The role of flow cytometric immunophenotyping in improving the diagnostic accuracy in referred fine-needle aspiration specimens

Flow cytometric (FCM) immunophenotyping has an important role in the diagnostic work up of fine-needle aspiration (FNA) specimens obtained from lymphoid lesions. The objective of the present study was to evaluate the feasibility of this method with respect to referred FNA specimens. One hundred and two FNA specimens referred to our laboratory for FCM analysis during the last 3 years were studied. Specimens were sent, accompanied by cytological smears, from 11 distant hospitals by ordinary mail. The evaluation of potential B-cell monoclonality, the main diagnostic issue to be resolved using FCM, was possible in 86 of these 102 cases. The remaining 16 samples could not be analyzed or adequately interpreted because of sparse or necrotic material. A monoclonal B-cell population was found in 17/86 satisfactory cases, of which 16 were histologically confirmed. Eight cases contained cells positive for the epithelial marker Ber-EP4 and were diagnosed accordingly as carcinomas. FCM analysis of specimens obtained with a clinical question of Hodgkin lymphoma or T-cell lymphomas did not yield definitive data. The time lapse between sampling and analysis (12-84 hr) did not affect the results. This probably was due to the fact that all aspirates were taken in Roswell Park Memorial Institute (RPMI) cell medium, supplemented with 50% fetal calf serum. In conclusion, this retrospective study establishes that it is possible, in the majority of cases, to refer FNA material for FCM immunophenotyping by mail, and that results regarding B-cell clonality in the case of small-cell lymphomas are reliable also after a transportation period of 3-4 days. Carcinoma may be similarly diagnosed and a diagnosis of lymphoma may be excluded in reactive proliferations. Cases with only a few atypical cells or specimens from patients suspected of having Hodgkin lymphoma or T-cell lymphomas are not suitable for analysis by FCM.     

Immunophenotypic and genotypic characterization of primary non-Hodgkin's lymphoma of the gastrointestinal tract

Antigen receptor gene rearrangement studies have been applied to gastrointestinal (GI) lymphoid proliferations in only a limited number of cases, and their use and contribution to the diagnosis and characterization of GI lymphomas is unknown. We retrospectively studied 17 cases of primary GI lymphoma using fresh/frozen tissue with a combination of immunophenotypic and genotypic techniques. The vast majority of the neoplasms were B-cell lymphomas (88%) with rare T-cell tumors. The most common B-cell immunophenotype was IgM-kappa (40%), while five of the B-cell lymphomas (33%) lacked surface light chain immunoglobulin. Immunophenotypic evidence of histiocytic differentiation was not identified. Clonality was confirmed in 59% (10/17) of the neoplasms by immunophenotyping and 88% (15/17) by antigen receptor gene rearrangement studies. All of the 15 B-cell lymphomas (100%) demonstrated clonally rearranged immunoglobulin gene rearrangement. The two lymphomas with T-cell immunophenotypes did not demonstrate T-cell receptor beta-chain gene rearrangement. Antigen receptor gene rearrangement data can be useful and may even be necessary in certain cases for the proper classification and/or diagnosis of GI lymphoid proliferations.     

Immunoglobulin-gene rearrangements as unique clonal markers in human lymphoid neoplasms

Immunoglobulin genes in their germ-line form are separated DNA subsegments that must be joined by means of recombinations during B-cell development. Individual immunoglobulin-gene rearrangements are specific for a given B cell and its progeny. We show that the detection of such gene rearrangements by Southern hybridization provides a sensitive marker for both clonality and B-cell lineage within lymphoid tissues lacking expression of definitive surface phenotypes. We have used these genetic markers in three ways: to establish a diagnosis of lymphoma in a neoplastic disorder of uncertain cell type, to show that some lymphomas that were previously classified as being of T-cell type in fact contain monoclonal B cells, and to detect clonal B-cell populations within lymphomatous tissues of uncertain immunotype and within an atypical lymphofollicular hyperplasia having no other clonal surface markers. These sensitive and unique indicators of clonality located directly at the DNA level are capable of providing insights into the cellular origin, early detection, and natural history of neoplasia.     

Distribution of lymphoid neoplasms in china: analysis of 4,638 cases according to the world health organization classification

To estimate the distribution of lymphoid neoplasms in China, we conducted a comprehensive analysis, based on subtype, age, sex, and lesion, of primary and resected biopsy specimens of 4,638 lymphoid neoplasms diagnosed from 2004 to 2008 at 5 large hospitals. Of the 4,638 patients, mature B-cell neoplasms accounted for 64.3% of all lymphoid neoplasms, mature T/NK-cell neoplasms for 23.3%, and Hodgkin lymphoma for 8.6%. The most common subtype was diffuse large B-cell lymphoma (36.2%), followed by extranodal NK/T-cell lymphoma, nasal type (11.0%), classic Hodgkin lymphoma (8.4%), extranodal marginal zone B-cell lymphoma (7.7%), plasmacytic neoplasm (5.0%), and peripheral T-cell lymphoma, not otherwise specified (3.9%). For most lymphoid neoplasm subtypes, male subjects showed higher rates than female subjects. In summary, our study showed that the epidemiologic features of lymphoid neoplasms in China are distinct from those in Western countries and similar in many ways to those in other countries of the Far East.     

Immunoreactivity of B-cell markers (CD79a, L26) in rare cases of extranodal cytotoxic peripheral T- (NK/T-) cell lymphomas.

The monoclonal antibodies L26 (CD20) and CD79a are very useful reagents for the immunohistochemical assessment of B-cell lineage in lymphoproliferative disorders. Although very few CD20-positive peripheral T-cell lymphomas (PTL) have been reported, comprehensive analyses of CD79a reactivity in extranodal PTL and NK/T-cell lymphomas have not been performed previously. This study investigated CD79a (clone JCB117) and CD20 reactivity in 94 extranodal non-B-cell lymphomas (enteropathy-type intestinal T-cell lymphoma [n = 52], nasal NK/T-cell lymphoma [n = 11], and primary cutaneous PTL [n = 31]) and in 17 cases of nodal PTL, unspecified. In four cases (enteropathy-type intestinal T-cell lymphoma [n = 3] and nasal NK/T-cell lymphoma [n = 1]), the majority of tumor cells stained for CD79a (all CD20 negative) and one cutaneous PTL, unspecified, was CD20 positive (CD79a negative). Extensive immunophenotyping and polymerase chain reaction-based molecular analyses revealed that all five B-cell marker-positive extranodal lymphomas had a cytotoxic phenotype and did indeed represent monoclonal peripheral T-cell proliferations. To minimize the risk of misinterpretation of lymphoma cell lineage, especially in cases of extranodal, lymphoproliferative disease, we suggest the use of both CD79a and CD20 in combination with a panel of antibodies reactive to T cells, such as betaF1 and CD5, and to T cells and NK cells, such as CD3, CD2, CD56, and TIA-1.     

Comparison of lymphoid neoplasm classification. A blinded study between a community and an academic setting

The revised European-American classification of lymphoid neoplasms has been reported as reproducible among expert pathologists and feasible in a community setting. We evaluated the reproducibility of lymphoid neoplasm diagnoses between a community and an academic center. We subtyped 188 lymphoid neoplasms using revised European-American classification criteria. Clinical findings, histologic or cytologic preparations, paraffin-section immunostains, and flow cytometry data were reviewed as appropriate. Diagnoses were compared only after completion of the study. Lymphoma subtype was concordant for 167 (88.8%) of 188 cases. Discordant cases included 15 B-cell, 2 T-cell, and 4 Hodgkin lymphomas. For B-cell neoplasms, discordance was most often due to classifying diffuse large cell lymphoma as another aggressive subtype of lymphoma (n = 6), marginal zone lymphoma as another subtype (n = 4), or follicle center lymphoma grade II as grade III (n = 3). For Hodgkin disease, discordance was most often due to classifying nodular sclerosis as mixed cellularity type (n = 3). Comparison of community and academic center diagnoses demonstrated high concordance for most revised European-American classification subtypes. Some sources of discordance have been addressed in the new World Health Organization classification of neoplastic diseases of the hematopoietic and lymphoid tissues.     

T-cell receptor beta chain gene rearrangements: genetic markers of T-cell lineage and clonality

We have performed a series of investigations involving T-cell receptor beta chain (T beta) gene rearrangements in benign and malignant nonhematopoietic, B-cell, and T-cell proliferations. These studies provide the conceptual basis and the operational approach for the use of T beta gene rearrangements as markers of T-cell lineage, clonality, and differentiation, analogous to immunoglobulin gene rearrangements in B cells. Southern blot hybridization analysis for T beta gene rearrangements can now be utilized to identify and distinguish between non-T cells, polyclonal T cells, and monoclonal T cells. Determination of T beta gene rearrangements will play an important role in the further investigation and classification of T-cell neoplasia. However, the identification of a genetic marker of clonality for T cells has significant diagnostic and prognostic value as well. For example, determination of the T beta gene rearrangement unique to a particular malignant T-cell clone provides a specific genetic marker for that clonal T-cell proliferation. This genetic marker of the T-cell clone may provide a useful tool for monitoring the patient's therapeutic response and clinical course for early signs of relapse. Nonetheless, our studies demonstrate that the lineage specificity of immunoglobulin and T beta gene rearrangements is not absolute. It appears that only a multiparametric approach combining extensive monoclonal antibody immunophenotypic analysis, in vitro testing for functional help and suppression, and Southern blot hybridization analysis for immunoglobulin and T beta gene rearrangements allows the conclusive and unequivocal demonstration of the B- or T-cell derivation of all lymphoid neoplasms. Lymphoid malignancies that cannot be assigned to the B- or T-cell lineage following this extensive multiparametric analysis are exceedingly uncommon.     

PCR analysis of IgH-gene rearrangements in small lymphoid infiltrates microdissected from sections of paraffin-embedded bone marrow biopsy specimens

The differentiation of benign lymphoid infiltrates from nodular infiltrates of B-cell lymphoma is difficult in bone marrow (BM) biopsy specimens taken from patients with non-Hodgkin's lymphoma (NHL). We investigated whether the determination of clonality by polymerase chain reaction (PCR) analysis of the immunoglobulin heavy chain (IgH) genes could be of help for the distinction of benign and malignant lymphoid infiltrates. BM biopsy specimens of 28 patients were studied, comparing PCR of entire bone marrow sections with microdissected nodular lymphoid infiltrates. Patients were divided into 4 groups according to morphologic criteria: group 1 (n = 12), positive for B-NHL infiltration; group 2 (n = 5), suspicious for infiltration by known B-NHL; group 3 (n = 5), morphologically benign infiltrates in patients with B-NHL; group 4 (n = 6), benign lymphoid infiltrates in patients without history of B-NHL. PCR products were analyzed using polyacrylamide gels and a fragment length analysis system (Genescan). PCR of whole sections showed clonal amplification products in all cases of group 1 and 1 case of group 2. PCR analysis from microdissected nodular infiltrates showed the presence of a clonal B-cell population in 5 additional cases of groups 2 and 4. In 3 of these cases, clonal rearrangements of corresponding size were obtained from the primary lymphoma biopsy specimens. None of the cases of group 3 showed evidence of a clonal population with either technique. The results indicate that microdissection of small nodular lymphoid infiltrates from paraffin-BM sections increases the sensitivity of IgH gene rearrangement analysis. To avoid detection of biologically irrelevant clonal populations, comparison of PCR products obtained from the BM and the primary lymphoma biopsy is advisable.     

T-cell malignancy following B-cell lymphoma in remission

A T-cell malignancy developed in a 64-year-old man with recurrent B-cell lymphoma after one and a half years of remission. Immunophenotypic and DNA analyses confirmed clonality and cell lineage of both lymphoid malignancies. Sequential development of B- and T-cell malignancies in this patient may be an example of biclonal lymphoma or treatment-related secondary lymphoma. However, another possibility would be the existence of a transformed lymphoid stem cell that underwent intraclonal conversion from B- to T-cell lines.     

Monoclonal analysis of immunoglobulin heavy chain and T-cell receptor gamma chain gene rearrangements in paraffin-embedded tissues from non-Hodgkin lymphoma patients

Gene rearrangement is an important diagnostic marker of malignant lymphoma, and rearrangements of the immunoglobulin heavy chain (IgH) and T-cell receptor gamma chain (TCRgamma) genes are useful markers for Band T-cell lymphoma, respectively. A polymerase chain reaction (PCR) can be used to analyze clonality in formalin-fixed paraffin-embedded specimens. We performed 73 monoclonal analyses of such specimens of lymphoma tissues and examined the ability to diagnose malignant lymphoma by this method. Monoclonality of lymphoma cells was found in 71.9% and 78.9% of specimens with IgH and TCRgamma gene rearrangements, respectively. Therefore, in diagnosing cases of non-Hodgkin lymphoma in which neoplasms and reactive lymphoid tissues are difficult to identify by morphological and immunohistochemical findings, PCR-based monoclonal analysis may allow confirmation of a pathological diagnosis of malignant lymphoma.     

The routine diagnostic utility of immunoglobulin and T-cell receptor gene rearrangements in lymphoproliferative disorders

Immunophenotypic studies have a well-documented role in the assignment of lineage in the lymphoproliferative disorders. With the exception of mature B-cell disorders, it is difficult to demonstrate clonality by immunophenotypic studies. The advent of specific DNA probes for immunoglobulin and T-cell receptor genes has greatly facilitated the detection of clonality and, to a lesser degree, lineage, in these cases. The authors have evaluated the diagnostic utility of these probes and compared them with standard immunophenotyping in 65 patients with a variety of lymphoproliferative disorders. Their results show a significant correlation (P less than 0.01) between lineage assignment as determined by phenotyping and gene rearrangement studies, with the latter far superior in determining clonality. Furthermore, analysis of gene rearrangements facilitated the documentation of lineage and/or clonality in six cases in which standard techniques had failed. Although the scientific basis of the study of gene rearrangements has been well established, the authors wish to emphasize the role that these techniques have in evaluating problem cases in the routine diagnostic laboratory.     

Role of polymerase chain reaction and immunocytochemistry in the cytological assessment of lymphoid proliferations

BACKGROUND: Fine-needle aspiration cytology (FNAC) is used as a screening test to evaluate lymphadenopathy. The combined use of genetic analysis and flow cytometry for immunophenotyping has increased the accuracy of diagnosis and correct categorisation of lymphomas on cytological preparations. AIM: To show the utility of immunocytochemistry and polymerase chain reaction (PCR) in the evaluation of cytological preparations of lymph nodes. METHODS: Fine needle aspirates were obtained from 33 patients (initial presentation, n = 27; recurrence, n = 6). Routine examination was undertaken using immunocytochemistry and DNA PCR to detect clonality and specific translocations. The cytodiagnosis and subclassification of lymphoma was correlated with histological diagnosis in the available follow-up biopsies. RESULTS: 14 patients had a cytological diagnosis of non-Hodgkin's lymphoma (NHL), 4 had suspected NHL, 2 had atypical lymphoid proliferation and 13 had reactive hyperplasia. A World Health Organization (WHO) subtype was suggested in 8 patients. Incorporating the results of immunoglobulin heavy chain (IgH) and T-cell receptor (TCR) gene rearrangements enabled diagnosis of lymphoma in 17 patients, including 5 of the 6 patients suspected to have NHL or an atypical lymphoid proliferation. Identification of the translocations t (14;18) and t (2;5) helped WHO categorisation in 3 of the patients. The cytological findings were confirmed in 12 out of the 13 patients for whom histological follow-up was available. Seven of the 18 lymphoma patients were managed without a subsequent biopsy. We made one false-positive diagnosis of B-cell NHL on cytology. CONCLUSION: The use of immunocytochemistry and PCR is valuable in the definitive diagnosis and subtyping of malignant lymphomas on cytological preparations. The use of these techniques may avoid lymph node biopsies in some cases and allow definitive treatment based on aspirate findings alone.     

Bone marrow trephines containing lymphoid aggregates from patients with rheumatoid and other autoimmune disorders frequently show clonal B-cell infiltrates

In bone marrow trephines, morphological and immunohistochemical criteria may not be sufficient to discriminate reactive from malignant lymphoid infiltrates. The aim of this study was to determine whether the detection of clonal immunoglobulin heavy chain (IGH) gene rearrangements is a reliable and specific marker for malignant B-cell clones in bone marrow biopsies. Bone marrow trephines with infiltration by different types of low-grade B-cell non-Hodgkin lymphoma (n = 32), reactive lymphoid hyperplasia (n = 18), and reactive lymphoid aggregates (n = 15), including 5 patients with rheumatoid or other autoimmune disorders, were analyzed by morphology, immunohistochemistry, IGH gene rearrangement (polymerase chain reaction), and DNA sequence analysis in selected cases. In 22 (68.8%) of 32 patients with B-cell non-Hodgkin lymphoma, a clonal IGH gene rearrangement was detected. Of the reactive cases, 1 of 18 patients with lymphoid hyperplasia demonstrated clonality, and 9 (60%) of 15 patients with reactive lymphoid aggregates gave a clonal result (GeneScan analysis). DNA sequence analysis was performed in 7 of the latter patients confirming clonality in 6. Four of the patients with B-cell clonality had an autoimmune disorder. None of these patients developed a malignant lymphoma during follow-up. Thus, the molecular detection of a clonal rearrangement of the IGH gene may support the diagnosis of a malignant lymphoma infiltrating the bone marrow. However, morphologically and immunohistochemically benign lymphoid aggregates might also harbor B-cell clones especially in patients with autoimmune disorders. Therefore, the detection of clonality has to be interpreted with utmost care and does not qualify for the unequivocal diagnosis of a malignant B-cell lymphoma.     

Molecular genetics and the diagnosis of lymphoma

Gene rearrangement analysis has emerged as a precise laboratory aid in the diagnosis and classification of malignant lymphoma and leukemia. Both clonality and lineage can be identified in lymphoid neoplasms by the demonstration of rearrangements of antigen receptor genes of the immunoglobulin supergene family--immunoglobulin and T-cell receptor genes. Rearrangement analysis is not only useful in differential diagnosis and classification, but also serves as a sensitive unique clonal marker to detect early occult recurrence in patients after therapy. In a similar manner, chromosomal translocations associated with specific disease types can be detected with DNA probes in Southern blot analysis without the use of conventional cytogenetics. Using this approach, one may diagnose specific chromosomal translocations associated with histologic types of lymphoma and leukemia. When appropriately applied, DNA rearrangement analysis complements conventional histology, immunophenotyping, and cytogenetics.     

Flow cytometric immunophenotyping of cerebrospinal fluid specimens

Flow cytometric immunophenotyping (FCI) is recommended in the evaluation of cerebrospinal fluid (CSF) specimens for hematologic neoplasms. This study reviewed FCI of CSF specimens collected for primary diagnosis (n = 77) and follow-up for known malignancy (n = 153). FCI was positive in 11 (4.8%) of 230 specimens: acute myeloid leukemia, 6; precursor B-acute lymphoblastic leukemia, 2; B-cell lymphoma, 2; and T-cell lymphoma, 1. Positive results were obtained in low-cellularity specimens, including 2 with fewer than 100 events in the population of interest. FCI was indeterminate in 19 (8.3%) of 230 specimens, including 3 with only sparse events, 8 with possible artifact (apparent lack of staining, nonspecific or background staining, and aspirated air), and 8 with phenotypic findings considered insufficient for diagnosis. Indeterminate specimens were often limited by low cellularity and lacked normal cell populations to evaluate for appropriate staining. FCI may be of value in low-cellularity CSF specimens, although the results should be interpreted with caution.     

Diagnosis of malignant lymphoma in effusions from patients with AIDS by gene rearrangement

Patients infected with human immunodeficiency virus are prone to a wide variety of lymphoproliferative disorders. In these patients the clinical presentation of malignant lymphoma often overlaps with that of benign lymphoid proliferations. Both may include lymphadenopathy, splenomegaly, blood and bone marrow dyscrasias, and lymphocyte-rich effusions. Because benign and malignant lymphocyte-rich effusions, as well as effusions from other malignancies, may contain large cells that resemble immunoblasts or Burkitt's cells, cytomorphologic characteristics alone are unreliable for definitive diagnosis of malignant lymphoma. Usual immunotyping panels using antibodies to B- and T-cell markers frequently fail to demonstrate cell lineage in lymphoma cells of patients with acquired immune deficiency syndrome (AIDS). The authors used gene rearrangement to confirm the diagnosis of malignant lymphoma in effusions from three patients with AIDS when routine cell marker studies failed to demonstrate cell lineage or clonality. Use of biotinylated probes eliminated the need for handling radioactive material and enabled performance of studies in a routine immunohistochemistry laboratory.     

A practical approach to immunophenotyping of lymphomas. Comparison of immunohistologic and immunocytologic techniques

Comparison of immunohistologic (IH) and immunocytologic (IC) techniques was conducted on 86 specimens. Forty-seven B-cell, five T-cell, and two null-cell lymphomas were identified by IH as well as 16 cases of lymphoid hyperplasia. The results of IC were generally identical to those of IH except for two T-cell and two B-cell lymphomas. The diagnosis of T-cell lymphoma was a major problem for IC because of the presence of normal T-cell count and/or normal helper/suppressor ratio in these cases. Twenty-one percent of the B-cell lymphomas failed to express surface immunoglobulin but did express B1 and HLA-DR antigens. Such a discrepancy was not demonstrated in cases of lymphoid hyperplasia, thus serving as a useful criterion in the diagnosis of B-cell lymphoma. While combined IH and IC should be used for immunophenotyping in large medical centers, IH is recommended for community hospitals. The identification of kappa, lambda, B1 and T11 (Leu 5) antigens in frozen sections with the immunoperoxidase technique should be sufficient to phenotype most lymphoproliferative diseases. The criteria for immunophenotyping of lymphomas are discussed.     

The "CD43 only" phenotype. An aberrant, nonspecific immunophenotype requiring comprehensive analysis for lineage resolution.

Paraffin section immunohistology of leukocytic proliferations is a routine method of immunophenotyping in many clinical laboratories. Furthermore, a relatively standard antibody screening panel that includes L26 (CD20), Leu22 (CD43), and UCHL1 (CD45RO) appears to be widely used. Although paraffin section immunophenotyping in general, and this panel in particular, have been shown to be very reliable in defining B-cell lineage, characterization of T-cell lineage is less definitive. This is related primarily to the relatively poor specificity of the commercially available T-cell-associated reagents. CD43 (Leu22) in particular has a broad immunoreactivity profile that has not been stressed adequately in some reports. Seventeen cases with a "CD43 only" phenotype were identified during the last several years while using the relatively standard screening panel mentioned above. These cases were quite heterogeneous with respect to cellular differentiation and most were not T-cell proliferations. Specifically, eight cases were extramedullary leukemic infiltrates (five myeloid, two monocytic, one mixed lineage), four cases were T-cell lymphomas, three cases were B-cell lymphomas and two cases were plasmacytomas. Although CD43 has demonstrable utility in a leukocyte screening panel, this report stresses the aberrancy and lack of specificity of the "CD43 only" phenotype. Caution is recommended in assigning a specific lineage to such cellular proliferations without additional immunologic or genotypic analysis. Recommendations for comprehensive diagnostic evaluation of these proliferations are provided.     

B淋巴细胞增生性疑难病例中IgH基因克隆性重排的分析

目的 探讨IgH基因克隆性重排对B淋巴细胞增生性疑难病变的辅助诊断价值.方法 检测77例B淋巴细胞增生性疑难病例中IgH基因的克隆性重排情况,均采用BIOMED-2系统IgH克隆性试剂盒中FR1、FR2、FR3三组家族引物进行PCR及聚丙烯酰胺凝胶电泳,硝酸银染色后观察,并对照最终病理诊断进行分析.结果 77例病变的最终病理诊断:B淋巴细胞反应性增生12例,不能排除B淋巴细胞不典型增生或淋巴瘤20例,B细胞性淋巴瘤45例.三组中FR1、FR2和FR3至少有一个为阳性的比值分别为2/12、11/20(55%)和36/45(80%).B细胞性淋巴瘤中,FR1、FR2和FR3的阳性率分别为60%(27/45)、60%(27/45)、56%(25/45),其类型有边缘区B细胞性淋巴瘤20例(其中黏膜相关淋巴组织型结外边缘区淋巴瘤18例,结内边缘区淋巴瘤2例),弥漫性大B细胞淋巴瘤7例,滤泡性淋巴瘤7例,套细胞性淋巴瘤1例,Burkitt淋巴瘤1例,浆细胞瘤4例,不能分型5例.FR1、FR2和FR3三者检测均为阴性但仍诊断为淋巴瘤9例(20%),其中1例后来出现肝脏B细胞淋巴瘤.对IgH基因重排阳性的B淋巴细胞反应性增生和不典型增生14例的随访结果,4例重新取活检后诊断为B细胞性淋巴瘤,其中3例IgH基因重排检测为阳性.结论 联合检测IgH基因FR1、FR2和FR3克隆性重排对B淋巴细胞增生性疑难病变诊断有重要的辅助价值;对形态改变和免疫表型诊断淋巴瘤依据不足而基因重排阳性者,重取活检或随访有一定价值;对阴性病例有必要补充IgH基因重排及IgK和IgL基因重排的检测以提高检测敏感性.     

Cytology and immunophenotyping of low- and intermediate-grade B-cell non-Hodgkin's lymphomas with a predominant small-cell component: a study of 56 cases

Diagnosis of non-Hodgkin's lymphomas based on cytologic evaluation of fine-needle aspirates and body cavity fluids has gained increasing acceptance. However, the accurate diagnosis and classification of low- and intermediate-grade B-cell lymphomas with a predominant small-cell population still present a diagnostic challenge. In this study, we reviewed the cytology and immunophenotype of 56 cases of low- and intermediate-grade non-Hodgkin's B-cell lymphomas composed of predominantly small cells, with histologic correlation in all cases. These cases consisted of 23 small lymphocytic lymphomas (SLL), 15 follicular center lymphomas (FCL), grade I (small cell predominant), 8 lymphoplasmacytoid lymphomas (LPL), 6 mantle-cell lymphomas (MCL), and 4 marginal zone lymphomas (MZL) including mucosa-associated lymphoid tissue (MALT) lymphoma. Histologic comparison was available in all cases. A cytologic diagnosis of malignant lymphoma was made in 46 (82%) cases. Based on cytomorphology and immunophenotyping of cytologic material, 39 (85%) cases were correctly classified using the Revised European and American Lymphoma classification. In 7 (11%) cases, which included 3 FCLs, 2 MALT lymphomas, and 2 SLLs, the findings were atypical but not diagnostic of lymphoma. There were 3 (5%) false-negative cases. They were 2 SLLs and a FCL. Immunophenotyping done in 4 "atypical" cases was noncontributory. No marker studies were done in the remaining "atypical" case and all false-negative cases. We conclude that cytology, when used in conjunction with immunophenotyping, can accurately diagnose and in most instances subclassify low- and intermediate-grade B-cell non-Hodgkin's lymphoma with a predominant small-cell population.