Laboratory Workup of Lymphoma in Adults.

OBJECTIVES: The diagnostic workup of lymphoma continues to evolve rapidly as experience and discovery lead to the addition of new clinicopathologic entities and techniques to differentiate them. The optimal clinically effective, efficient, and cost-effective approach to diagnosis that is safe for patients can be elusive, in both community-based and academic practice. Studies suggest that there is variation in practice in both settings. THE AIM OF THIS REVIEW IS TO: develop an evidence-based guideline for the preanalytic phase of testing, focusing on specimen requirements for the diagnostic evaluation of lymphoma. METHODS: The American Society for Clinical Pathology, the College of American Pathologists, and the American Society of Hematology convened a panel of experts in the laboratory workup of lymphoma to develop evidence-based recommendations. The panel conducted a systematic review of the literature to address key questions. Using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach, recommendations were derived based on the available evidence, the strength of that evidence, and key judgments as defined in the GRADE Evidence to Decision framework. RESULTS: Thirteen guideline statements were established to optimize specimen selection, ancillary diagnostic testing, and appropriate follow-up for safe and accurate diagnosis of indolent and aggressive lymphoma. CONCLUSIONS: Primary diagnosis and classification of lymphoma can be achieved with a variety of specimens. Application of the recommendations can guide decisions about specimen suitability, diagnostic capabilities, and correct utilization of ancillary testing. Disease prevalence in patient populations, availability of ancillary testing, and diagnostic goals should be incorporated into algorithms tailored to each practice environment.

Laboratory Workup of Lymphoma in Adults: Guideline From the American Society for Clinical Pathology and the College of American Pathologists.

CONTEXT.­: The diagnostic workup of lymphoma continues to evolve rapidly as experience and discovery led to the addition of new clinicopathologic entities and techniques to differentiate them. The optimal clinically effective, efficient, and cost-effective approach to diagnosis that is safe for patients can be elusive, in both community-based and academic practice. Studies suggest that there is variation in practice in both settings. OBJECTIVE.­: To develop an evidence-based guideline for the preanalytic phase of testing, focusing on specimen requirements for the diagnostic evaluation of lymphoma. DESIGN.­: The American Society for Clinical Pathology, the College of American Pathologists, and the American Society of Hematology convened a panel of experts in the laboratory workup of lymphoma to develop evidence-based recommendations. The panel conducted a systematic review of literature to address key questions. Using the Grading of Recommendations Assessment, Development, and Evaluation approach, recommendations were derived based on the available evidence, strength of that evidence, and key judgements as defined in the Grading of Recommendations Assessment, Development, and Evaluation Evidence to Decision framework. RESULTS.­: Thirteen guideline statements were established to optimize specimen selection, ancillary diagnostic testing, and appropriate follow-up for safe and accurate diagnosis of indolent and aggressive lymphoma. CONCLUSIONS.­: Primary diagnosis and classification of lymphoma can be achieved with a variety of specimens. Application of the recommendations can guide decisions on specimen suitability, diagnostic capabilities, and correct use of ancillary testing. Disease prevalence in patient populations, availability of ancillary testing, and diagnostic goals should be incorporated into algorithms tailored to each practice environment.

Scoring of MYC protein expression in diffuse large B-cell lymphomas: concordance rate among hematopathologists.

Recent studies have shown that immunohistochemical evaluation of MYC protein expression in diffuse large B-cell lymphoma is a useful prognostic tool with high concordance rate among pathologists. Concordance in these studies was assessed among few pathologists from one institution by scoring tissue microarrays. In daily practice, MYC evaluation is performed on entire tumor sections by a diverse group of pathologists. In our study, nine hematopathologists from two institutions scored whole-tissue sections of two sets of cases. The training set included 13 cases of diffuse large B-cell lymphoma and 4 cases of Burkitt lymphoma. The validation set included 18 cases of diffuse large B-cell lymphoma and 1 case of Burkitt lymphoma. MYC positivity was defined as ≥40% of tumor cells demonstrating nuclear staining similar to prior studies. The mean score for each case was used to determine MYC status with discrepant cases defined as having any score causing a different MYC status designation. Discrepant cases from the training set were characterized by staining heterogeneity, extensive necrosis or crush artifact and had mean scores within 15 percentage points of 40%. Cases from the validation set that demonstrated any of these features were scored twice on two different days. Overall concordance was moderate (Kappa score: 0.68, P-value<0.001) with no significant change between the two sets (Kappa scores: 0.69 vs 0.67). Thirty-nine percent of cases were discrepant. The findings indicate that a significant number of diffuse large B-cell lymphomas are inherently difficult to score due to staining heterogeneity. The effect of heterogeneity can be under-represented when concordance is measured among few pathologists scoring tissue microarrays. Careful scoring strategy in our study failed to improve concordance. In the absence of specific instructions on how to deal with heterogeneity, caution is advised when evaluating MYC expression in diffuse large B-cell lymphoma.

Bone marrow examination for unexplained cytopenias reveals nonspecific findings in patients with collagen vascular disease.

CONTEXT: Collagen vascular diseases are frequently included in the differential diagnosis for unexplained cytopenias and often prompt a bone marrow biopsy in this patient population to exclude malignancy. Few large-scale studies have characterized the bone marrow morphology in patients with collagen vascular disease, and most are limited to systemic lupus erythematosus or rheumatoid arthritis. OBJECTIVE: To identify morphologic and immunohistochemical abnormalities specific to each of a wide range of collagen vascular disease cases. DESIGN: We examined 102 cases of collagen vascular disease and 38 controls and evaluated the complete blood count, peripheral blood morphology, bone marrow morphology, as well as immunohistochemical staining, for numerous cell lineages. RESULTS: Bone marrow findings, including abnormalities such as lymphoid aggregates, lipogranulomas, or abnormal localization of immature precursors, were not significantly different as compared to the control group. CONCLUSIONS: Bone marrow examination in patients with collagen vascular disease with cytopenias seldom provides new information. Caution should be exercised in interpreting morphologic findings suggestive of myelodysplasia since these are of a reactive nature in up to 27% of patients with collagen vascular disease. In a cost-effective diagnostic strategy, successful utilization may favor postponing a bone marrow biopsy while a more standardized autoimmune diagnostic panel is being performed.

Acetic acid-zinc-formalin: a safe alternative to B-5 fixative.

B5 fixation achieves superior morphologic detail. However, environmental concerns have led to labor-intensive and costly requirements for disposal of mercury-containing fixatives. We performed a blinded prospective study to find a safe, mercury-free alternative to B5. Morphology was evaluated with 6 fixatives, including B5, in a blinded fashion. Acetic acid-zinc-formalin (AZF) was selected for further evaluation of immunohistochemistry, in situ hybridization, and molecular analysis. AZF fixation resulted in overall staining and morphologic detail comparable to B5 and achieved equivalent or superior antigen preservation for immunohistochemical studies. Strong signal intensity was achieved with in situ hybridization, and DNA amplification could be successfully performed. AZF allows greater flexibility in fixation times, decreases decalcification time, and eliminates labor-intensive steps required for B5 processing.

A new human natural killer leukemia cell line, IMC-1. A complex chromosomal rearrangement defined by spectral karyotyping: functional and cytogenetic characterization.

A new human IL-2 dependent leukemic cell line with a natural killer (NK) cell phenotype, IMC-1, was established from an adult patient with aggressive NK cell leukemia. The IMC-1 cell line expresses the CD56, CD2, CD11a, CD38 and HLA-DR cell surface antigens, whereas the CD16 and CD8 antigens expressed on the primary leukemic blasts from which the cell line was derived were lost after 7 and 28 weeks of culture, respectively. The IMC-1 cell line displays functional NK cytotoxicity and lyses target cells in a non-MHC restricted, antibody-independent manner with equal or superior efficiency to freshly isolated NK cells. Cytogenetic analysis at presentation and after 55 weeks in culture revealed complex structural and numerical abnormalities, defined by classic G-banding and by spectral karyotyping (SKY). Three apparently intact copies of chromosome 8 occurred in the diagnostic bone marrow specimen; the cell line also contains three copies of chromosome 8 but each was structurally altered. The development and detailed characterization of this new NK leukemic cell line will facilitate biologic and functional studies of NK cells and chromosomal aberrations potentially important in leukemic transformation.