Utilization Of Combined Flow Cytometry And Fine-needle Aspiration Cytology In The Diagnosis And Subclassification Of Lymph Nodal Non-Hodgkin Lymphoma

Background and objectiveLymphomas are a high heterogeneous group of neoplasms, which are among the most complicated in typing,specially non-Hodgkin lymphoma(NHL) . In the current World Health Organization classification, all lymphomas are distinct clinicopathologic entities defined based on their morphology, immunophenotype, clinical features and genetic alterations (in several cases).Thus, immunophenotype plays an important role in the diagnosis of lymphomas. Flow cytometry(FCM) is a new technique to analyze and select individual cells. FCM offers many advantages as compared to immunohistochemistry(IHC),such as fast procedure, high sensitivity and multiparameter evaluation. Fine-needle aspiration cytology(FNC) is a simple,fast and accurate method in diagnosing neoplasm, but the role of FNC in diagnosing lymphoma is still controversial. FNC was considered as primary diagnosis of lymphoma before, but combining immunophenotype and genetic alterations could enhance the precision of diagnosis. The applications of FCM combined with FNC in the diagnosis of lymphomas can be complementary. According to many reports abroad, flow cytometry combined with fine-needle aspiration cytology is a high sensitive and specific technique for the diagnosis of NHL, but the domestic research and applications are less than that of the abroad. We studied the FCM immunophenotyping in FNC of lymph nodes. Information from FCM was combined with cytomorphologic evaluation and then compared with tissue biopsy results. The aim was to study the usefulness and limitations of this technique in the diagnosis and subclassification of NHL.Materials and methodsSmears from cases of palpable lymph node by FNC were collected between May,2006 and March,2007.If the smear suggested NHL or benign reactive hyperplasia (BRH), then a second aspiration was performed to collect a second sample from the same anatomic site. The monoclonal antibodies included CD19,κ/λ, CD5, CD10, CD23, CD3,CD2, CD7. Flow cytometry was performed to analyze the immunophenotyping of lymphoid cells. FCM/FNC diagnoses were compared with the histopathological diagnosis.Results1. In 39 cases, a combined flow cytometric-cytopathologic diagnosis was made. Of the total 39 cases, 21 were diagnosed as NHL, 13 as BRH, 5 as suggestive of NHL. Of the 21 cases of NHL, 14 were B-NHL and 7 were T-NHL. Out of 14 B-NHL on FCM/FNC diagnosis, Light chain restriction was seen in 13 B-NHL (92.86%) and subclassification was performed in 11(78.57%)B-NHL. Of the 11 B-NHL, there were 3 B-small lymphocytic lymphoma(B-SLL), 3 follicular lymphoma(FL) and 5 diffuse large B cell lymphoma(DLBCL). 3 B-NHL couldn't be subclassified. Out of 7 T-NHL on FCM/FNC diagnosis, one or more pan-T antigens were lost in 6 cases, but it didn't allow further subclassification.2. Tissue biopsy was performed in all the 39 cases and out of which there were 26 NHL, 12 BRH and 1 histiocytic necrotizing lymphadenitis. Of the 26 NHL,16 were B-NHL and 10 were T-NHL. Out of 14 B-NHL with histopathology, there were 3 B-SLL, 1 mantle cell lymphoma(MCL), 4 FL and 8 DLBCL. Out of 10 T-NHL with histopathology, there were 6 peripheral T-cell lymphoma(P-TCL), 2 T lymphoblastic lymphoma(T-LBL) and 2 anaplastic large cell lymphoma(ALCL).3. Of the 39 cases with histologic diagnosis, 33 cases(84.62%) were correctlydiagnosed by FCM/FNC diagnosis. For the diagnosis of NHL and BRH ,thecoincident rate between FCM/FNC diagnoses and histopathology were 80.77%(21/26) and 100% (12/12) .Among the NHLs, the coincident rate of B-NHL andT-NHL were 87.50% (14/16) and 70.00% (7/10) .Conclusions1. Light chain restriction is the main immunologic features of B-NHL. FCM combined with FNC is a high sensitive and specific technique for the diagnosis of B-NHL and allows further subclassification in most of the cases.2 .The diagnosis of T-NHL is more challenging. One of the most useful criteria to diagnose a T-cell neoplasm is aberrant lack one or more of the pan-T antigens.3. Polyclonal immunophenotyping and a morphologically reactive pattern can diagnose BRH confirmly, but significantly enlarged or clinically suspicious lymph nodes may have to be biopsied.4. FCM/FNC diagnosis isn't of great value in diagnosing the cases of lymphoid neoplasm contained a mixed population of benign and neoplastic lymphoid cells, such as T-cell-rich large B-cell lymphoma and occasionally, partial tissue involvement by B-NHL.