No abstract

Ten years of cumulative experience represented by 4,902 consecutive diagnostic bonemarrow examinations at a tertiary care and referral center were reviewed to assess the value of specific components. While it has been shown previously that the information obtained from each component is generally complementary, the inclusion of some or all components may vary between institutions. The components studied included aspirate smears, clot sections, biopsy cores, and touch imprints of biopsy and clot sections. Three clinical presentations accounted for the majority of cases: staging for carcinoma or lymphoma, cytopenias, and acute leukemia. We conclude that bilateral aspirates with biopsies are required for diagnosis in staging of neoplasms and that a unilateral aspirate with biopsy is sufficient to assess patients with cytopenia or leukemia. Only rarely were touch imprints of biopsy cores necessary to establish a diagnosis; however, their early availability prior to examining sections of the clot and core did provide immediate information, when positive, in the staging of patients with carcinoma. In a small percentage of staging and leukemia cases the diagnosis rested with the clot section alone. The findings in this study address common assumptions associated with routine diagnostic hematology and oncology procedures, and are important to both clinicians and pathologists concerned with accuracy, quality assurance, turnaround time, and cost containment. Am.

Context.—Reed-Sternberg cells in classic Hodgkin lymphoma are enigmatic and difficult to study because they are so sparse. Tissue microdissection allows for the isolation of single Reed-Sternberg cells. Isolated Reed-Sternberg cells show clonal immunoglobulin gene rearrangement indicating a B-cell origin. Rarely, Reed-Sternberg cells in classic Hodgkin lymphoma express T-cell antigens, suggesting a possible T-cell origin. Objective.—To determine whether there is a difference in genotype between classic Hodgkin lymphoma and classic Hodgkin lymphoma expressing T-cell antigens and to document T-cell clonality. Design.—We studied 4 cases of Hodgkin lymphoma with a characteristic phenotype and immunoreactivity for CD2 and CD3. Single CD30+ Reed-Sternberg cells from each case were isolated by laser capture microdissection for immunoglobulin heavy chain and T-cell receptor-γ genes by polymerase chain reaction studies. Comparative genomic hybridization was performed in all cases. Results.—Two of 4 cases showed clonal rearrangement of the T-cell receptor-γ; none showed immunoglobulin heavy chain rearrangement. Two control cases were negative for T cell receptor-γ but 1 showed immunoglobulin heavy chain rearrangement. Comparative genomic hybridization analysis revealed significant overlap in genomic alteration in Hodgkin lymphoma cases regardless of genotype or phenotype and several regions of imbalance specific to CD3+ Hodgkin lymphoma cases. All patients are alive with no evidence of disease from 10 to 44 months. Conclusions.—Our findings suggest that a T-cell phenotype classic Hodgkin lymphoma can be supported by genotypic studies and that there may be cytogenetic differences between classic Hodgkin lymphoma and Hodgkin lymphoma expressing T-cell antigens.

Context.—Activation-induced cytidine deaminase, necessary for immunoglobulin somatic hypermutation and class switch recombination, is usually expressed within the follicular dendritic network but is also expressed in a population of interfollicular large B cells outside the germinal center. Objective.—To report 7 cases of diffuse large B-cell lymphoma with a distinct paracortical distribution. Expression of activation-induced cytidine deaminase, previously described in interfollicular large B cells, was evaluated. Design.—A panel of immunohistochemical markers, including double staining for activation-induced cytidine deaminase and CD20, was used to illustrate the cases. Molecular studies were performed by polymerase chain reaction in the paraffin-embedded tissue for t(14;18) chromosomal translocation and immunoglobulin heavy chain and T-cell receptor rearrangements. Results.—Patients included 3 males and 4 females ranging in age from 11 to 59 years (mean, 39 years). All specimens were lymph nodes (4 from the groin, 2 from the neck, and 1 from the axilla). Malignant lymphocytes were positive for CD20 and negative for CD5 and CD10. Staining for CD30, CD43, and BCL-2 was variable. The malignant cells showed at least focal staining with activation-induced cytidine deaminase. All cases were found to be monoclonal by immunoglobulin heavy-chain gene rearrangement or showed light-chain restriction. None of the tested cases showed t(14;18). Conclusions.—Diffuse large B-cell lymphoma with a paracortical distribution is unusual and may be a distinct morphologic variant. More study is necessary to determine the stage of B-cell development and the cell of origin of these tumors. However, activation-induced cytidine deaminase expression suggests they may arise from a putative interfollicular large B cell.