The WHO classification of lymphomas: cost-effective immunohistochemistry using a deductive reasoning "decision tree" approach: part II: the decision tree approach: diffuse patterns of proliferation in lymph nodes

Ultrasensitive RNA in situ hybridization for detection of restricted clonal expression of low-abundance immunoglobulin light chain mRNA in B-cell lymphoproliferative disorders

OBJECTIVES

To assess the feasibility of using a novel ultrasensitive bright-field in situ hybridization approach (BRISH) to evaluate κ and λ immunoglobulin messenger RNA (mRNA) expression in situ in B-cell non-Hodgkin lymphoma (NHL).

METHODS

A series of 110 semiconsecutive clinical cases evaluated for lymphoma with historic flow cytometric (FCM) results were assessed with BRISH.

RESULTS

BRISH light chain restriction (LCR) results were concordant with FCM in 108 (99%) of 109 evaluable cases. Additional small B-cell lymphoma cohorts were successfully evaluated.

CONCLUSIONS

BRISH analysis of κ and λ immunoglobulin mRNA expression is a sensitive tool for establishing LCR in B-cell NHL when FCM results are not available.

Thomas Hodgkin: the "man" and "his disease": humani nihil a se alienum putabit (nothing human was foreign to him)

Thomas Hodgkin (1798-1865) was one of the leading physicians and scientists of the nineteenth century. A renowned diagnostician, he carried out pioneering work in public health, but devoted the greater part of his career to the study of pathology. His contributions transcend many fields, medical and non-medical, but his most important legacy to medical science was the recognition of the disease that bears his name. The diagnosis of Hodgkin's disease was difficult pending recognition of the "peculiar giant cells" that came to characterize the diagnosis. With identification of the Reed-Sternberg cell, it might have been expected that debate concerning the nature of Hodgkin's disease would be stilled. History proved to the contrary. A fierce controversy ignited with respect to the cellular origin of the Reed-Sternberg cell and the relationship, if any, of Hodgkin's disease to other malignant processes arising in the "absorbent glands and spleen." For a century, arguments ebbed and flowed, reflective of individual opinions and changing concepts, yielding ultimately to new methods for examining and identifying cells.

Selective immunophenotyping for diagnosis of B-cell neoplasms: immunohistochemistry and flow cytometry strategies and results

Determining the immunophenotype of hematologic malignancies is now an indispensable part of diagnostic classification, and can help to guide therapy, or to predict clinical outcome. Diagnostic workup should be guided by morphologic findings and evaluate clinically important markers, but ideally should avoid the use of overly broad panels of immunostains that can reveal incidental findings of uncertain significance and give rise to increased costs. Here, we outline our approach to diagnosis of B-cell neoplasms, combining histologic and clinical data with tailored panels of immunophenotyping reagents, in the context of the 2008 World Health Organization classification. We present data from cases seen at our institution from 2004 through 2008 using this approach, to provide a practical reference for findings seen in daily diagnostic practice.

Diagnostic Workup of Small B Cell Lymphomas: A Laboratory Perspective

Small B cell lymphoma is a morphological designation to a group of B cell lymphomas which are composed of a clonal population of small lymphoid cells. The subtypes of this category have diagnostically distinct characteristics and different clinical behaviors and treatment. Correct diagnosis and classification of these subsets depend on the integration of morphologic, immunophenotypic, and molecular genetic features. In this paper, differential diagnosis of this category of tumors and a practical approach based on biomarker evaluation are discussed.

A pathologist-in-the-loop IHC antibody test selection using the entropy-based probabilistic method

Background:

Immunohistochemistry (IHC) is an important tool to identify and quantify expression of certain proteins (antigens) to gain insights into the molecular processes in a diseased tissue. However, it is a challenge for pathologists to remember the discriminative characteristics of the growing number of such antigens across multiple diseases. The complexity of their expression patterns, fueled by continuous discoveries in molecular pathology, gives rise to a combinatorial explosion that places an unprecedented burden on a practicing pathologist and therefore increases cost and variability of IHC studies.

Materials and Methods:

To tackle these issues, we have developed antibody test optimized selection method, a novel informatics tool to help pathologists in improving the IHC antibody selection process. The method uses extensions of Shannon's information entropies and Bayesian probabilities to dynamically build an efficient diagnostic tree.

Results:

A comparative analysis of our method with the expert and World Health Organization classification guidelines showed that the proposed method brings threefold reduction in number of antibody tests required to reach a diagnostic conclusion.

Conclusion:

The developed method can significantly streamline the antibody test selection process, decrease associated costs and reduce inter- and intrapathologist variability in IHC decision-making.