Diagnosis of deep‐seated lymphomas by endoscopic ultrasound‐guided fine needle aspiration combined with flow cytometry

A. Stacchini, P. Carucci, D. Pacchioni, G. Accinelli, A. Demurtas, S. Aliberti, M. Bosco, M. Bruno, A. Balbo Mussetto, M. Rizzetto, G. Bussolati and C. De Angelis
Diagnosis of deep‐seated lymphomas by endoscopic ultrasound‐guided fine needle aspiration combined with flow cytometry Objective: Although endoscopic ultrasound combined with fine needle aspiration (EUS‐FNA) is rapidly becoming the preferred diagnostic approach for the sampling and diagnosis of gastrointestinal and mediastinal malignancies, there are limited data as to its use in the diagnosis of lymphoproliferative disorders. Therefore, we carried out a retrospective evaluation of the performance of EUS‐guided FNA combined with flow cytometry (FC) as a tool to improve overall sensitivity and specificity in the diagnosis of lymphoma. Methods: Of 1560 patients having EUS‐guided FNA during the period of the study, a total of 56 patients were evaluated by cytology with FC after EUS‐FNA. There was adequate material to perform FC analysis for all but one case. Results: EUS‐FNA‐FC gave a diagnosis of lymphoma in 11 cases and of reactive lymphadenopathy in 20. A specific histological type was defined by FC alone in eight cases. The remaining cases were diagnosed later by cytology and cell block sections: 13 carcinomas, nine granulomatous lymphadenopathies and one mediastinal extramedullary haematopoiesis. One case was considered only suspicious for lymphoma on cytology and FC but was not confirmed on molecular analysis and one had insufficient material for FC. Conclusions: Our results show that a combination of EUS‐FNA‐FC is a feasible and highly accurate method, which may be used for the diagnosis and subtyping of deep‐seated lymphoma, providing a significant improvement to cytomorphology alone both for diagnosis and treatment planning, as long as immunocytochemistry is available for non‐lymphoma cases.     

Role of endoscopic ultrasound‐guided‐fine needle aspiration biopsy in the diagnosis of lymphoma of the pancreas: A clinicopathological study of nine cases

Objective

Endoscopic ultrasound‐guided‐fine needle aspiration (EUS‐FNA) is an established first‐line procedure in the management of solid and cystic pancreatic masses. Lymphoma is an uncommon diagnosis in EUS‐FNA of the pancreas, and it is more common for such a diagnosis to be because of secondary involvement of the pancreas by a lymphoproliferative disorder than for this to represent isolated primary pancreatic lymphoma (PPL). We present the clinical, EUS and cytological features of these lesions.

Material and methods

After obtaining approval from our Institutional Review Board (IRB), nine cases of lymphoma diagnosed on EUS‐FNA at a tertiary care cancer centre over a period of 8 years from 2008 to 2016 were retrieved from our endoscopy and pathology archives. Rapid onsite evaluation (ROSE) was carried out by a trained cytopathologist in all these cases. Cell blocks were available in seven cases, and immunophenotyping was performed on cell blocks using the immunoperoxidase method. Flow cytometry was performed in two cases.

Results

The most frequent site of involvement was the head of the pancreas (n=5, 55.6%). Four out of nine cases were diagnosed as PPL (44.4%). Five cases were diagnosed as lymphoma secondarily involving the pancreas (55.6%). The most frequent diagnosis was diffuse large B‐cell lymphoma (n=6, 66.7%), followed by Hodgkin's lymphoma (n=2, 22.2%) and peripheral T‐cell lymphoma (n=1, 11.1%).

Conclusion

EUS‐FNA in experienced hands is a valuable diagnostic modality, in conjunction with ROSE, immunohistochemistry and flow cytometry, in the diagnosis and sub‐typing of both primary and secondary pancreatic lymphoma.     

NK cell lymphoma, nasal type, with massive lung involvement: a case report

Extranodal NK/T cell lymphoma, nasal type, is an Epstein–Barr virus-associated lymphoma that most commonly involves the nasal cavity and upper respiratory tract. Lung involvement by NK/T cell lymphoma is rare and seldom reported in the literature. We describe the unusual case of a 41-year-old male with NK cell lymphoma, nasal type, who presented with massive secondary lung involvement 2.5 years after the detection of a retroperitoneal mass. The diagnosis was made by open lung biopsy. Despite aggressive treatment, the patient died shortly after the initiation of therapy. Lung involvement by NK/T cell lymphoma occurs most commonly as part of widely disseminated disease and carries a poor prognosis for the patient. Novel agents and innovative therapies need to be developed for this aggressive lymphoma.     

Cytodiagnosis of lymphoid proliferations by fine needle aspiration biopsy. Adjunctive value of flow cytometry

OBJECTIVE: To determine the accuracy of fine needle aspiration biopsy (FNAB) complemented by flow cytometry (FC) for the diagnosis of reactive and neoplastic lymphoid proliferations and subclassification of malignant lymphomas. STUDY DESIGN: Forty-one FNABs of lymphoid lesions on which FC had been performed were evaluated retrospectively. All cases were correlated with histology or clinical follow-up. RESULTS: Twelve FNABs were diagnosed as reactive. Eleven of the 12 were confirmed as reactive on follow-up. One was a case of posttransplant lymphoproliferative disorder. Twenty-five FNABs diagnosed as lymphoma were confirmed by histology. In 22 of these 25 cases, there was 100% correlation between the subclassification given on FNAB with FC and that given on histology. Two of the remaining cases, which were correctly called follicular center cell lymphoma, showed discrepancies in grading. One case called Hodgkin's disease on FNAB was T-cell lymphoma on histology. Of four FNABs given an inconclusive diagnosis, two were lymphoma on follow-up, and two were reactive. CONCLUSION: FNAB examination, when it includes immunophenotyping by FC, is a useful technique for distinguishing reactive lymphoid proliferations from malignant lymphomas and for the subclassification of lymphomas.     

Combined cytomorphologic and immunophenotypic analysis in the diagnostic workup of lymphomatous effusions

OBJECTIVE: To analyze the results of cytomorphology and immunophenotyping in 54 patients with lymphomatous effusions. STUDY DESIGN: We report the results of cytomorphology and immunophenotyping in 54 patients with lymphomatous effusions. Twenty-three of the 54 had a previous diagnosis of NHL. In the remaining 31 patients, lymphomatous involvement was clinically suspected. RESULTS: Thirty-three lymphomatous effusions were positive for involvement by NHL. Twenty-one of these 33 patients (64%) had a previous diagnosis of NHL. Of the remaining 12 patients with newly diagnosed NHL, 11 had high grade lymphoma, and one had follicular center lymphoma. Twenty effusions were considered to be reactive; only two of these patients had NHL. One effusion revealed involvement by a previously unknown carcinoma. We observed seven false negative results if only one of both methods was considered. A high grade NHL was not diagnosed by immunophenotyping in one case, and six cases of low grade NHL could not be detected by cytomorphology. The combined strategy of cytomorphology and immunophenotyping had a sensitivity of 100% and specificity of 100% in our study, confirmed by follow-up studies. CONCLUSION: Both methods have shown difficulties in the examination of lymphomatous effusions. Cytomorphology has problems distinguishing reactive effusions from low grade NHL. The detection of high grade NHL by immunophenotyping is difficult. However, both methods together offer the advantage of dual staining ability and are most helpful in distinguishing clonal lymphomatous from reactive effusions.     

Diagnosis of cervical thymoma by fine needle aspiration biopsy with flow cytometry. A case report

BACKGROUND: Cervical thymoma is a rare entity. To our knowledge, this is the 20th reported case of cervical thymoma and the fourth case of fine needle aspiration biopsy (FNAB) of this entity. To our knowledge, this is the only case in which cervical thymoma was a diagnostic consideration at the time of the FNAB diagnosis. The diagnosis was rendered because, unlike in previous cases, flow cytometric immunophenotyping was performed. CASE: A 46-year-old, white female presented with what was clinically thought to be a left thyroid nodule. The patient underwent FNAB at an outside institution, and the diagnosis of "possible mixed lymphoma" was made by morphology alone. The patient was referred to our institution for repeat FNAB. Based upon the cytologic findings (cells with lymphoid morphology), flow cytometry was performed, and a diagnosis of cervical thymoma (versus ectopic thymic tissue) was based upon flow cytometry findings combined with morphology. CONCLUSION: When FNAB of a cervical mass, particularly one clinically thought to be a thyroid nodule, shows lymphoid cells without thyroid follicular cells, immunophenotyping may be extremely helpful in arriving at the correct diagnosis.     

Multilobated large B-cell lymphoma diagnosed cytologically. A case report.

BACKGROUND: Fine needle aspiration (FNA) biopsy can be used to reliably classify most conditions involving lymph nodes or, at least, significantly reduce the differential diagnosis. CASE: A 70-year-old male presented with an ulcerated mass arising from the left tonsillar fossa and involving the anterior and posterior pillars. A biopsy of the tonsillar mass performed at an outside hospital was interpreted as a large cell undifferentiated carcinoma. Subsequently the patient developed systemic lymphadenopathy. A bone scan showed intense uptake within the medial tibial plateau of the left knee. FNA biopsy of the right axillary mass was interpreted at University of Cincinnati Medical College as a large cell lymphoma, multilobated type. Histologic and immunohistochemical studies of the lymph node confirmed the presence of multilobated B-cell lymphoma. Lymphoma chemotherapy was initially successful but was discontinued due to toxicity. The patient died two months after the initial cytologic diagnosis of lymphoma. CONCLUSION: Multilobated lymphomas are an unusual variant of non-Hodgkin's lymphomas (mostly B-cell type). Cytology and immunocytochemistry are useful diagnostic procedures that can help to diagnose this relatively uncommon type of lymphoma and significantly reduce the possibility of misdiagnosis.     

Fine needle aspiration cytology of granulomatous cryptococcosis of the lung

A cryptococcal infection was diagnosed in a patient with a history of immunoblastic non-Hodgkin's lymphoma by fine needle aspiration (FNA) cytology of a pulmonary nodule. This case illustrates that granulomatous inflammation can be appreciated by FNA cytology and, when seen, should result in a search for the specific organism. This case also reemphasizes the value of FNA cytology in the management and follow-up of patients with malignancy or those being treated with chemotherapy.     

Fine needle aspiration cytology of tuberculosis of the lumbar vertebrae (Pott's disease)

The cytomorphologic features of tuberculosis of the lumbar vertebra having a granulomatous pattern diagnosed by fine needle aspiration (FNA) biopsy are reported in a 72-year-old woman with a prior history of malignant lymphoma treated by chemotherapy. Cytologic examination revealed microtissue fragments of cohesive cells, including epithelioid histiocytes and scattered, multinucleated Langhans-type giant cells. This is believed to be the first reported case of vertebral tuberculosis (Pott's disease) diagnosed by FNA cytology and confirmed by culture of the aspirate material. This case illustrates the value of FNA cytology in the diagnosis of nonneoplastic skeletal lesions and confirms the value of FNA biopsy the early detection of infectious processes in patients with malignancy.     

Primary pleuropulmonary synovial sarcoma diagnosed by fine needle aspiration with cytogenetic confirmation: a case report

BACKGROUND: Pleuropulmonary synovial sarcomas (PPSSs) are rare neoplasins that have been well described in recent years, although there are only very infrequent reports within the cytology literature. Such lesions present a diagnostic challenge on fine needle aspiration (ENA) due to several factors, particularly when the aspirate material displays monophasic, small cell or poorly differentiated morphology. Immunoperoxidase studies on cell block material and confirmation with molecular cytogenetics are important tools to establish the diagnosis and determine appropriate therapy. We report a case of PPSS in a 27-year-old man diagnosed by computed tomography (CT)-guided FNA with confirmation by conventional and molecular cytogenetics. CASE: A 27-year-old man presented with several rapidly enlarging, pleura-based masses following a several-month history of recurrent hemopneumothorax. Previous surgical pathology on decorticated pleura was interpreted as a reactive mesothelial proliferation at another institution. Upon referral, CT-guided transthoracic FNA was performed. Smears revealed a highly cellular, dispersed "small round blue cell" neoplasm in a hemorrhagic background. The cytomorphology, in conjunction with a select immunoperoxidase panel, was diagnostic of PPSS. Conventional and molecular cytogenetics subsequently provided confirmation of the diagnosis. CONCLUSION: PPSSs are uncommon neoplasms seldom diagnosed by FNA, with only very rare reports in the cytology literature. Although their cytomorphology has been well described, monophasic tumors and other morphologic variants present a diagnostic challenge and may be difficult to discern from a variety of neoplastic and reactive/reparative processes. Emphasis should be placed upon securing material at the time of aspiration for immunoperoxidase studies (cell block or core biopsy). In equivocal cases, conventional and/or molecular cytogenetic studies may be needed.     

Fine needle aspiration of extramedullary myeloid cell tumor in myelodysplastic syndrome. A report of three cases.

BACKGROUND: Soft tissue tumors are rare in myelodysplastic syndrome (MDS), and the role of fine needle aspiration (FNA) cytology in their diagnosis has not been explored. CASES: Two patients with refractory anemia with excess blasts in transformation (RAEB-t) developed soft tissue swellings during the course of the illness. In a third patient, soft tissue swelling was a presenting feature. The swellings in all three cases were diagnosed as extramedullary myeloid cell tumor (EMT) on FNA and showed increased blasts (10-14%), dyspoietic changes, Auer rods and monocytosis. CONCLUSION: Soft tissue tumors appearing in MDS are likely to be EMTs. FNA is therefore particularly valuable in their diagnosis as morphology, cytochemistry, immunophenotyping and flow cytometric analysis of hematopoietic cells are best studied on aspirated material. We suggest that FNA be preferred over excisional biopsy for the diagnosis of soft tissue swellings in MDS.     

Hodgkin lymphoma: flow me?

Combining fine needle aspirate cytology with flow cytometry immunophenotyping for the rapid diagnosis of lymphoproliferative lesions is commonplace practice in many institutions. Yet, a definitive diagnosis of Hodgkin lymphoma in many cases remains elusive, requiring subsequent tissue biopsy confirmation. In this issue of CytoJournal, Hernandez et al explore the potential role of using the increased CD4/CD8 T-cell ratio in lymph node fine needle aspiration specimens as a specific feature in diagnosing Hodgkin lymphoma. CD4/CD8 T-cell ratio comparisons are made with cytomorphologic diagnoses of reactive, atypical, non-Hodgkin lymphoma, and Hodgkin lymphoma cases.     

Morphologic and immunocytochemical evaluation of 220 fine needle aspirates of malignant lymphoma and lymphoid hyperplasia

A total of 220 fine needle aspiration (FNA) specimens from 212 patients with clinically suspected or previously histologically confirmed lymphoma were evaluated by cytology in conjunction with immunophenotyping analysis of the aspirate; the results were compared with the histologic diagnosis made on previous or current accessions of lymph node or extranodal tissue. Smears of the aspirates were stained with the Diff-Quik and Papanicolaou stains while immunoperoxidase staining using antibodies against kappa and lambda immunoglobulin light chains and Leu-4 was routinely performed on Cytospin preparations. Where indicated, additional marker studies (including T-200, Leu-1, Leu-2a, Leu-3a + 3b, Leu-M1, B1, Leu-12, IgM, CALLA and TdT) were performed. For the non-Hodgkin's lymphomas, specimens were classified by the cytologic characteristics of the neoplastic cells according to the International Working Formulation scheme. The combination of cytologic smears and immunoperoxidase studies resulted in a diagnosis of lymphoma in 173 cases (79%). The remaining aspirates were interpreted as suspicious for lymphoma (7%), benign (10%) or inadequate for diagnosis (4%). Of the 15 suspicious aspirates, 5 proved to be Hodgkin's disease and 2 to be T-cell lymphoma by subsequent biopsy. The cause of failure in the nine inadequate aspirates were necrosis (3 cases), sclerosis (2 cases) and faulty technique (4 cases). In the cases that had concurrent tissue biopsies, no false-positive diagnoses were rendered. These results indicate that FNA used in association with immunocytochemistry is a reliable tool for establishing the diagnosis and classification of the majority of cases of lymphoma. Optimal immunoglobulin light-chain ratios for defining monoclonality in FNA specimens of B-cell lymphomas are proposed.     

Carcinoma and multiple lymphomas in one patient: establishing the diagnoses and analyzing risk factors

Multiple malignancies may occur in the same patient, and a few reports describe cases with multiple hematologic and non-hematologic neoplasms. We report the case of a patient who showed the sequential occurrence of four different lymphoid neoplasms together with a squamous cell carcinoma of the lung. A 62-year-old man with adenopathy was admitted to the hospital, and lymph node biopsy was positive for low-grade follicular lymphoma. He achieved a partial remission with chemotherapy. Two years later, a PET-CT scan showed a left hilar mass in the lung; biopsy showed a squamous cell carcinoma. Simultaneously, he was diagnosed with diffuse large B cell lymphoma in a neck lymph node; after chemo- and radiotherapy, he achieved a complete response. A restaging PET-CT scan 2 years later revealed a retroperitoneal nodule, and biopsy again showed a low-grade follicular lymphoma, while a biopsy of a cutaneous scalp lesion showed a CD30-positive peripheral T cell lymphoma. After some months, a liver biopsy and a right cervical lymph node biopsy showed a CD30-positive peripheral T cell lymphoma consistent with anaplastic lymphoma kinase-negative anaplastic large cell lymphoma. Flow cytometry and cytogenetic and molecular genetic analysis performed at diagnosis and during the patient’s follow-up confirmed the presence of two clonally distinct B cell lymphomas, while the two T cell neoplasms were confirmed to be clonally related. We discuss the relationship between multiple neoplasms occurring in the same patient and the various possible risk factors involved in their development.     

Cytomorphology and immunocytochemistry of fine needle aspirates from blastic non-Hodgkin's lymphomas

Fine needle aspirates from 54 consecutive patients with primary or recurrent blastic (high-grade malignant) non-Hodgkin's lymphomas (NHLs) were analyzed by cytomorphology and immunocytochemistry. The cytologic diagnoses induced follicular center-cell-derived (centroblastic or anaplastic centrocytic) lymphoma (31 cases), immunoblastic lymphoma (11 cases), lymphoblastic lymphoma (9 cases) and histiocytic lymphoma (3 cases). Immunocytochemistry showed a B-cell phenotype of the neoplastic lymphocytes in all lymphoblastic lymphomas, 29 follicle center-cell lymphomas and 4 immunoblastic lymphomas. Four of the immunoblastic lymphomas were of T-cell origin while one case was not evaluable due to necrosis. A histiocytic origin was confirmed in two of the three cases that had a cytologic diagnosis of histiocytic lymphoma; the third case was shown by immunocytochemistry to be a true Ki-1-positive large cell lymphoma. Histologic and immunohistochemical analysis were performed on surgical biopsies from 18 patients. The results were in agreement with those on the fine needle aspiration (FNA) material in 14 cases. Three lymphomas could be phenotyped on aspirated material while marker studies on excised material were inconclusive. One lymph node aspirate contained mostly necrotic cells, which were unsatisfactory for adequate immunocytochemistry. However, sections from a removed tonsil from the same patient could be used for conclusive histology and phenotyping. In conclusion, the high diagnostic accuracy of combined cytomorphologic and immunocytochemical assessment of FNA samples validates the use of the technique in the diagnostic work-up of blastic (high-grade malignant) NHLs. In fact, the diagnostic accuracy seems so high that the technique can safely be used in the final diagnosis of blastic NHLs.     

Anaplastic large cell lymphoma of the mediastinum diagnosed by transbronchial scratch cytology. A case report

BACKGROUND: Anaplastic large cell lymphoma (ALCL) is a subtype of non-Hodgkin's lymphoma characterized by CD30 antigen-positive, large neoplastic cells. We describe a case of ALCL suggested by cytologic examination of the tumor cells obtained from bronchial scratch preparations. CASE: A 26-year-old woman had had a dry cough since November 1996. Chest radiography in May 1997 revealed an abnormal shadow in the mediastinum extending to the pulmonary hilar region. The patient was hospitalized in June 1997. Computed tomography revealed a neoplastic lesion in the anterior mediastinum invading the right lung. Transbronchial scratch cytology revealed large, atypical lymphoid cells expressing CD30 and CD3 on immunocytochemical examination. A transcutaneous mediastinal biopsy was performed and a diagnosis of ALCL made. CONCLUSION: Differentiation from Hodgkin's disease was the most difficult point in this case. Detailed cytologic observation and CD3-positive immunocytology led to the correct diagnosis. The cell transfer technique of Sherman et al was very useful for immunocytologic staining. Thus, transbronchial scratch cytology was an especially valuable and effective procedure in this case.     

Fine needle aspiration of pediatric abdominal masses. Cytologic and electron microscopic diagnosis.

Fine needle aspiration (FNA) was performed under ultrasound guidance on 17 abdominal masses in 16 pediatric patients at Baragwanath Hospital. The aspirated cellular material was assessed by conventional cytomorphology and by electron microscopy (EM). A diagnosis of malignancy was rendered for all 15 tumors that were adequately sampled (88.2%); the remaining 2 masses yielded insufficient material for either light microscopy or EM. Cytologic cell typing (including the use of EM) was successful in 12 of the 15 tumors (80%) as compared with the histologic diagnosis. EM was in agreement with the initial cytologic diagnosis in eight tumors, but corrected the initial impression in four tumors. The tumors with adequate aspirates included nine nephroblastomas and single examples of neuroblastoma, hepatoblastoma, non-Hodgkin's lymphoma, rhabdomyosarcoma, renal carcinoma and malignant rhabdoid tumor. The last three were not accurately typed by cytology plus EM. These preliminary results suggest that FNA cytology with adjunctive EM could become a useful technique in the preoperative assessment of pediatric abdominal tumors.     

Cytologic findings of breast ductal lavage and concurrent fine needle aspiration in pleomorphic lobular carcinoma in situ: a case report

BACKGROUND: Breast ductal lavage (DL) is a noninvasive procedure for sampling ductal epithelial cells. Patients at risk for breast cancer or with prior history can be monitored by DL. This report compares cytomorphology in concurrent DL, fine needle aspiration (FNA) and histology in a case of pleomorphic lobular carcinoma in situ (PLCIS) with signet ring features. CASE: A 57-year-old woman had DL and FNA performed after quadrantectomy for lobular carcinoma in situ with signet ring cell features. DL and FNA were diagnosed as suspicious and positive for malignancy, respectively. Subsequent biopsy showed PLCIS. Cytomorphologic features of DL, FNA and histology were compared. DL showed epithelial cells in small clusters or single-file arrangement and single-lying; in FNA, single cells predominated. DL and FNA showed nuclear atypia and cytoplasmic vacuoles, the latter more prevalent in FNA. Both samples showed cells with signet ring features. The atypical epithelial cells present in DL and FNA were identical to those seen in the histologic material. CONCLUSION: Cytomorphologic findings in DL, although less striking, are comparable to those seen in FNA. Architecture, nuclear atypia and intracytoplasmic vacuoles are helpful features in DL for establishing a diagnosis of suspicious if not positive for malignancy in LCIS.     

Fine needle aspiration cytology in the diagnosis of non-Hodgkin's lymphomas of the muscle: a report of 2 cases

BACKGROUND: Primary skeletal muscle lymphoma has been reported in very few cases. Although such imaging techniques as computed tomography and magnetic resonance imaging can supply diagnostic indications, the most reliable data are obtained by means of muscle biopsy investigations. Fine needle aspiration cytology (FNAC) has not been considered before for the diagnosis of muscle lymphoma. CASES: In case 1, 60-year-old man presented with 2 masses in the pectoral muscle and neck. FNAC of the neck mass was performed. The diagnosis was non-Hodgkin's diffuse B-cell lymphoma of the muscle; the diagnosis was confirmed by surgical biopsy of the pectoral muscle. In case 2, a 70-year-old man presented with a mass in the quadriceps muscle. The results of FNAC aroused suspicion of lymphoma, and a muscle biopsy confirmed the presence of a non-Hodgkin's B-cell lymphoma. Immunohistochemistry identified it as non-Hodgkin's marginal zone B-cell lymphoma of MALT type. CONCLUSION: FNAC can be a valuable starting point in muscle involvement by lymphoma because of the possibility of obtaining material by means of multiple aspirations without causing patients any discomfort.     

Non-Hodgkin¿s Lymphoma of the synovium discovered in total knee arthroplasty: a case report

ABSTRACT: BACKGROUND: Musculoskeletal involvement occurs in 25% of patients with non-Hodgkin's lymphoma (NHL). Primary lymphoma in the joint is rare. It can present as a bone lesion or as atypical soft tissue proliferation. NHL has an increased incidence in patients with autoimmune rheumatic diseases. CASE PRESENTATION: We present a case in which non-Hodgkin's lymphoma was found coincidentally in the synovium during knee joint replacement surgery in a 69-year old woman with rheumatoid arthritis. Pigmented, vitreous tissue was resected, which turned out to be a diffuse large B-cell lymphoma after histological examination. The coincidental intraoperative finding of intra-articular non-Hodgkin's lymphoma was reported twice before, presenting as synovial proliferation in elbow and shoulder surgery. In a few other cases non-Hodgkin's lymphoma presented most often in the knee, as a bone lesion or, when soft tissue was involved, as arthritis. CONCLUSION: Non-Hodgkin's lymphoma should be considered in patients with autoimmune rheumatic diseases. In case of persistent arthritis, non-respondent to anti-inflammatory drugs, a biopsy might be warranted. Moreover, when arthroscopy or arthrotomy is planned, any atypical tissue should be sent for histological analysis. Early diagnosis of NHL can contribute to improved outcome of its rapidly developing treatment options.