Evaluation of deep learning training strategies for the classification of bone marrow cell images

BACKGROUND AND OBJECTIVE

The classification of bone marrow (BM) cells by light microscopy is an important cornerstone of hematological diagnosis, performed thousands of times a day by highly trained specialists in laboratories worldwide. As the manual evaluation of blood or BM smears is very time-consuming and prone to inter-observer variation, new reliable automated systems are needed.

METHODS

We aim to improve the automatic classification performance of hematological cell types. Therefore, we evaluate four state-of-the-art Convolutional Neural Network (CNN) architectures on a dataset of 171,374 microscopic cytological single-cell images obtained from BM smears from 945 patients diagnosed with a variety of hematological diseases. We further evaluate the effect of an in-domain vs. out-of-domain pre-training, and assess whether class activation maps provide human-interpretable explanations for the models' predictions.

RESULTS

The best performing pre-trained model (Regnet_y_32gf) yields a mean precision, recall, and F1 scores of 0.787±0.060, 0.755±0.061, and 0.762±0.050, respectively. This is a 53.5% improvement in precision and 7.3% improvement in recall over previous results with CNNs (ResNeXt-50) that were trained from scratch. The out-of-domain pre-training apparently yields general feature extractors/filters that apply very well to the BM cell classification use case. The class activation maps on cell types with characteristic morphological features were found to be consistent with the explanations of a human domain expert. For example, the Auer rods in the cytoplasm were the predictive cellular feature for correctly classified images of faggot cells.

CONCLUSIONS

Our study provides data that can help hematology laboratories to choose the optimal training strategy for blood cell classification deep learning models to improve computer-assisted blood and bone marrow cell identification. It also highlights the need for more specific training data, i.e. images of difficult-to-classify classes, including cells labeled with disease information.

Inherited bone marrow failure syndromes and germline predisposition to myeloid neoplasia: A practical approach for the pathologist

The diagnostic work up and surveillance of germline disorders of bone marrow failure and predisposition to myeloid malignancy is complex and involves correlation between clinical findings, laboratory and genetic studies, and bone marrow histopathology. The rarity of these disorders and the overlap of clinical and pathologic features between primary and secondary causes of bone marrow failure, acquired aplastic anemia, and myelodysplastic syndrome may result in diagnostic uncertainty. With an emphasis on the pathologist's perspective, we review diagnostically useful features of germline disorders including Fanconi anemia, Shwachman-Diamond syndrome, telomere biology disorders, severe congenital neutropenia, GATA2 deficiency, SAMD9/SAMD9L diseases, Diamond-Blackfan anemia, and acquired aplastic anemia. We discuss the distinction between baseline morphologic and genetic findings of these disorders and features that raise concern for the development of myelodysplastic syndrome.

Real-world routine diagnostic molecular analysis for TP53 mutational status is recommended over p53 immunohistochemistry in B-cell lymphomas

Previous studies in patients with mature B-cell lymphomas (MBCL) have shown that pathogenic TP53 aberrations are associated with inferior chemotherapeutic efficacy and survival outcomes. In solid malignancies, p53 immunohistochemistry is commonly used as a surrogate marker to assess TP53 mutations, but this correlation is not yet well-established in lymphomas. This study evaluated the accuracy of p53 immunohistochemistry as a surrogate marker for TP53 mutational analysis in a large real-world patient cohort of 354 MBCL patients within routine diagnostic practice. For each case, p53 IHC was assigned to one of three categories: wild type (staining 1-50% of tumor cells with variable nuclear staining), abnormal complete absence or abnormal overexpression (strong and diffuse staining > 50% of tumor cells). Pathogenic variants of TP53 were identified with a targeted next generation sequencing (tNGS) panel. Wild type p53 expression was observed in 267 cases (75.4%), complete absence in twenty cases (5.7%) and the overexpression pattern in 67 cases (18.9%). tNGS identified a pathogenic TP53 mutation in 102 patients (29%). The overall accuracy of p53 IHC was 84.5% (95% CI 80.3-88.1), with a robust specificity of 92.1% (95% CI 88.0- 95.1), but a low sensitivity of 65.7% (95% CI 55.7-74.8). These results suggest that the performance of p53 IHC is insufficient as a surrogate marker for TP53 mutations in our real-world routine diagnostic workup of MBCL patients. By using p53 immunohistochemistry alone, there is a significant risk a TP53 mutation will be missed, resulting in misevaluation of a high-risk patient. Therefore, molecular analysis is recommended in all MBCL patients, especially for further development of risk-directed therapies based on TP53 mutation status.

Artificial Intelligence for Clinical Flow Cytometry

In this review, the authors discuss the fundamental principles of machine learning. They explore recent studies and approaches in implementing machine learning into flow cytometry workflows. These applications are promising but not without their shortcomings. Explainability may be the biggest barrier to adoption, as they contain "black boxes" in which a complex network of mathematical processes learns features of data that are not translatable into real language. The authors discuss the current limitations of machine learning models and the possibility that, without a multiinstitutional development process, these applications could have poor generalizability. They also discuss widespread deployment of augmented decision-making.

Cell projection plots: A novel visualization of bone marrow aspirate cytology

Deep models for cell detection have demonstrated utility in bone marrow cytology, showing impressive results in terms of accuracy and computational efficiency. However, these models have yet to be implemented in the clinical diagnostic workflow. Additionally, the metrics used to evaluate cell detection models are not necessarily aligned with clinical goals and targets. In order to address these issues, we introduce novel, automatically generated visual summaries of bone marrow aspirate specimens called cell projection plots (CPPs). Encompassing relevant biological patterns such as neutrophil maturation, CPPs provide a compact summary of bone marrow aspirate cytology. To gauge clinical relevance, CPPs were inspected by 3 hematopathologists, who decided whether corresponding diagnostic synopses matched with generated CPPs. Pathologists were able to match CPPs to the correct synopsis with a matching degree of 85%. Our finding suggests CPPs can represent clinically relevant information from bone marrow aspirate specimens and may be used to efficiently summarize bone marrow cytology to pathologists. CPPs could be a step toward human-centered implementation of artificial intelligence (AI) in hematopathology, and a basis for a diagnostic-support tool for digital pathology workflows.

The new WHO and ICC classification systems for myelodysplastic syndromes and their impact on the clinical laboratory

The International Consensus Classification (ICC) and World Health Organization (WHO) proposed significant changes to the diagnostic criteria of myelodysplastic syndromes (MDS) in 2022. The impact of these criteria on hematopathology practice is uncertain. This study aims to evaluate the impact of the 2022 ICC and WHO 5th edition classifications on the diagnosis of cytopenias and MDS. Cases from 2021 performed for primary diagnosis of cytopenia(s)/MDS and their clinical, laboratory, and pathologic findings were reviewed and classified according to the new classification systems. The rate of major changes to the diagnosis was determined and potential pitfalls in the diagnostic approach, laboratory workflow, and clinical communication challenges were investigated. A total of 49 cases were recruited. Major changes to the diagnostic entities were made in 18/49 (37%) cases according to the WHO 5th edition, and 23/49 (47%) cases classified according to the ICC. The difference was accounted for by five cases of MDS-EB2 (revised WHO 4th edition) classified as MDS/AML (major change) in the ICC in contrast to no significant change (MDS-IB2) in the WHO 5th edition. MDS-SLD cases were not subject to major reclassification according to either system. The new molecularly defined categories of CCUS/CHIP, MDS-SF3B1, and MDS with biallelic TP53 mutations were almost identically represented in both systems in our cohort. A case of MDS-MLD was reclassified as CMML by both classification systems. There are few but important differences between the new MDS classification systems. A preimplementation assessment is helpful to identify diagnostic and potential clinical impacts of their adoption.

Implementation and Evaluation of Virtual Laboratory Tours for Laboratory Diagnosis of Hematologic Disease

Objectives

There is often limited time allocated to teaching laboratory medicine to medical students. Without adequate time and context, it can be difficult for students to learn appropriate uses and limitations of laboratory tests. Introducing students to the laboratories and test methods may help them learn these concepts, but physical laboratory tours are difficult to organize for large groups, especially during the coronavirus disease 2019 pandemic.

Methods

We created virtual laboratory tours consisting of short video clips and voiceover PowerPoint slides to teach students about the laboratory tests used to diagnose hematologic malignancies. We assessed the impact on student performance on laboratory medicine–themed quiz questions and surveyed the students to determine their attitudes about the activity.

Results

In total, 129 first-year medical students participated in the study. The average score on the preactivity quiz was 59.8%, and the average score on the postactivity quiz was 92.2%. Students were more confident in their ability to answer quiz questions after completing the activity. Postactivity survey data indicated that the students enjoyed the activity and felt it was an effective way to learn the material.

Conclusions

Virtual laboratory tours show promise as a method of incorporating more laboratory medicine content into medical school curricula.

Global Cytopathology-Hematopathology Practice Trends

OBJECTIVES

Small-volume biopsy-fine-needle aspiration biopsy (FNAB) with or without core biopsy-is in increasing use in diagnosis and management of lymphoma patients. Our objective was to survey the current practice in small-volume biopsy diagnosis of lymphoma, focusing on the interaction among hematopathologists and cytopathologists and the integration of FNAB, core biopsy, and flow cytometry studies at sign-out.

METHODS

This study used a cross-sectional survey design employing the RedCap database distributed via nine pathology professional society email listservs. The survey consisted of 25 multiple-choice questions and several free text fields. In total, 128 pathologists participated.

RESULTS

Most respondents indicated that FNAB specimens in which lymphoma is a diagnostic consideration (FNAB-L) are seen daily or weekly (68/116; 58.6%). However, most institutions have separate hematopathology and cytopathology services (72/116; 62.1%) with inconsistent communication. When communication occurred, respondents were frequently inclined to reconsider their original diagnoses. Barriers identified included lack of communication, inadequate access to diagnostic studies, no formal subspecialty training, and various opinions regarding FNAB in diagnosing lymphoma.

CONCLUSIONS

This survey showed that FNAB-L specimens are common, with a lack of uniformity in how complementary fine-needle aspiration and core biopsy specimens or flow immunophenotyping results are shared across hematopathology and cytopathology services.

Deep learning for bone marrow cell detection and classification on whole-slide images

Bone marrow (BM) examination is an essential step in both diagnosing and managing numerous hematologic disorders. BM nucleated differential count (NDC) analysis, as part of BM examination, holds the most fundamental and crucial information. However, there are many challenges to perform automated BM NDC analysis on whole-slide images (WSIs), including large dimensions of data to process, complicated cell types with subtle differences. To the authors best knowledge, this is the first study on fully automatic BM NDC using WSIs with 40x objective magnification, which can replace traditional manual counting relying on light microscopy via oil-immersion 100x objective lens with a total 1000x magnification. In this study, we develop an efficient and fully automatic hierarchical deep learning framework for BM NDC WSI analysis in seconds. The proposed hierarchical framework consists of (1) a deep learning model for rapid localization of BM particles and cellular trails generating regions of interest (ROI) for further analysis, (2) a patch-based deep learning model for cell identification of 16 cell types, including megakaryocytes, mitotic cells, and four stages of erythroblasts which have not been demonstrated in previous studies before, and (3) a fast stitching model for integrating patch-based results and producing final outputs. In evaluation, the proposed method is firstly tested on a dataset with a total of 12,426 annotated cells using cross validation, achieving high recall and accuracy of 0.905 ± 0.078 and 0.989 ± 0.006, respectively, and taking only 44 seconds to perform BM NDC analysis for a WSI. To further examine the generalizability of our model, we conduct an evaluation on the second independent dataset with a total of 3005 cells, and the results show that the proposed method also obtains high recall and accuracy of 0.842 and 0.988, respectively. In comparison with the existing small-image-based benchmark methods, the proposed method demonstrates superior performance in recall, accuracy and computational time.

The Interpretation of Sequence Variants in Myeloid Neoplasms

OBJECTIVES

To provide an overview of the challenges encountered during the interpretation of sequence variants detected by next-generation sequencing (NGS) in myeloid neoplasms, as well as the limitations of the technology with the goal of preventing the over- or undercalling of alterations that may have a significant effect on patient management.

METHODS

Review of the peer-reviewed literature on the interpretation, reporting, and technical challenges of NGS assays for myeloid neoplasms.

RESULTS

NGS has been integrated widely and rapidly into the standard evaluating of myeloid neoplasms. Review of the literature reveals that myeloid sequence variants are challenging to detect and interpret. Large insertions and guanine-cytosine-heavy areas prove technically challenging while frameshift and truncating alterations may be classified as variants of uncertain significance by tertiary analysis informatics pipelines due to their absence in the literature and databases.

CONCLUSIONS

The analysis and interpretation of NGS results in myeloid neoplasia are challenging due to the varied number of detectable gene alterations. Familiarity with the genomic landscape of myeloid malignancies and knowledge of the tools available for the interpretation of sequence variants are essential to facilitate translation into clinical and therapy decisions.

Elevating Twitter-Based Journal Club Discussions by Leveraging a Voice-Based Platform: #HemepathJC Meets Clubhouse

PURPOSE OF REVIEW

Social media-based scientific journal clubs provide an opportunity to promote published literature to a broader audience and allow robust multi-disciplinary and inter-professional discussion. Hematopathology Journal Club (#HemepathJC) on Twitter has successfully conducted monthly sessions since November 2019, covering topics related to lymphoma and leukemia.

RECENT FINDINGS

To enhance connectivity, multitasking, and productivity, we present our experience of leveraging the voice-based platform Clubhouse concurrent with Twitter. The Twitter and Clubhouse partnership for #hemepathJC holds the potential to increase dissemination of scientific knowledge and further promote journal club format discussion.

Intussusception in a child with Acute Lymphoblastic Leukemia: a remarkable presentation with literature review - a case report

BACKGROUND

Gastrointestinal complications are not uncommon in patients of Acute Leukemia. Intussusception as a complication in leukemia, although described, is exceedingly rare. Also, it is usually seen after chemotherapy and not as a part of the native disease process. This case report aims to highlight such a rare association which warrants clinical and pathological attention.

CASE PRESENTATION

A 14 year old male presented with an acute abdomen. Initial routine investigations revealed a deranged blood picture. On further examination of bone marrow aspirate, biopsy and detailed immunohistochemical studies a diagnosis of B-Acute Lymphoblastic Leukemia (B-ALL) was made. Concurrent ultrasound of the abdomen to find a cause for severe abdominal pain revealed an Ileo-colic intussusception. The patient was started on steroids; however he succumbed to his illness after two days, before surgery could be attempted.

CONCLUSION

Rare presentations of relatively common diseases are a hurdle for timely and effective medical intervention. Although a rare condition in itself in leukemic patients, the occurrence of Intussusception in this particular patient, especially when no chemotherapy was initiated, is a very rare event. This case report was made to add to the relatively scarce literature available on this particular association. As it is a surgically treatable condition and since delay in diagnosis may lead to poorer prognosis, possibility of co-existence of ALL and intussusception should be borne in mind by all treating physicians and hematopathologists for effective patient care.

Hematopathologic Correlates of CAR T-Cell Therapy

CD19-targeting chimeric antigen rector (CAR) T-cell products are used for the treatment of relapsed/refractory B-acute lymphoblastic leukemia, diffuse large B-cell lymphoma, and mantle cell lymphoma. The success of CD19-CAR-T cells has led to the investigation of CAR T-cell products targeting different antigens in other hematological malignancies and solid tumors. Clinical laboratories play an important role in the manufacture, distribution, and monitoring of CAR T-cell therapy. Hence, it is important for laboratory professionals to be cognizant of clinicopathologic aspects of CAR T-cell therapy.

The Emerging Role of Hematopathologists and Molecular Pathologists in Detection, Monitoring, and Management of Myeloid Neoplasms with Germline Predisposition

PURPOSE OF REVIEW

Awareness, widespread availability, and routine use of sequencing techniques in work-up of myelodysplastic syndromes and acute myeloid leukemia have facilitated increased recognition of these entities arising in a background of germline predisposition disorders (GPD).

RECENT FINDINGS

The latest revisions to the WHO classification of myeloid neoplasms incorporate "myeloid neoplasms with germline predisposition" as a separate entity due to the therapeutic implications of this diagnosis. It has become apparent that some of these entities have unique recognizable morphologic findings that can be challenging to interpret at time. Hence, much needs to be studied, posing a new layer of complexity to hematopathologists and oncologists. A thorough understanding of cytogenetic and molecular findings during disease evolution is essential. Consequently, hematopathologists and molecular pathologists play an increasing role in recognition of bone marrow morphologic features that help in recognition of underlying GPD, monitoring, and prompt identification of progression.

Histopathology of Human Donor Spleen Utilized as a Desensitization Tool Before Intestinal Transplantation

OBJECTIVES

To describe the histopathologic and immunophenotypic features of a temporary splenic allograft exposed to massive donor-specific antibody (DSA) insult.

METHODS

A human cadaveric donor splenic allograft was temporarily transplanted in a highly sensitized patient with the intention of removing DSA before intestinal transplantation from the same donor. Before splenic transplant, the patient had several preformed cytotoxic DSAs that resulted in positive flow cytometric and complement-dependent cytotoxicity crossmatch. The splenic allograft was removed before intestinal transplantation and evaluated by H&E and immunohistochemical stains.

RESULTS

Explanted donor splenic allograft showed several histopathologic changes: expanded red pulp secondary to congestion and marked neutrophilic and macrophage infiltration in the sinusoids, numerous neutrophilic microabscesses, and focal capillaritis. The C4d and IgG immunohistochemical stains were diffusely positive in the endothelial lining of the capillaries and sinusoidal lining, indicating diffuse IgG deposition and complement activation.

CONCLUSIONS

We propose that the noted changes are features of splenic acute antibody-mediated rejection (AMR). Additional cases are required to determine all the features of splenic AMR. To our knowledge, this is the first report of histopathologic changes in donor spleen after exposure to DSA for a short duration.

Discrepancies in digital hematopathology diagnoses for consultation and expert panel analysis

Digital pathology with whole-slide imaging (WSI) has a large potential to make the process of expert consultation and expert panel diagnosis more rapid and more efficient. However, comparison with the current methods is necessary for validation of the technique. In this study, we determined if digital assessment of whole-slide images of hematopathology specimens with a focus on the assessment of lymphoma can be used for consultation and panel diagnostics. Ninety-three histological specimens with a suspicion for lymphoma were assessed both with conventional microscopy and digital microscopy with a wash out period between assessments. A consensus diagnosis was based on full concordance between the pathologists or, in case of discordances, was reached at a joint session at a multi-headed microscope. In 81% of the cases, there was a full concordance between digital and light microscopical assessment for all three pathologists. Discordances between conventional microscopy and digital pathology were present in 3% of assessments. In comparison with the consensus diagnosis, discordant diagnoses were made in 5 cases with digital microscopy and in 3 cases with light microscopy. The reported level of confidence and need for additional investigations were similar between assessment by conventional and by digital microscopy. In conclusion, the performance of assessment by digital pathology is in general comparable with that of conventional light microscopy and pathologists feel confident using digital pathology for this subspecialty.

Pediatric Lymphoid and Histiocytic Lesions in the Head and Neck

Lymphoid and histiocytic lesions of the head and neck in pediatric patients is a fascinating topic as most of these lesions are benign, but that the neoplastic cases are essential to diagnose accurately for appropriate treatment. It is thought that 90% of children will have palpable lymph nodes between the ages of 4 to 8; most, but not all, are non-malignant and some resolve spontaneously without treatment. This paper will look at many of the benign and malignant lesions of both lymphocytic and histiocytic origin that present in the head and neck of children focusing on their diagnostic criteria. There is a very pertinent discussion of nonmalignant lymphoid proliferations, as infections and other reactive conditions dominate the pathology of pediatric lymphohistiocytic head and neck lesions. Discussion of those lymphomas which arise more frequently in the head and neck focuses on those seen in children and young adults such as classic Hodgkin lymphoma and Burkitt lymphoma, as well as new more controversial entities such as pediatric-type follicular lymphoma. Histiocytic lesions, both benign and malignant, are described and may be challenging to diagnose.

Applications of next-generation sequencing in hematologic malignancies

In the last decade, next-generation sequencing (NGS) has rapidly progressed from a research method to a core component of standard-of-care clinical testing. In oncology, tumor sequencing provides a critical tool to detect somatic driver mutations that not only characterize disease but also impact therapeutic decision-making. Here, we review the important role of NGS in the evaluation of hematopoietic neoplasms. We discusstechnical and practical considerations relevant in somatic mutation testing, emphasizing issues unique to blood cancers. Then, we describe how NGS data is being used to facilitate diagnosis, inform prognosis, guide therapy selection, and even monitor disease. This broad overview highlights the transformative impacts NGS data provides throughout the clinical course of patients with hematologic malignancies.

Acute Myeloid Leukemia Case Harboring Unusual FLT3 Variant: Somatic vs Germline?

FLT3 mutations are considered a prognostic and predictive marker. Here we report on a patient with a rare FLT3 germline variant in the context of relapsed acute myeloid leukemia (AML). A female patient aged 57 years presented with AML with mutations in the IDH2, ASXL1, and DNMT3A genes. She underwent allogenic hematopoietic stem cell transplant but relapsed 2 years posttransplant. Targeted next generation sequencing identified a new missense variant in the FLT3 tyrosine kinase domain c.2440G > T (p.A814S). The treating team considered the possibility of patient eligibility for an FLT3 inhibitor. Because both somatic and germline mutations can be identified in tumor tissue with high-throughput sequencing, it becomes important to distinguish the origin of these alterations when possible-especially, in this challenging case, to define the treatment modality. Simultaneous tumor/germline sequencing allows for the identification of rare germline mutations and may help in determining their significance in the pathogenesis of disease.

Social Media for Hematopathologists: Medical Practice Reinvented-#Hemepath

PURPOSE OF REVIEW

Social media engagement by medical professionals with varied background subspecialties has steadily gained popularity in recent years. As a heavily visual discipline, pathology has been able to leverage social media platforms for trainee education, curbside and official consultations, interdisciplinary communication, and interactions among medical professionals and patient education. The pathology community has been at the forefront of using social media as an educational forum, and the hematopathology community has emerged as one of the strongest and most influential presences on these online platforms. In this review, we perform an in-depth analysis of various Twitter metrics to demonstrate key trends in the usage of social media as it pertains to hematopathology using the hashtag #Hemepath and we describe specific details on how hematopathologists have managed to take advantage of Twitter in furthering our mission of advancing medical education and disseminating knowledge using these innovative virtual educational experiences.

RECENT FINDINGS

The hematopathology community has a great degree of enthusiasm among residents, fellows, and faculty in sharing educational material using case-based examples, participating in group-based online activities, introducing new publications by article authors or readership, and disseminating educational "pearls" from medical conferences, using hashtags and digital images that otherwise would not be readily available to many around the globe. This practice is helping reshape the structure of our field and is providing opportunities to optimize the educational experience by enhancing the instant exposure to cutting-edge information and expert opinions, among other valuable features. The hematopathology community has leveraged social media platforms for disseminating educational material and strengthening interdisciplinary interactions and is a "poster child" for a medical subspecialty that has thrived and flourished by more broadly adopting virtual educational platforms. We hope that this review will provide details on how social media platforms can be used by others in the medical field to achieve similar goals.

Automated design for recognition of blood cells diseases from hematopathology using classical features selection and ELM

In the human immune system, the white blood cells (WBC) creates bone and lymphoid masses. These cells defend the human body toward several infections, such as fungi and bacteria. The popular WBC types are Eosinophils, Lymphocytes, Neutrophils, and Monocytes, which are manually diagnosis by the experts. The manual diagnosis process is complicated and time-consuming; therefore, an automated system is required to classify these WBC. In this article, a new method is presented for WBC classification using feature selection and extreme learning machine (ELM). At the very first step, data augmentation is performed to increases the number of images and then implement a new contrast stretching technique name pixel stretch (PS). In the next step, color and gray level size zone matrix (GLSZM) features are calculated from PS images and fused in one vector based on the level of high similarity. However, few redundant features are also included that affect the classification performance. For handling this problem, a maximum relevance probability (MRP) based feature selection technique is implemented. The best-selected features computed from a fitness function are ELM in this work. All maximum relevance features are put to ELM, and this process is continued until the error rate is minimized. In the end, the final selected features are classified through Cubic SVM. For validation of the proposed method, LISC and Dhruv datasets are used, and it achieved the highest accuracy of 96.60%. From the results, it is clearly shown that the proposed method results are improved as compared to other implemented techniques.

Contemporary Classification and Diagnostic Evaluation of Hypereosinophilia

OBJECTIVES

To provide an in-depth review of the classification and diagnostic evaluation of hypereosinophilia (HE), with a focus on eosinophilic neoplasms.

METHODS

A review of published literature was performed, and exemplary HE cases were identified.

RESULTS

Causes of HE are diverse and can be grouped under three categories: primary (neoplastic), secondary (reactive), and idiopathic. Advances in cytogenetics and molecular diagnostics have led to elucidation of the genetic basis for many neoplastic hypereosinophilic disorders. One common molecular feature is formation of a fusion gene, resulting in the expression of an aberrantly activated tyrosine kinase (TK). The World Health Organization endorsed a biologically oriented classification scheme and created a new major disease category, namely, "myeloid/lymphoid neoplasms with eosinophilia and rearrangement of PDGFRA, PDGFRB or FGFR1, or with PCM1-JAK2." Rearrangement of other TK genes and activating somatic mutation(s) in TK genes have also been reported in eosinophilic neoplasms. Diagnostic evaluation of HE involves a combination of clinical, histopathologic, and immunophenotypic analyses, as well as molecular genetic testing, including next-generation sequencing-based mutation panels. The management of primary HE is largely guided by the underlying molecular genetic abnormalities.

CONCLUSIONS

A good knowledge of recent advances in HE is necessary to ensure prompt and accurate diagnosis, as well as to help optimize patient care.

Improving Augmented Human Intelligence to Distinguish Burkitt Lymphoma From Diffuse Large B-Cell Lymphoma Cases

OBJECTIVES

To assess and improve the assistive role of a deep, densely connected convolutional neural network (CNN) to hematopathologists in differentiating histologic images of Burkitt lymphoma (BL) from diffuse large B-cell lymphoma (DLBCL).

METHODS

A total of 10,818 images from BL (n = 34) and DLBCL (n = 36) cases were used to either train or apply different CNNs. Networks differed by number of training images and pixels of images, absence of color, pixel and staining augmentation, and depth of the network, among other parameters.

RESULTS

Cases classified correctly were 17 of 18 (94%), nine with 100% of images correct by the best performing network showing a receiver operating characteristic curve analysis area under the curve 0.92 for both DLBCL and BL. The best performing CNN used all available training images, two random subcrops per image of 448 × 448 pixels, random H&E staining image augmentation, random horizontal flipping of images, random alteration of contrast, reduction on validation error plateau of 15 epochs, block size of six, batch size of 32, and depth of 22. Other networks and decreasing training images had poorer performance.

CONCLUSIONS

CNNs are promising augmented human intelligence tools for differentiating a subset of BL and DLBCL cases.

Practical Application of Fluorescent In Situ Hybridization Techniques in Clinical Diagnostic Laboratories

Fluorescent in situ hybridization (FISH) techniques can be used to identify a range of chromosome abnormalities that are clinically significant in many cancers. Multicolor FISH can be used to identify multiple targets, which can be simultaneously detected in individual cells using digital imaging microscopy. In an era of precision medicine there is a requirement to make a precise diagnosis and to have a molecular classification of the tumor that can guide therapy. Cancer genomics is now regarded as a sub-specialism in pathology and genomic testing needs to be robustly integrated into the routine diagnostic practice.The FISH techniques described in this chapter have been developed over many years in a busy hematopathology diagnostic laboratory. We describe robust in-house methods for both liquid samples (blood and bone marrow mainly) and formalin-fixed paraffin-embedded (FFPE) tissue biopsies that allow for large numbers of slides to be set up in batches. The techniques described are for interphase cells in tissues where metaphase chromosome techniques are generally not applicable. Some of the FISH tests need to be carried out as an "out-of-hours" emergency test to make a critical diagnosis while others provide prognostic information and are used to guide downstream patient management.

Pathology and diagnosis of follicular lymphoma and related entities

Follicular lymphoma (FL) is an indolent, mature B-cell neoplasm classically characterised by the t(14;18)(q32;q21) with constitutive overexpression of the anti-apoptotic protein, BCL2. Most cases present in older adults with slowly progressive lymphadenopathy and follow an indolent clinical course. Typical morphology shows an expansile follicular proliferation with tumour expression of germinal centre markers, and bone marrow involvement at diagnosis is frequent. However, in the recent past, efforts to understand the biological and clinical heterogeneity of FL has effected significant change to the diagnostic approach. While morphological grade, assessed by enumerating large 'centroblasts' in the neoplastic follicles, generally correlates with outcome in systemic nodal FL, variants with high-grade morphology but indolent clinical behaviour have been identified. Given the clinical implications of these FL variants, knowledge of their clinical and histopathological defining features is of paramount importance to the pathologist. Furthermore, as with many areas of diagnostic oncology, precursors to FL have been identified and described with measurable rates of progression to bona fide lymphoma. Accurate diagnosis of these early lesions can often prevent unnecessary therapy and guide appropriate monitoring for disease progression. This review aims to summarise these key pathological and diagnostic features of FL. We further highlight the biological underpinnings of FL that will likely affect the classification, diagnosis, and treatment of patients with lymphoma.

Harmonization of Training, Training Requirements, Board Certification, and Practice of Hematopathology

OBJECTIVES

Hematopathology (HP) is a rapidly changing field with insufficient data to provide guidance to program directors (PDs), the Accreditation Council for Graduate Medical Education, or the American Board of Pathology.

METHODS

Two surveys were performed-one for HP PDs and one, given twice, for HP diplomates doing Maintenance of Certification/Continuing Certification reporting in 2017 to 2018.

RESULTS

Bone marrow (BM), lymph node (LN), and flow cytometry interpretations and peripheral blood/fluid reviews are performed by more than 80% of hematopathologists and are the areas with the greatest amount of training. A smaller proportion of hematopathologists is involved in other HP-related activities. Most PDs believed fellows should perform BM procedures. Interpretation of 400 or more LNs and 500 BMs was PDs' median expectations for fellows. PDs and HP diplomates considered coagulation and benign RBC disorders overemphasized on the certification examination.

CONCLUSIONS

These results highlight how varied the practice of HP is and can provide guidance to HP PDs, those responsible for assessing HP programs, and the American Board of Pathology.

Genetic Testing in the Diagnosis and Biology of Acute Leukemia

OBJECTIVES

The 2017 Workshop of the Society for Hematopathology/European Association for Haematopathology examined the role of molecular genetics in the diagnosis and biology of acute leukemia.

METHODS

Acute leukemias were reviewed in two sessions: "Genetic Testing in Diagnosis of Acute Leukemias" (53 cases) and "Genetics Revealing the Biology of Acute Leukemias" (41 cases).

RESULTS

Cases included acute lymphoblastic leukemia, acute myeloid leukemia, and acute leukemia of ambiguous lineage. Many cases demonstrated genetic alterations of known diagnostic, prognostic, and/or therapeutic significance, while others exhibited alterations that illuminated disease biology. The workshop highlighted the complexity of acute leukemia diagnosis and follow-up, while illustrating advantages and pitfalls of molecular genetic testing.

CONCLUSIONS

Our understanding of the molecular genetics of acute leukemias continues to grow rapidly. Awareness of the potential complexity of genetic architecture and environment is critical and emphasizes the importance of integrating clinical information with morphologic, immunophenotypic, and molecular genetic evaluation.

Quantitative Cytologic Descriptors to Differentiate CLL, Sézary, Granular, and Villous Lymphocytes Through Image Analysis

OBJECTIVES

We aimed to find descriptors to identify chronic lymphocytic leukemia (CLL), Sézary, granular, and villous lymphocytes among normal and abnormal lymphocytes in peripheral blood.

METHODS

Image analysis was applied to 768 images from 15 different types of lymphoid cells and monocytes to determine four discriminant descriptors. For each descriptor, numerical scales were obtained using 627 images from 79 patients. An assessment of the four descriptors was performed using smears from 209 new patients.

RESULTS

Cyan correlation of the nucleus identified clumped chromatin, and standard deviation of the granulometric curve of the cyan of the nucleus was specific for cerebriform chromatin. Skewness of the histogram of the u component of the cytoplasm identified cytoplasmic granulation. Hairiness showed specificity for cytoplasmic villi. In the assessment, 96% of the smears were correctly classified.

CONCLUSIONS

The quantitative descriptors obtained through image analysis may contribute to the morphologic identification of the abnormal lymphoid cells considered in this article.

KLHL6 Is Preferentially Expressed in Germinal Center-Derived B-Cell Lymphomas

OBJECTIVES

KLHL6 is a recently described BTB-Kelch protein with selective expression in lymphoid tissues and is most strongly expressed in germinal center B cells.

METHODS

Using gene expression profiling as well as immunohistochemistry with an anti-KLHL6 monoclonal antibody, we have characterized the expression of this molecule in normal and neoplastic tissues. Protein expression was evaluated in 1,058 hematopoietic neoplasms.

RESULTS

Consistent with its discovery as a germinal center marker, KLHL6 was positive mainly in B-cell neoplasms of germinal center derivation, including 95% of follicular lymphomas (106/112). B-cell lymphomas of non-germinal center derivation were generally negative (0/33 chronic lymphocytic leukemias/small lymphocytic lymphomas, 3/49 marginal zone lymphomas, and 2/66 mantle cell lymphomas).

CONCLUSIONS

In addition to other germinal center markers, including BCL6, CD10, HGAL, and LMO2, KLHL6 immunohistochemistry may prove a useful adjunct in the diagnosis and future classification of B-cell lymphomas.

Evaluation of Opportunities to Improve Hematopathology Diagnosis for Vietnam Pathologists

OBJECTIVES

We evaluate the need for, feasibility of, and impediments to improving hematopathology diagnoses for cancer hospitals in Vietnam.

METHODS

Two hematopathologists from the United States visited three major cancer treatment hospitals in Vietnam to workshop a sampling of difficult hematopathology cases. With Vietnamese pathologists, they toured histopathology, immunohistochemistry, and ancillary laboratory facilities.

RESULTS

Automated tissue processors and slide staining equipment were documented for each of the three hospitals. Between seven and 11 hematopathology cases were reviewed for each hospital. Exact/complete diagnostic concordance was 50% or less for all three laboratories. The major impediments to accurate specific diagnoses were limitations of immunohistochemical stains, limited stains available in house, and, for one of the hospitals, difficulty with interpretation of the immunohistochemistry.

CONCLUSIONS

Vietnamese pathologists would benefit from hematopathology training or opportunities to consult with hematopathologists in the United States. Expert hematopathology consultation services are currently unavailable within Vietnam, as postgraduate training for laboratory physicians consists of residency training in anatomic pathology only. Limitations in the quality of histopathology and immunohistochemistry could impose a barrier to success of efforts to improve hematopathology diagnosis. Implementation of a histopathology and immunohistochemistry quality improvement program might overcome this limitation.

Data-Driven Iterative Refinement of Bone Marrow Testing Protocols Leads to Progressive Improvement in Cytogenetic and Molecular Test Utilization

OBJECTIVES

To determine the effect of iterative refinement of standard ordering protocols on test utilization and results for bone marrow biopsy specimens.

METHODS

Eighteen months of test utilization and result data were used to revise the protocols that determine cytogenetic and molecular test selection on bone marrow specimens and then compared with data obtained following protocol revision.

RESULTS

Revision of protocols resulted in reduction in total tests and associated charges, due to a decrease in tests both concordant and discordant with the protocols. These reductions only occurred in diseases for which revisions were made and were limited to cases in which reflex testing was performed. There was an increase in the fraction of positive tests, which was also limited to reflex testing.

CONCLUSIONS

Data-driven iterative revision of protocols further improves test utilization and performance, while reducing cost. Analysis of testing data can be used to continuously improve test ordering decisions.

Bone Marrow Conventional Karyotyping and Fluorescence In Situ Hybridization: Defining an Effective Utilization Strategy for Evaluation of Myelodysplastic Syndromes

OBJECTIVES

The current standard of practice for evaluation of myelodysplastic syndromes (MDS) includes peripheral blood and bone marrow morphology review and conventional karyotyping. Karyotype provides a global view of the chromosome complement while fluorescence in situ hybridization (FISH) targets specific abnormalities. The aim of this study was to determine if an MDS-FISH panel would add value beyond karyotype in MDS workup.

METHODS

We studied 505 patients who were evaluated for a possible MDS and had concurrent bone marrow examination, karyotyping, and MDS-FISH performed.

RESULTS

In total, 462 cases had adequate karyotyping (≥20 metaphases) and showed excellent concordance (96%, 445/462) between karyotyping and MDS-FISH. Additional FISH abnormalities had no impact on diagnosis and minimal impact on the cytogenetic prognostic scoring in the myeloid neoplasm cases (2%, 4/206). The concordance rate dropped to 82% (32/39) in the group with insufficient karyotyping (<20 metaphases), and additional FISH findings in this subgroup had no impact on the diagnosis but altered the cytogenetic prognostic scoring in 10% (2/20) of myeloid neoplasm cases.

CONCLUSIONS

In the evaluation of a possible MDS, FISH rarely provides additional value when karyotype is adequate. We propose a value-based, cost-effective algorithmic approach for conventional karyotyping and FISH testing in routine MDS workup.

Extreme Hyperferritinemia: Causes and Impact on Diagnostic Reasoning

OBJECTIVES

Hyperferritinemia can be a result of inflammation, infection, chronic iron overload, or other uncommon pathologies including hemophagocytic lymphohistiocytosis (HLH). There is a historical association between extreme hyperferritinemia and HLH, but in reality HLH is associated with a minority of hyperferritinemic states.

METHODS

We identified conditions most associated with hyperferritinemia by identifying 65,536 serum ferritin levels at the University of Minnesota Hospital over a five-year period, with 86 values higher than 10,000 ng/mL. Pediatric patients comprised 22% of this population, and adults, 78%.

RESULTS

The majority of cases in both populations with hyperferritinemia were due to chronic transfusion (35%), followed by liver disease (27%), and hematologic malignancy (16%). Solid malignancies, infection, macrophage activation syndrome, and primary and secondary HLH comprised the remaining (22%).

CONCLUSIONS

Although this supports the relationship between extreme hyperferritinemia and HLH, it maintains that the positive predictive value of hyperferritinemia for HLH is quite low, and one should consider more common explanations before suspecting HLH.

Hemophagocytosis-Related (Asian Variant) Intravascular Large B-Cell Lymphoma in a Hispanic Patient: A Case Report Highlighting a Micronodular Pattern in the Spleen

OBJECTIVES

We report a case of hemophagocytosis-related (Asian variant) intravascular large B-cell lymphoma (IVLBCL) in a patient of Western origin initially diagnosed by splenectomy with diffuse large B-cell lymphoma (DLBCL) with a micronodular pattern. The clonal relationship between these two DLBCL subtypes is also investigated.

METHODS

Hemophagocytosis-related (Asian variant) IVLBCL was identified at autopsy in a 62-year-old Hispanic woman, in North America, following an antemortem diagnosis of massive splenic involvement by DLBCL with a micronodular pattern, a feature not expected of IVLBCL.

RESULTS

These two apparently distinct lymphoma types demonstrated similar immunophenotypic profiles and IgH gene rearrangements of identical size suggesting a clonal relationship. The 2008 WHO classification system describes IVLBCL in the spleen as having a sinusoidal pattern.

CONCLUSIONS

Our observations provide the first molecular genetic support for a seemingly underrecognized micronodular pattern of IVLBCL in the spleen and further support the proposal of a "mixed variant" of IVLBCL with concomitant "intravascular" and "solid" phases of disease.

Cation-exchange high-performance liquid chromatography for variant hemoglobins and HbF/A2: What must hematopathologists know about methodology?

Cation-exchange high-performance liquid chromatography (CE-HPLC) is a widely used laboratory test to detect variant hemoglobins as well as quantify hemoglobins F and A2 for the diagnosis of thalassemia syndromes. It’s versatility, speed, reproducibility and convenience have made CE-HPLC the method of choice to initially screen for hemoglobin disorders. Despite its popularity, several methodological aspects of the technology remain obscure to pathologists and this may have consequences in specific situations. This paper discusses the basic principles of the technique, the initial quality control steps and the interpretation of various controls and variables that are available on the instrument output. Subsequent sections are devoted to methodological considerations that arise during reporting of cases. For instance, common problems of misidentified peaks, totals crossing 100%, causes of total area being above or below acceptable limits and the importance of pre-integration region peaks are dealt with. Ultimately, CE-HPLC remains an investigation, the reporting of which combines in-depth knowledge of the biological basics with more than a working knowledge of the technological aspects of the technique.

The Expanding Spectrum of Follicular Lymphoma

Follicular lymphoma is a far more heterogeneous entity than originally appreciated. Clinical and biological variants are increasingly more granularly defined, expanding the spectrum of disease. Some variants associate with age, whereas others with anatomic site. Identification of these biologically distinct diseases has real prognostic and predictive value for patients today and likely will be more relevant in the future. Understanding of follicular lymphoma precursors has also made their identification both scientifically and clinically relevant. This review summarizes the features and understanding of follicular lymphoma, variants, and precursor lesions.

Extranodal Rosai-Dorfman Disease: Clinicopathologic Series of 10 Patients With Radiologic Correlation and Review of the Literature

OBJECTIVES

To describe the radiologic and clinicopathologic features of extranodal Rosai-Dorfman disease (RDD) in our patient population.

METHODS

Via a data mining engine, we evaluated 13 cases of extranodal RDD in 10 patients treated at our institution from 2000 to 2014.

RESULTS

There was a marked female predominance (90%) in our series. The most common clinical presentation was a palpable, painless mass, which often simulated a neoplasm. Only two cases occurred in children. Multicentric and recurrent disease were uncommon. Histologically, all cases showed large histiocytes with emperipolesis in a mixed inflammatory background, with areas of dense, storiform collagen fibrosis. Positive S-100 and CD68 with negative CD1a in histiocytes are characteristic.

CONCLUSIONS

Extranodal RDD is rare and its manifestations varied. It may constitute a clinical and pathologic diagnostic challenge. Clinical suspicion and recognition of its histologic features are necessary for correct diagnosis and avoiding unnecessary treatment. Resection is curative in most cases.

Oligoclonal Bands of Immunoglobulins in Serum Leading to Diagnosis of Human Immunodeficiency Virus 1 Infection

OBJECTIVES

To present a unique case where detection of oligoclonal bands in serum led to the diagnosis of human immunodeficiency virus (HIV) infection.

METHODS

A 64-year-old man treated for hypertension for 11 years had laboratory tests ordered by his primary care physician, including serum protein electrophoresis (SPE) and serum immunofixation electrophoresis.

RESULTS

The total protein serum protein concentration was elevated at 9.6 g/dL. The SPE showed an oligoclonal pattern of multiple discrete bands in the γ region; the concentration of one band was approximately 1 g/dL and that of two bands was approximately 0.5 g/dL each, with multiple smaller overlapping bands at approximately 0.1 g/dL each. All fractions by SPE were within reference intervals except for the γ fraction, which was elevated at 3.4 g/dL. The IFE demonstrated that this oligoclonal pattern was a mixture of multiple bands of immunoglobulin G (IgG)-λ and IgG-κ. The patient's HIV-1 antibody screen and HIV-1 Western blot were positive on three subsequent visits with strongly positive HIV-1 antibody index values of more than 50 (cutoff value of 1.0 for reactivity).

CONCLUSIONS

The etiology of HIV-associated clonal immunoglobulin bands is hypothesized to result from chronic antigenic stimulation leading to B-cell hyperplasia. In this regard, hypergammaglobulinemia is a well-known consequence of HIV infection due to B-cell activation, associated with paraproteins, and can be seen at any stage of the disease.

Diagnostic Utility of Flow Cytometry Analysis of Reactive T Cells in Nodular Lymphocyte-Predominant Hodgkin Lymphoma

OBJECTIVES

This study aims to define the diagnostic utility of flow cytometric features of T cells in nodular lymphocyte-predominant Hodgkin lymphoma (NLPHL).

METHODS

Cases were retrospectively identified based on diagnosis with NLPHL (n = 30 samples), classic Hodgkin lymphoma (CHL; n = 33), and reactive lymphoid hyperplasia (RLH; n = 43). Pathology slides were reviewed. Flow cytometry list mode data were reanalyzed.

RESULTS

The mean proportion of CD4 + CD8 + T cells (8.4%) in cases of NLPHL was significantly higher than seen in CHL (1.0%) or RLH (0.6%). Of the T cells, 28.4% were CD57 + in NLPHL, significantly higher (P < .05) than in CHL (3.2%) or RLH (3.2%). Based on receiver operating characteristic curve analysis, when using a cutoff of 3.0% of CD4 + CD8 + T cells, the diagnostic sensitivity for NLPHL is 83.3% with a specificity of 97.4%. The diagnostic sensitivity was 96.7% with a specificity of 98.7% when using a cutoff of 12% for CD57 + T cells.

CONCLUSIONS

Increased portions of CD57 + T cells and CD4 + CD8 + T cells are highly suggestive of the possibility of NLPHL. In addition, NLPHL diagnosis appears unlikely if neither CD57 + T cells nor CD4 + CD8 + T cells are increased. Future prospective studies including cases of progressive transformation of germinal center and T-cell/histiocyte-rich large B-cell lymphoma will further define the utility of flow cytometry of T cells in NLPHL.

Acute Myeloid Leukemia With Recurrent Genetic Abnormalities Other Than Translocations

OBJECTIVES

Session 2 of the workshop focused on cases of acute myeloid leukemia (AML) with gene mutations in the setting of a normal karyotype.

METHODS

Among 22 AML cases submitted, 14 had the NPM1 mutation, most also accompanied by mutations of other genes such as FLT3-ITD, DNMT3A, or, rarely, TP53; three cases had the heterozygous CEBPA mutation; and two cases had MYC amplification.

RESULTS

We explored prognostic implications of gene mutations such as DNMT3A, issues related to the classification of AML cases with the NPM1 mutation, and myelodysplasia-related changes arising from chronic myelomonocytic leukemia after a short latency interval. Disparate patterns of treatment response to targeted therapy using an FLT3 inhibitor, designated as cytotoxic or differentiation, and their genetic underpinnings were described. Finally, a minimal screening panel for gene mutations and the optimal approach for monitoring minimal residual disease were discussed.

CONCLUSIONS

In aggregate, this session highlighted the need for a refined molecular classification of AML as well as improved risk stratification based on systematic assessment for genetic alterations and their evolution over time.

Cytogenetic Variation of B-Lymphoblastic Leukemia With Intrachromosomal Amplification of Chromosome 21 (iAMP21): A Multi-Institutional Series Review

OBJECTIVES

B-lymphoblastic leukemia (B-ALL) with intrachromosomal amplification of chromosome 21 (iAMP21) is a relatively uncommon manifestation of acute leukemia and limited predominantly to the pediatric population. Case-specific information regarding flow cytometric, morphologic, and laboratory findings of this subtype of leukemia is currently lacking.

METHODS

We searched the databases of three large institutions for lymphoblastic leukemia with iAMP21 from 2005 through 2012 and analyzed the clinicopathologic features.

RESULTS

We identified 17 cases with five or more RUNX1 signals on interphase nuclei, 14 of which were consistent with the Children's Oncology Group (COG) definition for iAMP21—namely, the presence of three or more RUNX1 signals on one marker chromosome. These cases showed a statistically significant lower peripheral WBC count and older age at diagnosis compared with all pediatric cases of B-ALL. We also identified three cases with increased RUNX1 signals scattered on multiple marker chromosomes that did not meet the COG definition of iAMP21 but showed similar 21q instability and older age at presentation.

CONCLUSIONS

Our findings not only demonstrate that B-ALL with iAMP21 is truly a distinct clinicopathologic entity but also suggest that a subset of cases of B-ALL with iAMP21 can show variable cytogenetic features.

Conventional karyotyping and fluorescence in situ hybridization: an effective utilization strategy in diagnostic adult acute myeloid leukemia

OBJECTIVES

Cytogenetics defines disease entities and predicts prognosis in acute myeloid leukemia (AML). Conventional karyotyping provides a comprehensive view of the genome, while fluorescence in situ hybridization (FISH) detects targeted abnormalities. The aim of this study was to compare the utility of karyotyping and FISH in adult AML.

METHODS

We studied 250 adult AML cases with concurrent karyotyping and FISH testing. Karyotyping was considered adequate when 20 or more metaphases were analyzed.

RESULTS

In total, 220 cases had adequate karyotyping and were classified as normal karyotype/normal FISH (n = 92), normal karyotype/abnormal FISH (n = 4), abnormal karyotype/normal FISH (n = 8), and abnormal karyotype/abnormal FISH (n = 116). The overall karyotype/FISH concordance rate was 97.7% with five discordant cases identified, four from the normal karyotype/abnormal FISH group and one from the abnormal karyotype/abnormal FISH group. No karyotype/FISH discordance was seen in the abnormal karyotype/normal FISH group for the FISH probes evaluated. FISH lent prognostic information in one (0.5%) of 220 cases with normal karyotype/abnormal FISH: CBFB-MYH11 fusion, indicating favorable prognosis.

CONCLUSIONS

In adult AML, FISH rarely provides additional information when karyotyping is adequate. We therefore propose an evidence-based, cost-effective algorithmic approach for routine conventional karyotype and FISH testing in adult AML workup.

A case series of clinically undiagnosed hematopoietic neoplasms discovered at autopsy

OBJECTIVES

In the United States, autopsy rates have diminished to less than 5% during the last half of the 20th century and the beginning of the 21st century for a multitude of reasons. Many believe this results in unrecognized malignancies that could have explained a patient's death.

METHODS

We describe six deaths in which hematopoietic neoplasms were identified at autopsy but were not diagnosed clinically.

RESULTS

The six undiagnosed hematopoietic malignancy cases discovered at autopsy include four men and two women ranging from 50 to 78 years of age. One patient was African American and five patients were white, all with multiple comorbidities. The tumors included diffuse large B-cell lymphoma, activated B-cell type, intravascular large B-cell lymphoma, ALK-negative anaplastic large cell lymphoma arising in a setting of human immunodeficiency virus, and a myeloid sarcoma.

CONCLUSIONS

These cases illustrate the importance of the traditional postmortem examination in not only confirming clinical diagnoses but also identifying previously unknown diagnoses. Hematologic malignancies may present with nonspecific clinical manifestations, and this series of cases also emphasizes the necessity for widening the differential diagnosis in patients with unexplained lactic acidosis and hepatic failure to include hematopoietic malignancies since prompt treatment may be lifesaving.

Lymphoplasmacytic lymphoma and marginal zone lymphoma in the bone marrow: paratrabecular involvement as an important distinguishing feature

OBJECTIVES

The differential diagnosis between bone marrow involvement by lymphoplasmacytic lymphoma (LPL) and marginal zone lymphoma (MZL) is challenging because histology and immunophenotype of both diseases overlap. We revisited the diagnostic pathology features of both diseases in the bone marrow.

METHODS

We studied a series of bone marrow trephine biopsy specimens from 59 patients with Waldenström macroglobulinemia without extramedullary involvement and bone marrow biopsy specimens from 23 patients with well-characterized MZL who also had bone marrow involvement. H&E- and immunoperoxidase-stained sections of bone marrow trephine biopsy specimens as well as flow cytometry and classic cytogenetics performed on aspirations were reviewed. The study was complemented with MYD88 L265P mutation analysis of all samples.

RESULTS

The most distinguishing features of LPL with respect to MZL were focal paratrabecular involvement (P < .001), the presence of lymphoplasmacytoid cells (P < .001) and Dutcher bodies (P < .001), increased numbers of mast cells (P < .001), and the MYD88 L265P mutation (P < .001).

CONCLUSIONS

LPL can be reliably distinguished from MZL in the bone marrow by using a combination of pathology characteristics. Our findings stress the diagnostic importance of using the combination of the following parameters for a correct LPL diagnosis: paratrabecular infiltration, the presence of lymphoplasmacytoid cells and cells with Dutcher bodies, and an increased number of mast cells in addition to the presence of MYD88 mutation.

Flow cytometric identification of immunophenotypically aberrant T-cell clusters on skin shave biopsy specimens from patients with mycosis fungoides

OBJECTIVES

To assess the ability of flow cytometry (FC) to detect putative neoplastic T-cell subsets on skin shave biopsy (SSB) specimens from patients with mycosis fungoides (MF) and to study the immunophenotype of skin-infiltrating tumor cells in MF.

METHODS

SSB specimens from patients with suspected MF were bisected and submitted for both FC and routine histopathology. Six-dimensional gating strategies were applied to identify putative neoplastic cells, independently from their expected immunophenotype.

RESULTS

Aberrant T cells were detected by FC in 18 of 33 SBB specimens, of which all had clinicomorphologic features of MF. Of the remaining 15 SSB specimens, six had clinicomorphologic features of MF and nine were diagnosed with benign inflammatory dermatoses. Unexpectedly, CD26 was aberrantly overexpressed in 11 (73%) and lost in three (20%) of 15 SSB specimens from patients with MF where this antigen was evaluated. Other detected aberrancies included CD3 dim- (13/18 [72%]), CD7 dim- (15/18 [83%]), and CD4-/CD8- (3/18 [17%]).

CONCLUSIONS

FC is capable of identifying putative neoplastic cells on SSB specimens from patients with MF. Bright homogeneous CD26 expression is a common and previously undescribed immunophenotypic aberrancy on MF skin infiltrates.

Morphoproteomics identifies constitutive activation of the mTORC2/Akt and NF-κB pathways and expressions of IGF-1R, Sirt1, COX-2, and FASN in peripheral T-cell lymphomas: pathogenetic implications and therapeutic options

BACKGROUND

Gaining a better understanding of the molecular circuitries and pathways implicated in the malignant growth and biological behavior of T cell lymphomas may identify potential cellular targets with clinical therapeutic potential. The immunohistochemical characterization of key cellular proteins participating in these pathways can provide surrogate markers of biological activity. The mammalian target of rapamycin complex (mTORC) signaling pathway has been implicated in T-cell lymphopoiesis. The mTORC2 pathway involves downstream activation of nuclear factor (NF)-κB and p-Akt (Ser 473). Fatty acid synthase (FASN) and insulin-like growth factor-1 receptor (IGF-1R) are expressed upstream of the mTORC and NF-κB signaling pathways. Cyclooxygenase (COX)-2 products influence these pathways. Our goal was to use morphoproteomics to characterize the expression patterns of the proteins in various peripheral T-cell lymphomas.

DESIGN

Ten cases of peripheral T-cell lymphoma (PTCL) were examined for expression of proteins along the mTORC, Akt and NF-κB pathways and affiliated tumorigenic molecules. These included two angioimmunoblastic PTCL, one natural killer/PTCL, one anaplastic large PTCL, and six PTCL not otherwise specified. Immunostaining for phosphorylated (p) mTOR (Ser 2448), p-Akt (Ser 473), p-NF-κBp65 (Ser 536), IGF-1R (Tyr1165/1166), silent mating type information regulation 2 homolog 1 (Sirt1), COX-2 and FASN was performed on paraffin-embedded tissue for each case. Percent expression was scored using bright-field microscopy with high expression designated as more than 50% of the cells with positive stain in the appropriate subcellular compartment.

RESULTS

All ten cases demonstrated nuclear staining for p-mTOR (Ser 2448) corresponding to mTORC 2, and all cases showed strong, diffuse nuclear staining for p-NF-κBp65 (Ser 536). All ten also showed nuclear and cytoplasmic staining for p-Akt (Ser 473) and cytoplasmic staining for IGF-1R. High expressions for nuclear Sirt1, and cytoplasmic COX-2 and FASN were detected in 7, 9, and 8 out of 10 cases, respectively. Six out of 10 cases demonstrated high expression of all the mentioned markers.

CONCLUSION

The constitutive activation of mTORC2, NF-κB, p-Akt and the concomitant expression of IGF-1R suggests convergence of these molecular pathways in T-cell lymphoma. The results of this study also suggest that mTORC2 may be a common denominator among this heterogeneous group of lymphomas. Interference of key nodes of this pathway may carry a clinical therapeutic benefit. Agents that may be considered based on existing data include: bortezomib to inhibit NF-κB pathway activation; metformin to inhibit both NF-κB and mTORC2 and histone deacteylase inhibitors to inhibit mTORC2 pathway signaling. Furthermore, panobinostat inhibits Sirt1 pathway when present, and celecoxib inhibits NF-κB pathway activation independent of COX2.

Web-based oil immersion whole slide imaging increases efficiency and clinical team satisfaction in hematopathology tumor board

Background:

Whole slide imaging (WSI) is widely used for education and research, but is increasingly being used to streamline clinical workflow. We present our experience with regard to satisfaction and time utilization using oil immersion WSI for presentation of blood/marrow aspirate smears, core biopsies, and tissue sections in hematology/oncology tumor board/treatment planning conferences (TPC).

Methods:

Lymph nodes and bone marrow core biopsies were scanned at ×20 magnification and blood/marrow smears at 83X under oil immersion and uploaded to an online library with areas of interest to be displayed annotated digitally via web browser. Pathologist time required to prepare slides for scanning was compared to that required to prepare for microscope projection (MP). Time required to present cases during TPC was also compared. A 10-point evaluation survey was used to assess clinician satisfaction with each presentation method.

Results:

There was no significant difference in hematopathologist preparation time between WSI and MP. However, presentation time was significantly less for WSI compared to MP as selection and annotation of slides was done prior to TPC with WSI, enabling more efficient use of TPC presentation time. Survey results showed a significant increase in satisfaction by clinical attendees with regard to image quality, efficiency of presentation of pertinent findings, aid in clinical decision-making, and overall satisfaction regarding pathology presentation. A majority of respondents also noted decreased motion sickness with WSI.

Conclusions:

Whole slide imaging, particularly with the ability to use oil scanning, provides higher quality images compared to MP and significantly increases clinician satisfaction. WSI streamlines preparation for TPC by permitting prior slide selection, resulting in greater efficiency during TPC presentation.