A systematic approach to the immunohistologic classification of lymphoproliferative disorders

Intracranial pseudolymphoma

Intracranial pseudolymphoma is a rare tumor of the central nervous system. A 35-year-old woman presented with a frontal subcutaneous tumor. Magnetic resonance imaging revealed a left frontal meningeal tumor involving subcutaneous tissue without bone involvement. The mass was completely removed and the histological aspect of all tumor sections was that of a lymphoid hyperplasia with polyclonal proliferation. These findings were characteristic of pseudolymphoma defined as a hyperplasia of follicular and diffuse lymphoid type with assessment of its polyclonality by immunophenotyping on frozen sections, completed by molecular biology techniques.

Fine-needle aspiration cytology of lymphoproliferative lesions involving the major salivary glands

Fine-needle aspiration biopsy (FNA) is an accurate and cost-effective procedure for evaluating salivary gland lesions. Lymphoproliferative lesions may manifest as salivary gland enlargement. We report our experience with 43 cases of reactive and neoplastic lymphoproliferative lesions of the salivary glands evaluated by FNA, including 23 cases of reactive lymphoid hyperplasia and 20 neoplastic lymphoproliferative processes. The latter included 2 multiple myelomas and 18 non-Hodgkin lymphomas (small lymphocytic lymphoma/chronic lymphocytic leukemia, 1; small cleaved cell lymphoma, 1; lympho-plasmacytoid lymphoma, 1; mucosa-associated lymphoid tissue lymphoma, 2; mixed cell lymphoma, 4; lymphoblastic lymphoma, 1; and large cell lymphoma, 8). There were no false-negative diagnoses. Aspiration smears from 3 patients with reactive lymphoid hyperplasia and 4 patients with malignant lymphoma initially were interpreted as atypical lymphoid proliferations or as suggestive of malignant lymphoma. Thus, FNA had a sensitivity of 100% and a specificity of 87%. The majority of patients were treated medically without surgical intervention. Among the patients who underwent surgical resection of the salivary gland, 7 had an equivocal cytologic diagnosis and 2 had a benign cytologic diagnosis, but their parotid swelling failed to regress despite medical treatment. In most instances, FNA provides useful information for subsequent disease management and obviates surgical intervention.

Oligo-/monoclonal gammopathy and hypergammaglobulinemia in ataxia-telangiectasia. A study of 90 patients

We investigated the presence of hypergammaglobulinemia and oligo-/monoclonal gammopathy in 90 patients (from 80 families) with ataxia-telangiectasia ranging in age from 2 to 29 years. Of the 90 patients, 38.8% displayed hypergammaglobulinemia. An isolated increase in IgM was the most common finding (23.3%) followed by a simultaneous increase in IgM and IgG (8.8%), an isolated increase in IgA (3.3%), an elevated level of IgG (2.2%) and a concomitant increase in IgM and IgA (1.1%), respectively. Seven of the patients (8.1%) had oligo-/monoclonal gammopathy. The gammopathies included all major immunoglobulin isotypes. Chemotherapeutic intervention in 2 cases precipitated the emergence of new clones within a matter of weeks. Further investigation of oligo-/monoclonal gammopathies in these patients may lead to a clearer understanding of the clinical course and provide further insight into the underlying mechanisms of B-cell abnormalities in ataxia-telangiectasia.

Analysis of data on leukocyte surface markers for recognition of leukemia/lymphoma phenotype pattern

OBJECTIVE

This study was designed to test the algorithm for the recognition of leukemia/lymphoma pattern, based on cell immunophenotype assessed using specific monoclonal antibodies and measured using flow cytometry.

DESIGN AND METHOD

Analysis was performed by comparing phenotyping data with reference data, followed by scoring of such comparisons. Output of the recognition was designed as a report list of possible diagnoses (defined as objects in the informatic system). Reference data were compiled from the respective literature.

RESULTS

From 57 blood and bone marrow samples tested in this study, accurate recognition of the real diagnosis (object) appeared on the first four places of the report list in 54 (94.7%) samples.

CONCLUSION

The list of the objects recognized by the use of algorithm appeared to be helpful in making a differential diagnosis, occasionally pointing to the states that the physician had not in mind at the start of the analysis.

Immunohistologic studies of bone marrow biopsies on frozen sections: an analysis of 42 cases

An immunohistologic study of bone marrow biopsy frozen sections from 42 cases involved by a variety of reactive and neoplastic disorders is presented. Thirteen cases also were studied using other methods, including cytochemistry, surface marker analysis of cell suspensions, and/or DNA hybridization. Thirty-four of 42 cases (81%) were adequately phenotyped on frozen tissue using a panel of antibodies for hematolymphoid-associated antigens. The immunostains from the remaining eight cases were unsatisfactory, primarily as a result of heavy background staining. Eighteen cases were lymphoproliferative disorders of B-cell phenotype and 12 of these showed surface monotypic immunoglobulin expression by the frozen section technique. Six cases showed B- or pre-B-cell antigens but no surface immunoglobulins. Of the remaining 16 patients, two cases showed myeloid markers and three showed T-cell phenotype. Nine cases showed a mixture of polyclonal B- and T-cell populations. Keratin was demonstrated in a single case of metastatic carcinoma included in the study. These results indicate that the majority of hematopoietic processes can be successfully phenotyped on bone core frozen sections and demonstrate the usefulness of immunohistologic study of the frozen bone marrow biopsy specimens, especially when the specimens for other modalities are not available or are inadequate. The keys to achieving the best results from the frozen bone marrow immunohistochemistry were the gentle handling of the specimens and the preparation of high-quality, cryostat-cut frozen sections.

A review of the fine-needle aspiration cytology findings in human immunodeficiency virus infection

Patients infected with the human immunodeficiency virus (HIV) are subject to infections and neoplasms, which frequently result in palpable or radiologically identified masses. Fine-needle aspiration (FNA) offers a rapid, simple, and cost effective approach for diagnosis of these masses. During a 2-yr period, 396 aspirates were performed on 362 HIV-infected patients within the LAC-USC Medical Center. Adequate material was obtained from 84% of the FNA, allowing the etiology of the mass to be determined in 90% of the cases by means of a combination of cytologic, microbiologic, and immunocytochemical procedures. Significant pathologic processes identified in these patients by means of FNA included reactive lymphoid proliferations (35%), abnormal lymphoid proliferations (12%), infections (12.5%), cystic (5.5%) and inflammatory processes (5%), nonlymphoid malignancies (4%), and salivary gland pathology (1%). We conclude that FNA is an appropriate initial diagnostic procedure in HIV positive patients presenting with mass lesions.

Cytomorphologic, immunocytochemical, and nucleic acid flow cytometric study of 50 lymph nodes by fine-needle aspiration. Comparison with results obtained by subsequent excisional biopsy

Fifty patients with clinically suspected or previous diagnosis of lymphoma underwent fine-needle aspiration (FNA) and subsequent excisional biopsy of their lymph nodes. Results of cytologic diagnosis made from the direct smears in conjunction with immunocytochemical study of cytospin preparations and nucleic acid flow cytometric study (FCM) were compared with the results obtained from histologic sections, cryostat-immunohistochemical study, and nucleic acid FCM performed on resected lymph nodes. This study demonstrates (1) results of immunocytochemical and DNA-FCM analysis of FNA-derived material are comparable in the majority of cases to those obtained from surgical specimens, (2) immunostaining of cytospin preparations for immunoglobulin (Ig) gives less background staining and in certain cases is easier to interpret than when performed on frozen sections, and (3) monotypia in FNA in conjunction with cytomorphologic study is 100% specific for lymphoma, and polytypic staining for Ig does not exclude HD, T-cell lymphoma, or B-cell malignancy focally involving a lymph node.

Genotype and phenotype: a practical approach to the immunogenetic analysis of lymphoproliferative disorders

Determination of cell lineage and clonality in lymphoproliferative disorders (LPD) is greatly enhanced by molecular genetic analysis in conjunction with morphologic and immunologic techniques. We now report on a technique in which we used cryostat-cut, fresh-frozen sections (CCFFS) prepared from tissues in a manner that allows DNA hybridization studies to be coordinated readily with routine morphologic and immunohistologic studies. Thirty-seven cases representing a broad spectrum of reactive and malignant LPD were examined with this method. Samples of DNA were extracted from frozen sections, subjected to Southern blot hybridization, and probed for rearrangements of the immunoglobulin (Ig) heavy-chain and the kappa and lambda light-chain genes, as well as for the T-cell receptor beta-chain gene. We also evaluated the effects of (1) diagnostic category of LPD, (2) volume of the tissue sample, and (3) fibrosis, necrosis, and ice crystal artifacts in the sample on the recovery of DNA. Ice artifact and sample size had the greatest negative impacts on the quantity and condition of DNA recovered. Of 19 samples involved by B-cell LPD, the results of immunogenetic studies were consistent with the immunophenotypes in all but one case. Of the T-cell lymphomas from which sufficient DNA was available (three out of five of the T-cell cases), all showed rearrangements of the T-cell beta-chain gene. In order to reduce sample processing time, we evaluated alternate blot hybridization methods, rapid alkaline transfers, and direct hybridization of synthetic oligonucleotides in dried agarose gels, and found that they decreased the time required for hybridization studies. In summary, the use of CCFFS as the source of DNA allows study of gene rearrangements and, at the same time, preserves frozen-tissue blocks in tumor banks for further immunologic studies. The development of time-effective methods will make the routine use of molecular-genetic analysis more practical in the diagnostic hematopathology laboratory.

Pulmonary lymphomatoid granulomatosis in seven dogs (1976-1987)

Seven dogs with pulmonary lymphomatoid granulomatosis were reviewed. The disease occurred in six large-breed and one small-breed dogs. The dogs were five to 14 years old (mean, 8.4; median, 7), and four of seven dogs were males. Three dogs had been previously treated with adulticide therapy for canine dirofilariasis. Clinical histories included a progressive respiratory disease characterized by varying degrees of cough, dyspnea, exercise intolerance, and weight loss. Thoracic radiographic features included hilar lymphadenopathy, pulmonary masses of varying sizes, and mixed pulmonary patterns of lobar consolidation with ill-defined interstitial and alveolar pulmonary infiltrates. Cardiovascular changes compatible with chronic dirofilariasis were present in three dogs. The clinical course was usually progressive and fatal. The survival time ranged from six days to four years (mean, 12.5 mos; median, 3 mos). Gross and histologic features included mass lesions with areas of necrosis that replaced normal pulmonary architecture. Cytologically, these lesions were characterized by infiltration with pleomorphic, angioinvasive mononuclear cells that often resulted in vascular obliteration. The infiltrating cells resembled large lymphoid cells that possessed large hyperchromatic nuclei and small amounts of cytoplasm. Systemic lymphoid neoplasia with peripheral lymphadenopathy was diagnosed in two dogs. In both cases, lymph-node cytology was similar to the cellular infiltrates found in the lungs and consistent with a diagnosis of lymphomatoid granulomatosis. These features are compared with previously reported cases of canine lymphomatoid granulomatosis and those features identified in a similar disease described in man.

A clinicopathologic study of malignant lymphomas of the nose, paranasal sinuses, and hard palate, including cases of lethal midline granuloma

Malignant lymphomas of the nose, paranasal sinuses, and hard palate show marked clinicopathologic, immunologic, and prognostic diversity. The clinical features and pathologic spectrum of these lesions were studied in 20 cases (11 female and 9 male cases) with a mean age of 51 years at initial presentation. Malignant lymphomas of the large cell type were most frequently encountered (11/20). The next largest category was malignant lymphoma, diffuse, mixed small and large cell type (six of 20). Two thirds, 13 of 20 cases, had morphologic features suggestive of peripheral T-cell lymphomas. Necrosis, an angiocentric growth pattern, and epitheliotropism were found in nine, eight, and three cases, respectively. Of ten cases immunophenotyped on fresh-frozen or fixed, paraffin-embedded tissue sections, eight had a T-cell phenotype and two had a B-cell phenotype. Of 17 patients with sufficient follow-up data, ten are alive (median follow-up 33 months) and seven are dead (median survival 12 months). Patients with clinical Stages IE and IIE did not have a superior 5-year survival to those with more advanced disease. Histologic type also did not correlate with survival but this may be due to the aggressive histologic grade of the majority of cases and the retrospective nature of this study. The authors conclude that, despite the overall high-grade histologic type, the pathologic spectrum of malignant lymphomas involving this anatomic region is broad. Furthermore, some cases do not fit well into the National Cancer Institute (NCI) Working Formulation but more closely resemble the histologic features of peripheral T-cell lymphomas described in Japan.

Imprint cytology of non-Hodgkin's lymphomas based on a study of 212 immunologically characterized cases: correlation of touch imprints with tissue sections

The classification of non-Hodgkin's lymphomas (NHLs) has been traditionally based on analysis of histologic sections and has been supplemented more recently by immunologic marker studies. It was the purpose of the present study to illustrate, side-by-side, sections and Romanowsky-stained imprints from the same surgical specimen from practically all categories of immunophenotyped NHLs, including rare and atypical variants that were difficult to classify from the histologic sections alone. Our results indicate that imprint cytology may reveal nuclear and cytoplasmic details not discernible in even the best tissue sections and that it may be selectively helpful in contributing to the classification of NHLs. Our results also show that the relative value of imprint cytology in the classification of malignant lymphomas varies greatly among categories. Specifically, we have found that imprints assist in three ways: the recognition of plasmacytoid features in small cell lymphocytic lymphomas, the recognition of plasmacytoid immunoblastic lymphoma, and the differentiation between NHLs which may be difficult to distinguish histologically. These include (1) small lymphocytic lymphoma versus lymphocytic lymphoma of intermediate differentiation, (2) true histiocytic malignancies versus large cell malignant lymphomas with abundant cytoplasm and/or phagocytosis, (3) anaplastic myeloma versus plasmacytoid immunoblastic lymphoma, (4) large noncleaved versus plasmacytoid immunoblastic lymphoma, (5) lymphoblastic lymphoma versus diffuse small cleaved cell lymphoma, and (6) lymphoblastic lymphoma versus small noncleaved cell lymphoma. Lymph node imprints are easy to prepare and readily interpretable by those experienced in the study of abnormal blood and bone marrow films. Their value as an ancillary methodology aimed at optimal accuracy in the classification of NHLs should be recognized.

Immunoglobulin and T cell receptor gene rearrangements and in situ immunophenotyping in lymphoproliferative disorders

We investigated for rearrangements of the immunoglobulin (Ig) heavy and light chain genes and of the T cell receptor gamma (TCR gamma) and beta (TCR beta) genes 45 biopsy samples from a variety of lymphoproliferative disorders. They were diagnosed histopathologically and immunophenotypically as non-Hodgkin's lymphomas (NHLs) of the B cell type (19 cases), NHLs of the T cell type (3 cases), NHLs of "undetermined" cell type (3 cases), atypical lymphoid proliferation (1 case) and AIDS-related lymphadenopathies with florid polyclonal follicular hyperplasia (19 cases). A monoclonal proliferation of B cells was shown by DNA analysis in all 19 B cell NHLs. In two immunohistologically determined T cell NHLs (both diagnosed as mycosis fungoides) the cells had rearrangements of TCR beta gene, whereas in the third case (lymphoblastic NHL) the cells had rearrangements of Ig heavy chain and TCR gamma and TCR beta genes. None of the B cell NHLs exhibited TCR gamma and TCR beta gene rearrangement bands. All the "undetermined" cell NHLs demonstrated rearrangements of Ig heavy chain gene associated with the germ line TCR gamma and TCR beta genes; in two cases light chain gene rearrangements were also found. The atypical lymphoid proliferation, in which the differential diagnosis was between a reactive or malignant process, and two out of 19 cases of florid polyclonal follicular hyperplasia showed a clonal B cell population by DNA analysis. This study indicates that there was a strong correlation between the rearrangements of specific genes and the immunophenotype of the NHL; moreover, DNA analysis of tissue biopsy specimens from phenotypically "undetermined" cell NHLs and from equivocal lymphoid proliferation using Ig and TCR gene probes yielded an answer in the cases analyzed. The significance of clonal B cell expansions found in two AIDS-related lymphadenopathies should be interpreted with caution.

T-cell-rich lymphoproliferative disorders. Morphologic and immunologic differential diagnoses

To differentiate peripheral T-cell lymphomas (PTCL), the authors evaluated the results of T11 monoclonal antibody studies on consecutive cell suspensions prepared from 509 lymph nodes from various lymphoproliferative disorders (LPD). They used T11 (CD2) positivity to identify those LPD in which the content of T cells was high. There were 266 (52%) cell suspensions which contained more than 50% T11-positive cells. More than 75% of the following non-Hodgkin's lymphomas had over 50% T11-positive cells: diffuse mixed cell (DM), diffuse atypical poorly differentiated lymphocytic and lymphoblastic lymphomas; mycosis fungoides; and true histiocytic lymphoma. Eleven cell suspensions had more than 90% T11-positive cells; four were involved by B-cell lymphomas. The cell suspensions prepared from nine of 14 diffuse large cell lymphomas of the T-cell type had more than 50% T11-positive cells. Of these, three of five cases of the polymorphous subtype had fewer than 50% T11 cells, but six of seven lymph nodes of the clear-cell type had more than 50% T11-positive cells. Each of seven DM samples of the T-cell type contained over 50% T11 cells; none had a polymorphous appearance. In the 112 cases of reactive LPD studied, more than 75% of cases of necrotizing lymphadenitis, dermatopathic lymphadenitis, angioimmunoblastic lymphadenopathy, and those with lymph nodes with no specific reactive pattern had more than 50% T11-positive cells. The authors' findings indicate that T11 positivity is a reliable T-cell marker in reactive and neoplastic LPD except for those cases of PTCL with a polymorphous appearance; these tend to lose T11-expression. A multi-parameter diagnostic approach is required in the following LPD: (1) PTCL which are T11-negative; (2) PTCL of small lymphocytic type having an unremarkable T-cell phenotype; (3) SIg-negative B-cell lymphomas which are rich in nonneoplastic T cells; (4) non-Hodgkin's lymphomas with minimal disease which are rich in reactive T cells; and (5) polymorphous large cell proliferations.

Variability in interpretation of immunohistologic findings in lymphoproliferative disorders by hematopathologists. A comprehensive statistical analysis of interobserver performance

Eight hematopathologists independently reviewed 56 consecutive cases of benign and malignant lymphoproliferative disorders (LPD) to determine: (1) the degree of interobserver agreement on the interpretation of immunologic findings on fresh-frozen sections alone and on that of the immunologic findings in conjunction with corresponding hematoxylin and eosin (H & E)-stained histologic sections; (2) whether prior knowledge of morphologic characteristics influences the interpretation of immunohistologic sections; (3) whether immunologic phenotype could be predicted reliably based solely on study of histologic sections; and (4) the significance of immunologic data as an aid in the interpretation of histologic sections. The study was carried out in three independent review sessions consisting of (1) review of immunohistologic sections only, (2) review of the same immunohistologic sections together with histologic sections, and (3) review of the histologic sections alone. A consensus diagnosis was defined as agreement of five or more pathologists on the final diagnosis and identification of the immunophenotype. When the authors compared the total number of major disagreements in the first review session with those in the second, the accuracy of the determination of immunophenotype in the second session was clearly superior (P less than 0.05). Similarly, the total number of major disagreements in the second review session was significantly lower than that in the third review session (P less than 0.001). When histologic diagnoses in the second session were compared with those in the third session, it became apparent that the immunologic data helped the pathologist to correct major misinterpretations in 14 cases (25%). This study is the first to demonstrate quantitatively that (1) knowledge of morphologic features influences and greatly enhances the accuracy of the interpretation of immunologic findings, (2) the immunophenotype of LPD cannot be predicted based on morphologic findings alone, and (3) immunologic findings improve the accuracy of interpretation of histologic findings in situations in which a diagnosis cannot be made from morphologic features only.

Immunoarchitecture of the "pseudofollicles" of well-differentiated (small) lymphocytic lymphoma: a comparison with true follicles

Some human malignant lymphomas of the B-cell type have morphologic and immunologic similarities to follicles seen in nonneoplastic reactive lymph nodes. In contrast, a peculiar, vaguely nodular pattern of growth called "pseudonodules" or "pseudofollicular proliferation centers," which is morphologically distinguishable from "true" follicles, is seen in malignant lymphoma, well-differentiated (small) lymphocytic type (WDL). To characterize the cellular components of "pseudofollicles," we undertook a detailed, comparative immunohistologic study of the architectural relationship and distribution of T cells, B cells, and follicular dendritic reticulum cells (DRCs) in reactive follicles, neoplastic follicles, and pseudofollicles. We report several observations on the presence of DRCs and T-cell subset topography in pseudofollicles. Immunohistologic staining for the C3d complement receptor on DRCs revealed that DRC networks associated with "true" follicles were present in all cases of reactive follicular hyperplasia (RFH) and malignant lymphoma, nodular, poorly differentiated lymphocytic type (PDL) studied. Surprisingly, DRC networks were also identified in 8 of 23 cases of WDL. Although the size distribution of DRC network diameters was nearly identical in RFH and PDL, the sizes were markedly diminished in WDL. Immunohistologic staining for Leu 3+ and Leu 2+ T-cell subsets confirmed cellular arrangements in RFH and PDL reported by others. In only 2 of 23 cases of WDL could T cells localized to "pseudofollicles" in frozen tissue sections be identified in a nonrandom arrangement.