 cases), BCL6 (3 of 5 cases) and cMYC (7 of 7 cases-100%) and were negative for Terminal deoxynucleotidyl transferase (TdT) (11 of 11 cases). Mean Ki67 labelling index was 95%. Histopathological diagnosis was available for 9 cases, and there was 100% agreement between cytological and histopathological diagnosis in 7 cases.

CONCLUSION

Precise diagnosis of BL can be rendered in body fluids by identification of classic cytomorphological features and by performing supportive ancillary tests in fluids for immunophenotyping.

A Simple and Practical Guide for Triaging Lymphocyte-rich Effusions for Ancillary Studies

Lymphocyte-rich effusions of the body cavities may represent a reactive/benign condition, primary effusion lymphoma, or systemic lymphoma with secondary malignant effusion, either as initial presentation or as a late complication. Cytomorphologic examination is essential and fundamental for diagnosis and may provide important clues to the nature of diseases. However, based on morphology alone, cytologic diagnosis of lymphocyte-rich effusions could be very challenging, particularly when the lymphocytes are small. Cytologists/cytopathologists might be uncertain when a lymphocyte-rich effusion specimen warrants a comprehensive hematopathologic workup. Herein we present a simple and practical algorithmic approach. On the basis of the cytomorphology of lymphocytes (small vs. large cells), presence or absence of cellular atypia, and clinical information (an earlier history or current lymphoma), the lymphocyte-rich effusion samples could be triaged for ancillary studies including immunophenotyping and molecular assays if indicated. Incorporation of cytomorphology, correlation with clinical information, and appropriate application of various ancillary techniques is mandatory for a correct diagnosis of lymphocyte-rich effusion specimens.

Lymphoreticular malignancies in serous effusions: Cytomorphologic, flow cytometric and immunocytochemical analysis

INTRODUCTION

Involvement of body fluids by lymphoreticular malignancies (LRM) is rare and often associated with poor prognosis and decreased overall survival. The present study was conducted to analyze the characteristic cytomorphologic, flow cytometric and immunocytochemical features of LRMs in serous effusions.

MATERIALS AND METHODS

This was a three-year retrospective study. A total of 218 effusion samples, reported as involved by lymphoreticular malignancies, on cytology, were reviewed. All the cases wherein the cytological diagnosis was confirmed by flow cytometric (FCM) and/or immunocytochemical (ICC) studies were retrieved and studied in detail. FCM and/or ICC were performed in a total of 51/218(23.4%) samples, including 30 pleural (58.8%), 18 peritoneal (35.3%), and 3 pericardial fluid (5.9%) samples.

RESULTS

The cytomorphologic diagnoses included infiltration by non-Hodgkin lymphoma (NHL;n = 27), infiltration by LRM (n = 19), infiltration by chronic lymphocytic leukemia (CLL;n = 2), Hodgkin's lymphoma (HL;n = 1) and suggestive of infiltration by LRM (n = 2). FCM and/or ICC confirmed the diagnoses as infiltration by T-cell lymphoblastic lymphoma in 18; mature B-cell NHL in 10; Burkitt lymphoma in 7; diffuse large B-cell lymphoma in 4; follicular lymphoma, T- cell NHL and CLL in 2 samples each and hairy cell leukemia, plasmablastic lymphoma and HL in 1 sample each. 94.1% concordance was noted between the initial and final cytologic diagnosis.

CONCLUSIONS

Involvement of body fluids and effusions by LRMs, though rare, carries an immense prognostic significance and hence the prompt detection is crucial. Detection of these malignancies by cytologic examination of effusions is challenging yet potentially useful and the least invasive method available to establish an early diagnosis.

Lymphomatous effusion of monomorphic epitheliotropic intestinal T-cell lymphoma is characterized by azurophilic granules and is a dismal sign: Report of two new cases with literature review

Lymphoma involving serous effusion is uncommon. The diagnosis of effusion lymphoma may be challenging, particularly when the lymphoid cells are small to medium-sized, which would be difficult for differentiating reactive effusions from low grade lymphomas. Monomorphic epitheliotropic intestinal T-cell lymphoma (MEITL) is an uncommon type of aggressive intestinal T cell lymphoma with a median survival of 7 months. MEITL rarely disseminates to the body cavities. To date, there are only three reported cases of MEITL with malignant effusion. Here we report two additional cases of MEITL with lymphoma cells involving the pleural effusion and the ascites, respectively. Review of the three literature cases and our two new cases of MEITL with malignant effusion, cytoplasmic azurophilic granules were identified in both the two cases with Liu stain. The median survival time was 1.5 months after the occurrence of malignant effusion, even shorter than the median survival in patients with MEITL. Although the case number is small, malignant effusion seems to be a poor prognostic factor of MEITL.

Serous Effusions Diagnostic Accuracy for Hematopoietic Malignancies: A Cyto-Histological Correlation

Background: The aim of this study was to establish the liability of cytological diagnostic and, along with ancillary techniques, to sub-classify hematopoietic malignancies in serous effusions.

Methods: We retrospectively reviewed the serous effusions of hematopoietic malignancies over an 11-year period, along with ancillary studies, clinical and histological data. We compared cytological along with histological diagnosis to evaluate the value of cytology itself. Furthermore, the discrepant cases were reviewed.

Results: In this study, a total of 242 cases were identified as hematopoietic malignancies. Ancillary technologies were performed: in 24 cases FCM, 242 cases ICC, 35 cases ISH, 81 cases PCR and 10 cases FISH. Cyto-histological correlation was available for 122 cases. The subtyping of hematopoietic malignancies was achieved using cytological material in 65/122 cases (53.3%). Of the 65 cases, T-Acute lymphoblastic leukemia/lymphoma (22.1%) was the leading subtype, followed by Burkitt lymphoma (5.7%), plasmacytoma (5.7%). Cyto-histological correlation showed a 100% concordant rate of diagnosis for hematopoietic malignancies and a high degree of agreement on sub-classification (51.6%). In this regard, T-acute lymphoblastic leukemia/lymphoma, plasmacytoma, extranodal NK/T-cell lymphoma, nasal type, anaplastic large cell lymphoma, myeloid sarcoma, and follicular lymphoma showed the highest degree of agreement (100%). The sub-classification on cytology was achieved in 53 out of the remaining 120 cases without histological diagnosis (44.2%). T-acute lymphoblastic leukemia/lymphoma (20.8%) was again the most frequently encountered subtype, followed by plasmacytoma (5.8%) and Burkitt lymphoma (4.2%).

Conclusions: This large series study provided evidence that combining cytology and ancillary studies enabled the accurate serous effusions cytological diagnoses and subsequent sub-classification for the described malignancies.

The cytopathological spectrum of lymphomas in effusions in a tertiary center in Taiwan

Lymphomas presenting in effusions could either be primary or secondary, with very limited data from Taiwan.

METHODS

We retrospectively reviewed effusion lymphomas from our archives in a tertiary center from July 2011 to June 2019.

RESULTS

We identified 59 specimens from 43 patients, including 7 cases with primary effusion lymphoma (PEL) and 36, secondary effusion involvement. Half of the secondary cases presented concurrently with effusion lymphoma, while the remaining half-experienced effusion lymphoma during disease progression. All patients with PELs were males with a median age of 77 and presented with massive pleural effusion. None was HIV-related. Two (29%) PEL cases were positive for human herpes virus 8 (HHV8). The only case with plasmablastic phenotype in the PEL group was positive for both HHV8 and EBV. Four patients died shortly after diagnosis; while the remaining three were alive at the last follow-up (two at 13 months and one at 99 months). Of the secondary cases, diffuse large B-cell lymphoma/high grade B-cell lymphoma was the most common (n = 16, 44%), followed by mantle cell lymphoma (n = 5, 14%). Only 8 cases (22%) were T-cell neoplasms. Prognosis for patients with secondary effusion involvement was dismal, with 1- and 2-year overall survival rates at 17% and 8%, respectively.

CONCLUSION

We found a wide cytopathological spectrum of effusion lymphoma in Taiwan. Most of our PEL cases were distinct from that defined in the World Health Organization scheme by a B-cell phenotype, HHV8-negativity, and absence of immunodeficiency. As compared to PEL cases, the prognosis of those with secondary involvement was extremely poor.

Clinical and laboratory characteristics of lymphoid neoplasms in serous effusions: a single centre experience in China

BACKGROUND

Lymphoid neoplasms in serous effusions are uncommon, and the details of lymphoid neoplasms in serous effusions from China are still unclear.

METHODS

Between January 2004 and December 2019, all patients with lymphoid neoplasms in pleural effusions, ascites, and pericardial effusions in our hospital, were reviewed.

RESULTS

A total of 65 patients with lymphoid neoplasms were collected during this period. The top three neoplasms were diffuse large B-cell lymphoma (DLBCL) (n = 20, 30.7%), myeloma (n = 13, 20.0%), and T-lymphoblastic lymphoma (n = 7, 10.8%). In pleural effusions involving DLBCL, the cytomorphology of DLBCL cells was diverse; most pleural effusions were present during the tumor course (92.9%); bilateral pleural effusions were predominant (57.2%); and the median survival time was only 1.23 months after the effusion. In pleural effusions involving myeloma, 90.9% of cases (10/11) had a high ratio (> 1.0) of immature to mature plasma cells; paraprotein types of IgA (36.4%) and light chain λ (36.4%) were the most frequently found; bilateral pleural effusions were easily found (n = 10, 90.9%); and the median survival time was only 1.4 months after the effusion.

CONCLUSION

In pleural effusions involving DLBCL, most of our patients with effusions are present during the tumor course, and bilateral pleural effusions are predominant. In pleural effusions involving myeloma, the paraprotein types of IgA and light chain λ are the most frequently found, and it has a high ratio of immature to mature plasma cells in pleural effusions.

Triaging of pleural effusion cytology specimens for ancillary flow cytometric analysis

INTRODUCTION

There are no established criteria in selecting pleural effusion (PE) specimens for flow cytometric analysis (FCA). FCA on effusion specimens may be ordered by a clinician or a cytopathologist. In an effort to improve lab test utilization, this retrospective study aims to identify characteristics of PE specimens on which the addition of FCA has high diagnostic yield.

MATERIALS AND METHODS

We identified consecutive cases of PE cytology specimens on which FCA was performed over a 5-year period (2014-2019). Patient demographic data and history, FCA diagnosis, cytologic diagnosis, cellular quantity and composition, and peripheral blood cell counts were collected. Chi-square, Mann-Whitney U, and t tests were used when appropriate with a significance level of P < 0.05.

RESULTS

We identified 164 FCA cases corresponding to 142 patients (age: 19-90 years; male:female 2:1). The majority of cases had no abnormality by cytologic examination, whereas others were obviously malignant due to non-hematologic malignancy. Most (119 of 164, 73%) had negative immunophenotypic studies by FCA. Forty-five of 164 (27%) FCA cases were positive for a monoclonal myeloid or lymphoid population. Clinicopathologic features associated with positive FCA results included a history of hematologic malignancy, peripheral blood lymphocytes of ≥20%, the presence of a monomorphic lymphoid population, large atypical cells, and mitoses.

CONCLUSIONS

This study identifies features that are associated with positive FCA in PE cytology specimens. Using these features by cytopathologists to order FCA on PE specimens as a reflex test would significantly reduce unnecessary testing and improve FCA utilization.

A Proposal for the Performance, Classification, and Reporting of Lymph Node Fine-Needle Aspiration Cytopathology: The Sydney System

BACKGROUND

The evaluation of lymph nodes (LN) by fine-needle aspiration cytology (FNAC) is routinely used in many institutions but it is not uniformly accepted mainly because of the lack of guidelines and a cytopathological diagnostic classification. A committee of cytopathologists has developed a system of performance, classification, and reporting for LN-FNAC.

METHODS

The committee members prepared a document that has circulated among them five times; the final text has been approved by all the participants. It is based on a review of the international literature and on the expertise of the members. The system integrates clinical and imaging data with cytopathological features and ancillary techniques. The project has received the endorsement and patronage of the International Academy of Cytology and the European Federation of the Cytology Societies.

RESULTS

Clinical, imaging, and serological data of lymphadenopathies, indications for LN-FNAC, technical procedures, and ancillary techniques are evaluated with specific recommendations. The reporting system includes two diagnostic levels. The first should provide basic diagnostic information and includes five categories: inadequate/insufficient, benign, atypical lymphoid cells of undetermined/uncertain significance, suspicious, and malignant. For each category, specific recommendations are provided. The second diagnostic level, when achievable, should produce the identification of specific benign or malignant entities and additional information by utilizing ancillary testing.

CONCLUSION

The authors believe that the introduction of this system for performing and reporting LN-FNAC may improve the quality of the procedure, the report, and the communication between cytopathologists and the clinicians. This system may lead to a greater acceptance and utilization of LN-FNAC and to a better interdisciplinary understanding of the results of this procedure.

Diagnostic role of cytology in serous effusions of patients with hematologic malignancies

BACKGROUND

We investigated serous effusions occurring during the course of an already known hematologic neoplasia or as a first manifestation of it. We correlated cytology results with flow cytometry results, when available. In the absence of flow cytometry, our correlation was based on clinical follow up information obtained retrospectively. We evaluated our results in relation to the data of the literature and we considered some new suggestions for the improvement of cytology service.

METHODS

Serous effusions in hematologic patients were retrieved from the files of the Department of Cytology, Laiko Hospital, for a period of 2 years. All patients had enrolled either a previous hematologic history, or a suspicious clinical and imaging status. Seventy-three serous effusions were included. Cytology reports consisting of morphology and immunocytochemistry assessment were correlated to flow cytometry results and, occasionally, to clinical follow-up.

RESULTS

In the group of patients with previous history, sensitivity was 82.76%, positive predictive value was 100%, specificity 100%, and negative predictive value was 58.33%. In the group of patients without previous history, sensitivity and positive predictive value were both 91%, whereas specificity and negative predictive value could not be estimated.

CONCLUSION

We provide evidence that the diagnostic accuracy of cytology with the adjunct of immunocytochemistry is high compared to flow cytometry for detecting hematologic malignancies. In order to improve clinical performance, it is suggested that a cytology triage of serous effusions in all patients with hematologic malignancy must be implemented.

Updates in Effusion Cytology

Effusion cytology plays multiple roles in the management of benign and malignant disease, from primary diagnosis to tissue allocation for ancillary diagnostic studies and biomarker testing of therapeutic targets. This article summarizes recent advances in pleural effusion cytology, with a focus on the practical application of immunohistochemical markers, cytogenetic techniques, flow cytometry, and molecular techniques for the diagnosis and management of primary and secondary neoplasms of the pleura.

Cytology and clinical features of myelomatous pleural effusion: Three case reports and a review of the literature

The purpose of this study was to report the clinical features, laboratory findings, and cytomorphology, and prognosis of three patients with myelomatous pleural effusion (MPE). The literature pertaining to MPE was reviewed. The three cases and literature review suggest that MPE is rare and often associated with a poor prognosis. The correct diagnosis depends on the aggressive clinical characteristics, laboratory findings, and chromosomal abnormalities, but routine pathological examination of the pleural effusion has low sensitivity. Cell blocks stained with hematoxylin & eosin and by immunohistochemistry revealed that abnormal proliferation of plasma cells and light chain restrictive expression in MPE may be helpful for improving the detection rate of MPE.

Preanalytic specimen triage: Smears, cell blocks, cytospin preparations, transport media, and cytobanking

With increasing requests for the evaluation of prognostic and predictive molecular biomarkers, great attention must be paid to the preanalytical issues regarding sample quality and DNA/RNA yield from all different types of cytological preparations. The objectives of this review were: 1) to provide an update regarding the importance of specimen triage as well as specimen handling and collection; 2) to discuss the different cell preparations that can be used for molecular testing, their advantages and limitations; and 3) to highlight the strategies for biobanking cytology samples. Good-quality DNA/RNA can be harvested from fresh cells in cell suspensions, formalin-fixed paraffin-embedded cell blocks, archival stained smears, archival unstained cytospin preparations, liquid-based cytology slides, FTA cards, and cryopreserved cells. In contrast to formalin-fixed paraffin-embedded tissue specimens (small biopsies and surgical resections), the multitude of types of sample preparations as well as the diversity in sample collection and processing procedures make cytology an ideal specimen for most genomic platforms, with less DNA and RNA degradation and a purer sample, usually with a higher concentration of tumor cells. The broad incorporation of cytological specimens into clinical practice. A should increase the number of samples potentially available for molecular tests and avoid repeat invasive procedures for tissue procurement, thereby increasing patient safety. In this context, it is of utmost importance that cytopathologists become familiar with the variables that can affect test results and embrace the goal of excellence in sample quality. Cancer Cytopathol 2017;125(6 suppl):455-64. © 2017 American Cancer Society.

Utility of flow cytometry analysis for pleural and peritoneal fluids

INTRODUCTION

Pleural and peritoneal/ascites fluid samples with many lymphocytes are commonly received in the cytology laboratory. It is often difficult to distinguish reactive lymphocytes from hematopoietic malignancy based on morphology alone, however. Flow cytometry can be a useful adjunct in body fluids, although literature on this subject is limited.

MATERIALS AND METHODS

This study is a single-institution 5-year retrospective review of 377 fluid samples from 341 patients with corresponding flow cytometry analysis. The cytologic findings were correlated with the flow cytometry results and clinical data, as available.

RESULTS

Of 4158 pleural fluids received over 5 years, 325 (7.8%) had corresponding flow cytometry analysis. Of these 325 samples, 57 (17.5%) were positive for hematopoietic malignancy by flow cytometry. Of the positive cases, only 24 (8.7%) represented a new diagnosis of hematopoietic malignancy (ie, did not have a known history). Of 3020 peritoneal/ascites fluids received over 5 years, 52 (2%) had corresponding flow cytometry. Of these, 8 were positive for hematopoietic malignancy, and only 2 represented a presumed new diagnosis.

CONCLUSIONS

Routine flow cytometry analysis for pleural and peritoneal/ascitic fluids is of limited utility, with only rare cases positive for hematopoietic malignancy without a known history. Of these cases, many had atypical cells that suggested a positive diagnosis. Conversely, in cases with a known history, about 75% were positive for hematopoietic malignancy. Our study suggests that the utility of flow cytometry for pleural and peritoneal/ascitic fluids is limited, and should be used sparingly in cases without atypical cytologic features, high clinical suspicion, or known history.

Flow Cytometry and Effusions in Lymphoproliferative Processes and Other Hematologic Neoplasias

Cytopathologists are regularly confronted with lymphocyte-rich effusions, and the definite decision of whether the lymphocytosis is of a purely reactive nature or a presentation of an indolent lymphoma may be an extremely difficult one based on microscopy alone. Flow cytometry (FC) offers many advantages in terms of its application in body cavity fluids, and it has proven to be very useful both in the setting of a known disease and for new lymphoma diagnoses. In this paper, the studies published in recent years dealing with the applications of FC in body cavity effusions in the context of hematologic neoplasia are reviewed, stressing the integrative diagnostic approach. The incorporation of microscopical, immunophenotypical, and molecular findings from examinations of the cellular content of effusions and the interpretation of results in relation to the current WHO classification of hematolymphoid malignancies give cytopathologists new perspectives on advanced and clinically highly relevant diagnostics.

Role of Epstein-Barr virus status and immunophenotypic studies in the evaluation of exfoliative cytology specimens from patients with post-transplant lymphoproliferative disorders

BACKGROUND

Post-transplant lymphoproliferative disorders (PTLDs) are well characterized in tissue sections, but their evaluation in exfoliative cytology specimens is limited. This study reports a 25-year experience with PTLDs in exfoliative cytology specimens.

METHODS

All solid organ or allogeneic stem cell transplant recipients with PTLDs and exfoliative cytology specimens from 1987 to 2011 were identified. The cytomorphology, Epstein-Barr virus (EBV) status, flow cytometry, immunohistochemistry, and molecular studies were reviewed from all exfoliative cytology specimens previously diagnosed as atypical lymphoid proliferations or PTLDs.

RESULTS

A total of 55 patients (age range, 1-72 years) with PTLDs had 434 exfoliative cytology specimens. Thirty-six of the 55 patients (65%) had 54 specimens with abnormal lymphoid proliferations (12% of the specimens), and 26 of these patients had 37 specimens available for review (15 cerebrospinal fluid specimens, 12 peritoneal fluid specimens, 9 pleural fluid specimens, and 1 bronchoalveolar lavage fluid specimen). Thirty percent of the reviewed cytology specimens were diagnostic of PTLDs, including 8 cases of monomorphic post-transplant lymphoproliferative disorder (M-PTLD) with abnormal B/T-cell populations identified with flow cytometry/immunohistochemistry and 3 EBV-positive specimens with a differential diagnosis of polymorphic PTLD versus M-PTLD. All cases diagnostic of a PTLD had 1 to 3 ancillary studies performed. Forty percent of the cytology specimens (15 of 37) were suspicious for a PTLD, but ancillary studies were performed for only a third of them, and they did not support a definitive diagnosis of a PTLD. Thirty percent of the cytology specimens (11 of 37) appeared reactive, but they lacked sufficient ancillary studies to exclude a PTLD.

CONCLUSIONS

Atypical lymphoid proliferations are common in exfoliative cytology specimens from patients with PTLDs, and they require ancillary studies at least including immunophenotyping and EBV evaluations for a definitive diagnosis. Cancer Cytopathol 2016;124:425-35. © 2016 American Cancer Society.

Malignant effusions correlate with poorer prognosis in patients with diffuse large B-cell lymphoma

OBJECTIVES

Serous effusions are a common manifestation of diffuse large B-cell lymphoma (DLBCL). However, their prognostic significance is controversial.

METHODS

We searched for consecutive patients who had DLBCL with effusions from 1999 through 2007. Primary effusion lymphoma was excluded. The presence of tumor cells in effusions (malignant effusions) was determined by cytology supplemented by flow cytometry, cell blocks with special studies, polymerase chain reaction for clonality, or conventional cytogenetics.

RESULTS

Forty-one (18.4%) patients had effusions, with 24 (58.5%) developing at diagnosis and 17 (41.5%) during tumor course. Nineteen patients (46.0%) had malignant effusions, with six (31.6%) from local extension and 13 (68.4%) through wide dissemination. Interestingly, malignant effusion correlated with a high International Prognostic Index (IPI) score (r = 0.490, P = .002) and high tumor stage (r = 0.342, P = .031) and was a poor prognosticator (P < .001, log-rank test), even worse than stage IV disease (P = .036). In the multivariate analysis, malignant effusion (P = .056) and supportive care (P = .014) retained significance and were more powerful than IPI score and stage.

CONCLUSIONS

Patients who have DLBCL with lymphomatous effusions have a poor prognosis and should be treated as having stage IV disease. The analysis of effusions for tumor cells would be a useful addition to the routine workup.

Extraoral plasmablastic lymphoma detected using ascitic fluid cytology and flow cytometry: a case report with a review of the literature

BACKGROUND

Plasmablastic lymphoma (PL) is a relatively new category of lymphoma, which has been considered to be found predominantly in the oral cavity and has a strong association with HIV.

CASE

We report a case of extraoral/mesenteric PL detected using cytological examination of ascitic fluid assisted by flow cytometric (FC) analysis. The cells were positive for CD38, CD138, CD10, CD45 and CD56 and negative for CD3, CD19, CD20 and CD79a, with cytoplasmic lambda light-chain restriction. We also reviewed 67 cases of extraoral PL from the available literature and found them to be less often associated with HIV (than oral PL), occurring mostly in males aged 30-60 years, with the most common extraoral site being the anorectal region.

CONCLUSION

A high index of suspicion at the level of the cytopathologist is imperative for identifying lymphoma cells in a body fluid. A rare entity like PL can also be diagnosed on cytology assisted by ancillary techniques (like FC), without the need for a biopsy. We also suggest that the minimum panel to diagnose PLs should include CD138, MUM-1, Ki-67, ALK-1, CD3, immunoglobulin light-chains, CD20 and PAX5.