Diagnosis Of Plasma Cell Neoplasm Research Articles

A-173 Evaluation of Artificial Intelligence (AI)-assisted Flow Cytometry Analysis for Plasma Cell Neoplasms

Abstract Background Flow cytometry plays a critical role in diagnosing hematologic disorders, yet manual analysis is time-consuming and prone to variability. Significant advancements in artificial intelligence (AI) within healthcare have occurred in recent years. Previously, we developed and evaluated an AI-assisted automated system for diagnosing acute leukemia. This study aims to assess the effectiveness of the AI system in diagnosing plasma cell neoplasms. Methods A total of 76 bone marrow samples were analyzed using a panel of antibodies (CD38, CD56, CD138, Kappa, and Lambda) to determine plasma cell percentages and immunophenotype. All samples were used for initial diagnosis of plasma cell neoplasm or therapeutic monitoring. Manual analysis using Kaluza™ software served as the gold standard. The same flow cytometry data was processed by the AI software (DeepFlow™) for comparison. Pearson correlation coefficients were used to compare AI and manual analysis for diagnosis and plasma cell count. Results Among the 76 cases, manual analysis identified 57 positive cases for monoclonal plasma cells (36 cases of CD38+/CD138+/Kappa+ and 21 cases of CD38+/CD138+/Lambda+), with 89% showing aberrant CD56 expression. AI identified 49 monoclonal cases, missing 8 cases with low plasma cell levels (<0.07%) or brighter fluorescence. AI accurately matched 97% of immunophenotypes with manual analysis. Pearson correlation coefficients demonstrated excellent correlation (r=1.0) between manual and AI plasma cell percentages. Furthermore, AI has also enhanced laboratory efficiency, reducing analysis time per case from 10 minutes with manual methods to just 3 minutes with AI analysis. Conclusions This study shows promise for AI-assisted flow software in diagnosing plasma cell neoplasms. AI has enhanced operational efficiency by reducing the manual processing and analysis time. Further training is needed to improve the identification of variations in fluorescence intensity and low plasma cell levels.

Evaluation of a new technique using artificial intelligence for quantification of plasma cells on CD138 immunohistochemistry.

The diagnosis of plasma cell neoplasms depends on the accurate quantification of plasma cells, traditionally done by immunohistochemical CD138 staining of bone marrow biopsies. Currently, there is no fully satisfactory reference method for this quantification. In our previous study, we compared the commonly used overview estimation method (method A) with a novel method for counting plasma cells in three representative areas (method B). Results showed comparable concordance parameters between the two methods. In this follow-up study, we compared the previously evaluated methods with a digital analysis method (method C) that uses artificial intelligence in open-source software, QuPath. Archived CD138 immunohistochemically stained trephine sections of bone marrow samples used in our previous study were used (n = 33). Reviewers selected three representative areas on each sample by taking images with a light microscope and camera. Digital analysis was performed using the positive cell detection function in QuPath. The entire process was repeated by each reviewer to test intraobserver concordance (concordance correlation coefficient [CCC]) in addition to interobserver concordance (intraclass correlation coefficient [ICC]). Intraobserver concordance of method C showed strong agreement for all reviewers with the lowest CCC = 0.854. Interobserver concordance for method C using ICC was 0.909 and 0.949. This showed high interobserver agreement with significant differences between method C and previously assessed method A (ICC = 0.793 and 0.713) and method B (ICC = 0.657 and 0.658). We were able to successfully count CD138-positive plasma cells in bone marrow biopsies using artificial intelligence. This method is superior to both manual counting and overview estimation, regardless of tumour load.

Significance of bone marrow immunohistochemical analysis in patients with plasma cell neoplasms

Background. The group of plasma cell neoplasms includes benign and malignant diseases. Sometimes there are difficulties in making a diagnosis. The study of the diagnostic and prognostic significance of immunohistochemical (IHC) markers is of current interest.Aim. To study the significance of IHC markers and histological features of the bone marrow in primary diagnosis in patients with multiple myeloma (MM) and monoclonal gammopathy of undetermined significance (MGUS).Materials and methods. The study included 287 patients with plasma cell neoplasms: MGUS (n = 148), MM (n = 139). The observation period was 50 months. All patients have performed an aspiration biopsy and histological examination of the bone marrow with IHC analysis of CD138+, CD56+, CD34+, κ- and λ-chains expression.Results. During the observation period the progression of MGUS to MM was recorded in 8.8 % (n = 13) of cases, the progression of MM was determined in 38.1 % (n = 53) of cases.In patients with MGUS and MM the determined percentage of plasma cells at aspiration biopsy was somewhat lower than at histological examination (p >0.001). Statistically significant differences were determined between the groups MGUS and MM by the type of infiltration (р <0.001). With an increase in the percentage of bone marrow lesions by IHC (<20 % vs. 20–50 % and 20–50 % vs. >50 %), in our study interstitial and diffuse type of lesion with large accumulations was more common compared to the nodular type (p = 0.001).The CD138+ expression (IHC) more than 10 % was associated with a decrease of progression-free survival in patients with MGUS.In MM patients with an interstitial type of bone marrow infiltration and CD138+ over 10 % osteodestructive syndrome was detected by X-ray methods in 82.9 % of cases.Determination of CD56+ and immunoglobulin light chains expression in patients with MM and MGUS indicated an unfavorable prognosis.Resistance to chemotherapy or disease progression in MM patients most often occurred with a combination of IgG and immunoglobulin light chains secretion, with CD138+ plasma cells more than 50 % according to IHC, with a diffuse type of bone marrow lesion with accumulations of plasma cells. MGUS patients progressed more frequently with more than 20 % CD138+ plasma cells according to IHC, interstitial type and diffuse plasma cells accumulation type of bone marrow lesion, secretion of IgG or two immunoglobulins.Conclusion. The significance of the IHC study in the diagnosis of plasma cell neoplasms was confirmed. Markers associated with the disease progression and chemotherapy resistance in patients with MGUS and MM were identified.

Fine‐needle aspiration cytology for the diagnosis of plasma cell neoplasms in the head and neck region: A systematic analysis of the literature

Cytopathologic analysis is feasible and provides detailed morphological characterisation of head and neck lesions. To integrate the available data published on fine-needle aspiration cytology (FNAC) used for the diagnosis of plasma cell neoplasms (PCN) of the head and neck region. Searches on PubMed, Web of Science, Embase, and Scopus were performed to compile data from case reports/case series published in English. The Joanna Briggs Institute tool was used for the critical appraisal of studies. A total of 82 studies comprising 102 patients were included in this review. There was a predilection for men (68.6%) (male/female ratio: 2.1:1). Individuals in their 50s (29.4%), 60s (22.5%), and 70s (22.5%) were more often affected. The thyroid gland (26.2%) was the main anatomical location, followed by scalp (15.5%), neck/cervical region (15.5%), jaws (13.6%), and major salivary glands (13.6%). For FNAC analysis, a smear was employed in 41 (40.6%) cases and a cell block was used in four (3.9%). In 56 (55.4%) reports, no cytological methods were available. Morphologically, 34 (56.7%) cases had a diagnosis of PCN with agreement between cytopathology and histopathology. The rate of wrong diagnoses when using cytology was 27.5%. Immunophenotyping was performed in 49 (48%) of the cases. The 69-month disease-free survival rate was 60.2%, while the 27-month overall survival rate was 64.1%. This study reinforces that FNAC can be an ancillary tool in the first step towards the diagnosis of PCN of the head and neck region, especially when applying a cell block for cytological analysis.

A novel and robust approach to defining population-based reference ranges for a serum free light chain assay in a clinical laboratory

Abstract Serum protein electrophoresis and immunofixation are used to detect the presence of monoclonal heavy and light immunoglobulin chains for the diagnosis of plasma cell neoplasms (PCN). In conjunction, the Freelite® assay has been used to detect excess free kappa and lambda light chains produced by PCN, where the kappa:lambda free light chain ratio (KLR) serves as a surrogate marker of clonality and disease. The manufacturer-defined KLR reference range of 0.26-1.65 is used in internationally recognized criteria for PCN diagnosis and monitoring, and KLR results affect clinical decision making, disease categorization, and response assessment. Our laboratory has verified the manufacturer-defined Freelite® KLR reference range three times using healthy control sera since assay implementation in 2006. Despite this, high percentages of abnormal KLR have consistently been observed among immunofixation-defined monoclonal-negative specimens. We therefore retrospectively interrogated 48,012 serum free light chain clinical results reported at our institution between 2010-2020 by extracting results from our laboratory information system and analyzing population distributions using the R programming language. For all specimens, the distribution of KLR values was shifted towards the towards the upper limit of the manufacturer-defined reference range, indicating that it poorly describes both our monoclonal-negative and monoclonal-positive patient populations. Furthermore, >80% of monoclonal-negative specimens exhibited KLR above the median of the manufacturer-defined reference range (0.26-1.65), while 24% (1,226/5,057) unexpectedly exhibited KLR >1.65. We found that this phenomenon has been present consistently since 2010 and is not affected by patient sex or age, impaired renal function, lot-to-lot variation, or assay drift. We therefore sought to establish an institution-appropriate KLR reference range by defining a reference population from within our existing dataset. We leveraged International Classification of Diseases codes, estimated glomerular function data, and serum/urine immunofixation results to exclude specimens from individuals with PCN- or renal-related diagnoses, impaired renal function, and prior, current, or subsequent monoclonal components. The resultant 1,536 monoclonal-negative reference specimens were then classified according to the manufacturer-defined KLR reference range, where 13% remained abnormally elevated, consistent with the published false positive rate in healthy volunteers. Lastly, we determined a new KLR reference range of 0.66-2.21 using the central 95% of KLR values from these reference specimens. When applied to our dataset, this institution-specific KLR reference range improved the accurate classification of specimens containing monoclonal free light chains by immunofixation, while reducing the false-positive rate in monoclonal-negative specimens. Together, our findings support the use of historical KLR and immunofixation data from routine clinical testing to derive institution-appropriate KLR reference ranges, which can then be used for continuous quality improvement. Implementation of this more-accurate KLR reference range should improve subsequent test utilization by non-specialist providers, reduce concern for/over-diagnosis of kappa-involved disease, and improve the detection and monitoring of lambda-involved disease.

PSAT288 Mucosa-associated Lymphoid Tissue Thyroid Lymphoma Presenting as a Rapidly Growing Neck Mass in an Asymptomatic Male Patient

Abstract A 77-year-old male was referred to endocrinology for a 2-month history of a rapidly enlarging painless left neck mass. His only other complaint was unintentional weight loss of 10 pounds over 12-months. On exam patient had a firm, smooth, nontender 2 cm thyroid/neck mass extending below left clavicle. No abnormalities were detected for right thyroid gland. There was no palpable lymphadenopathies or hepatosplenomegaly noted. No signs of tracheal, esophageal, or neck vein compression were noted. He did not have any history of radiation exposure, family history of thyroid-related disorders, or malignancy. Laboratory test including complete blood count, comprehensive metabolic profile and TSH were within normal limits. TPO antibody was positive. Ultrasound revealed a 7.7×4.1×4 cm hypoechoic spongiform mass replacing the left lobe of the thyroid, as well as scattered sub centimeter nodules. Contrasted CT of the neck confirmed 6.5×5.2×3.9 cm left thyroid mass causing mild rightward deviation of the trachea and extending into the superior mediastinum and no lymphadenopathy. FNA of the mass revealed presence of crushed lymphoid cells without thyroid follicular cells, which raised the possibility of chronic lymphocytic thyroiditis. FDG- PET scan showed intense, heterogeneous FDG uptake in the left neck mass (max SUV=10.7), likely arising from the left thyroid lobe concerning for thyroid malignancy without evidence of distant metastases. The patient underwent a left thyroid nodule core biopsy with subsequent left thyroid hemithyroidectomy. The pathology stains of the excised left thyroid lobe core biopsy showed extra nodal zone lymphoma of mucosa- associated lymphoid tissue (MALT Lymphoma) with extensive plasmocytic differentiation. Surgical path confirmed extra nodal zone lymphoma of mucosa-associated lymphoid tissue (MALT Lymphoma) with extensive plasmocytic differentiation and foci of chronic lymphocytic thyroiditis. Immunochemistry studies supported a diagnosis of plasma cell neoplasm or the plasma cell component of a B-cell lymphoproliferative disorder. Short-term follow-up FDG-PET and CT imaging demonstrated post-surgical changes without evidence of recurrence. Presentation: Saturday, June 11, 2022 1:00 p.m. - 3:00 p.m.

A Novel Integrated Approach for Cytogenomic Evaluation of Plasma Cell Neoplasms

Plasma cell neoplasm (PCN) is associated with characteristic chromosomal aberrations of diagnostic and prognostic significance. The presence of a small percentage of neoplastic cells is a drawback in the application of karyotyping and fluorescence in situ hybridization for the evaluation of bone marrow aspirate. The analysis of samples enriched for CD138+ cells has improved the detection rate. However, fluorescence in situ hybridization requires several probes and may not be completed due to a limited number of isolated cells. To address the issues experienced with the conventional approach, a novel integrated protocol that consists of whole-genome amplification of DNA isolated from CD138+ cells, followed by microarray as well as one fluorescence in situ hybridization assay for balanced IGH gene rearrangements, has been developed. In the present study in a cohort of 56 patients with clinical suspicion for PCN, compared to conventional cytogenetic analysis, this approach provided higher yield in the detection of PCN-related abnormalities, irrespective of the initial percentage of plasma cells. Whole-genome profiling uncovered recurrent chromosomal abnormalities of prognostic value, including unbalanced alterations within the MYC locus, 16q loss, and hypodiploidy, that were not otherwise detectable by conventional methods. The proposed approach is cost-efficient and provides a superior detection rate, required for proper risk stratification and differential diagnosis of PCN regardless of initial plasma cell percentage.

The Prevalence of Epstein-Barr Virus in Plasma Cell Neoplasms is Higher in HIV-Positive Individuals.

Epstein-Barr virus (EBV) is causally associated with many hematolymphoid malignancies. This laboratory-based study aimed to establish the prevalence of EBV in plasma cell neoplasms in a large South African cohort and to determine whether there is any correlation between EBV-positivity and human immunodeficiency virus (HIV) status in patients with plasma cell neoplasms, including plasma cell myeloma and plasmacytoma (solitary plasmacytoma of bone and extraosseous plasmacytoma). This single-institution retrospective study included all patients with a histopathologic diagnosis of plasma cell neoplasm between 2003 and 2020. EBV-expression in the plasma cell neoplasms was assessed by EBV-encoded RNA (EBER) in situ hybridization (ISH) and correlated with HIV status. HIV status was determined by retrieving prior serologic results. Formalin-fixed paraffin-embedded tissue from HIV-unknown patients underwent HIV-1 p24 antibody testing. Sixteen of 89 plasma cell neoplasms (18%) were EBV-positive. There was a significant correlation between EBV and HIV infection in plasma cell neoplasms, with 6/10 tumors from HIV positive patients showing EBV-positivity in tumor cells. The EBV-positive cohort was significantly younger than the EBV-negative group. EBV-positivity in plasma cell neoplasms in this study is higher than previously reported. The significant occurrence of EBV in plasma cell neoplasms from HIV-positive patients suggests a co-carcinogenic relationship between the two viruses.

Deep Learning Accurately Quantifies Plasma Cell Percentages on CD138-Stained Bone Marrow Samples

The diagnosis of plasma cell neoplasms requires accurate, and ideally precise, percentages. This plasma cell percentage is often determined by visual estimation of CD138-stained bone marrow biopsies and clot sections. While not necessarily inaccurate, estimates are by definition imprecise. For this study, we hypothesized that deep learning can be used to improve precision. We trained a semantic segmentation-based convolutional neural network (CNN) using annotations of CD138+ and CD138- cells provided by one pathologist on small image patches of bone marrow and validated the CNN on an independent test set of image patches using annotations from two pathologists and a non-deep learning commercial software. On validation, we found that the intraclass correlation coefficients for plasma cell percentages between the CNN and pathologist #1, a non-deep learning commercial software and pathologist #1, and pathologists #1 and #2 were 0.975, 0.892, and 0.994, respectively. The overall results show that CNN labels were almost as accurate as pathologist labels at a cell-by-cell level. Once satisfied with performance, we scaled-up the CNN to evaluate whole slide images (WSIs), and deployed the system as a workflow friendly web application to measure plasma cell percentages using snapshots taken from microscope cameras.

Multiple myeloma from the pathologist's perspective

Multiple myeloma (MM) is one of the most common hematological neoplasms and accounts for approximately 1% of human cancers. Description of current diagnostics and classification of MM and related plasma cell neoplasms from the pathology viewpoint. Current knowledge regarding pathology and genetics of MM is summarized and tissue-based diagnostics following international consensus classifications and the current S3 guideline are described. MM and related neoplasms are composed of malignant plasma cells that secrete amonoclonal immunoglobulin, which is an important parameter of disease activity. MM shows amultistage development. Almost all cases are preceded by aclinically inapparent precursor lesion, monoclonal gammopathy of undetermined significance (MGUS), which can progress to smoldering myeloma with ahigher tumor burden, but absence of organ damage. Systemic MM needs to be discerned from the localized forms, solitary osseous and primary extramedullary plasmacytoma. MM is genetically very heterogeneous and can be broadly subdivided into two cytogenetic groups, cases with primary IGH translocations and cases with hyperdiploidy. Intratumoral genetic heterogeneity is frequently pronounced and correlates with the size of focal lesions in imaging. Diagnosis of plasma cell neoplasms is done according to the criteria of the International Myeloma Working Group (IWMG) and requires interdisciplinary evaluation of clinical, serological, pathological and radiological features. In addition to clinical parameters, molecular markers, especially cytogenetic aberrations, are of great prognostic relevance.

Central Nervous System Involvement

Extramedullary involvement in multiple myeloma (MM) is seen in 7%–18% of cases. The common organs involved are skin and upper respiratory tract. The uncommon organs involved include the liver, spleen, kidney, pleura, lymph nodes, and soft tissue. Central nervous system (CNS) involvement is extremely rare and occurs in only about 1% of patients. We present an interesting case of nonsecretory MM (NSMM) with atypical involvement of the liver, spleen and CNS. An elderly female patient initially presented with low backache. Skeletal survey showed multiple lytic bony lesions. An initial diagnosis of plasma cell neoplasm was made based on the biopsy of the sacral lytic lesion. No monoclonal gammopathy was found in the serum or urine electrophoresis. A diagnosis of NSMM was made and the patient was started on bortezomib, dexamethasone, lenalidomide (VRD regime). However, over the next 2 months or so, the patient was found to have involvement of liver, spleen, and meninges on imaging despite chemotherapy. The plasmablastic lesions were confirmed on liver biopsy, bone marrow, and cerebral spinal fluid study. Patient showed remarkable clinical improvement on addition of daratumumab to the VRD regime and is currently under maintenance therapy. Repeat imaging shows the reduction in lytic lesions. This case is reported as a rare combination of NSMM with CNS involvement.

Clinical Utility of B- and T-Cell Gene Rearrangement Studies in Blood and Bone Marrow Samples

In the evaluation of bone marrow (BM) and peripheral blood (PB) for hematologic malignancy, positive immunoglobulin heavy chain (IG) or T-cell receptor (TCR) gene rearrangement results may be detected despite unrevealing results from morphologic, flow cytometric, immunohistochemical (IHC), and/or cytogenetic studies. The significance of positive rearrangement studies in the context of otherwise normal ancillary findings is unknown, and as such, we hypothesized that gene rearrangement studies may be predictive of an emerging B- or T-cell clone in the absence of other abnormal laboratory tests. Data from all patients who underwent IG or TCR gene rearrangement testing at the authors' affiliated VA Hospital between January 1, 2013 and July 6, 2018 were extracted from the electronic medical record. Date of testing; specimen source; and morphologic, flow cytometric, IHC, and cytogenetic characterization of the tissue source were recorded from pathology reports. Gene rearrangement results were categorized as true positive, false positive, false negative, or true negative. Lastly, patient records were reviewed for subsequent diagnosis of hematologic malignancy in patients with positive gene rearrangement results with negative ancillary testing. A total of 136 patients, who had 203 gene rearrangement studies (50 PB and 153 BM), were analyzed. In TCR studies, there were 2 false positives and 1 false negative in 47 PB assays, as well as 7 false positives and 1 false negative in 54 BM assays. Regarding IG studies, 3 false positives and 12 false negatives in 99 BM studies were identified. Sensitivity and specificity, respectively, were calculated for PB TCR studies (94% and 93%), BM IG studies (71% and 95%), and BM TCR studies (92% and 83%). Analysis of PB IG gene rearrangement studies was not performed due to the small number of tests (3; all true negative). None of the 12 patients with false positive IG/TCR gene rearrangement studies later developed a lymphoproliferative disorder, although two patients were later diagnosed with acute myeloid leukemia. Of the 14 false negatives, 10 (71%) were related to a diagnosis of plasma cell neoplasms. Results from the present study suggest that positive IG/TCR gene rearrangement studies are not predictive of lymphoproliferative disorders in the context of otherwise negative BM or PB findings. As such, when faced with equivocal pathology reports, clinicians can be practically advised that isolated positive IG/TCR gene rearrangement results may not indicate the need for closer surveillance. Disclosures No relevant conflicts of interest to declare.

Evaluation of Positive T- and B-Cell Gene Rearrangement Studies Among Patients Without a Definitive Diagnosis by Other Assays

Abstract In the evaluation of bone marrow (BM) and peripheral blood (PB) for hematologic malignancy, positive immunoglobulin heavy chain (IG) or T-cell receptor (TCR) gene rearrangement results may be detected despite unrevealing results from morphologic, flow cytometric, immunohistochemical (IHC), and/or cytogenetic studies. The significance of positive rearrangement studies in the context of otherwise normal ancillary findings is unknown, and as such, we hypothesized that gene rearrangement studies may be predictive of an emerging B- or T-cell clone in the absence of other abnormal laboratory tests. Data from all patients who underwent IG or TCR gene rearrangement testing at the authors’ affiliated VA hospital between January 1, 2013, and July 6, 2018, were extracted from the electronic medical record. Date of testing; specimen source; and morphologic, flow cytometric, IHC, and cytogenetic characterization of the tissue source were recorded from pathology reports. Gene rearrangement results were categorized as true positive, false positive, false negative, or true negative. Lastly, patient records were reviewed for subsequent diagnosis of hematologic malignancy in patients with positive gene rearrangement results with negative ancillary testing. A total of 136 patients, who had 203 gene rearrangement studies (50 PB and 153 BM), were analyzed. In TCR studies, there were 2 false positives and 1 false negative in 47 PB assays, as well as 7 false positives and 1 false negative in 54 BM assays. Regarding IG studies, 3 false positives and 12 false negatives in 99 BM studies were identified. Sensitivity and specificity, respectively, were calculated for PB TCR studies (94% and 93%), BM IG studies (71% and 95%), and BM TCR studies (92% and 83%). Analysis of PB IG gene rearrangement studies was not performed due to the small number of tests (3; all true negative). None of the 12 patients with false-positive IG/TCR gene rearrangement studies later developed a lymphoproliferative disorder, although 2 patients were later diagnosed with acute myeloid leukemia. Of the 14 false negatives, 10 (71%) were related to a diagnosis of plasma cell neoplasms. Results from the present study suggest that positive IG/TCR gene rearrangement studies are not predictive of lymphoproliferative disorders in the context of otherwise negative BM or PB findings. As such, when faced with equivocal pathology reports, clinicians can be practically advised that isolated positive IG/TCR gene rearrangement results may not indicate the need for closer surveillance.

Flow Cytometric Immunophenotypic Analysis in the Diagnosis and Prognostication of Plasma Cell Neoplasms.

This review focuses on the roles of flow cytometric immunophenotyping has in the differential diagnosis of plasma cell neoplasms and the post-therapy monitoring of minimal (measurable) residual disease. The need to integrate flow cytometry data with clinical, laboratory, radiographic, morphological, and molecular genetic findings is emphasized. The challenges of and strategies for evaluating plasma cells in the setting of targeted therapy are also highlighted. © 2019 International Clinical Cytometry Society.

Reactivity with the EpCAM-specific antibodies MOC-31 and Ber-Ep4 in plasma cell neoplasms: a potential diagnostic pitfall in cytology samples

Epithelial cell adhesion molecule (EpCAM) is a protein expressed on surfaces of healthy epithelia, and is overexpressed in dysplasias and carcinomas. Immunohistochemistry (IHC) utilizing antibodies that react with EpCAM, such as MOC-31 and Ber-EP4, distinguish reactive mesothelial cells from carcinomas in serous effusions. IHC is crucial in effusions with singly dispersed atypical cells, a scenario with a broad differential, including hematopoietic malignancies. Plasma cell neoplasms (PCN) are the second most common hematopoietic malignancy, manifesting as multiple myeloma or plasmacytoma, with 6% of cases developing serous cavity involvement. Most PCNs are readily recognizable; however, variants that deviate from the classic cytomorphology risk erroneous diagnosis. This study demonstrates EpCAM expression in a subset of PCNs, highlighting a potential diagnostic pitfall in serous effusion cytology. A 10-year retrospective search for cytology specimens with a diagnosis of PCN was performed. All cases demonstrating CD138/CD38 and monoclonal immunoglobulin expression, and adequately cellular cell block were included. IHC analysis for MOC-31 and Ber-EP4 was performed using Ventana Benchmark Ultra. Scoring was performed as follows: total IHC score equals the positive proportion (0 = no positive tumor cells; 1 = <1%; 2 = 1-10%; 3 =11-33%; 4 = 34-66%; 5 = 67-100%) plus staining intensity (0, no staining; 1, weak; 2, moderate; 3, strong). A score > 4 was considered positive. 2 of 28 (7%) PCNs demonstrated positivity for MOC-31 and Ber-Ep4. A subset of PCNs in cytology samples show positivity for MOC-31 and Ber-EP4 which could result in misinterpretation as carcinoma.

High and Low Tumor Infiltration Affect the Differences Among the Detection of Plasma Cells Evaluated in Bone Marrow By Flow Cytometry, Aspirate and Biopsy(Grupo Interdisciplinario de Mieloma Multiple, Hospital Universitario Fundacion Santa Fe, Colombia)

BackgroundIn plasma cell neoplasms, the percentage of plasma cells in bone marrow (PPCBM) is important for diagnosis and assessment of the treatment. This quantification is performed using bone marrow multiparameter flow cytometry (FC), aspirate smears (BMA) and biopsy. Differences among the percentage of infiltration detected by these techniques have been reported, which can be related to a heterogeneous pattern of infiltration of multiple myeloma (MM) or sample quality. However, a simultaneous evaluation of these three techniques has not been reported nor their ability to detect bone marrow involvement with high or low infiltration, associated with different stages of this disease.PurposeThe aim of this study was to compare the results of PPCBM obtained by FC, BMA, and biopsy with CD138 immunohistochemistry (BMB) in different stages of the disease with high and low infiltration, and the ability of these techniques to correctly classify the disease.MethodsPathological studies of patients referred to Hospital Fundación Santa Fe, Colombia were reviewed between January 2015 and June 2018. The selection of patients was based on both, a diagnosis of plasma cell neoplasms, classified according to the International Myeloma Working Group criteria and the simultaneous use of FC by FACSCanto II flow cytometer (Infinicyt 2.0 software program), wright-stained aspirate smears and biopsy with CD138 immunohistochemistry in the detection.Descriptive analysis was performed and PPCBM was expressed as the mean± standard error of the mean (SEM). The Kruskal-Wallis test was used to compare the mean of PPCBM among the three methods. Lineal regression and Spearman´s coefficient were used to correlate the variables. Statistical association was considered significant for p values <0.05.ResultsA total of 130 patients with plasma cells neoplasms were included in this study, 57 with newly diagnosed MM (N), 58 following therapy MM (F) and 15 MGUS patients. In the N patients, the mean of infiltration was 12.3% ±1.8, 30.3% ±3.4 and 52.2% ±3.74 detected by FC, BMA and BMB, respectively. The PPCBM detected by this three analysis were significantly different (p<0.001). In F patients, the mean of infiltration was 0.37% ±0.05, 1.88 % ±0.16 and 2.61% ±0.21 while in MGUS-patients was 0.49% ±0.09, 2.067 % ±0.37 and 2.4% ±0.28 detected by FC, BMA and BMB, respectively. For F and MGUS patients, significant statistic differences between BMB and BMA versus FC (p<0.01) were observed, but not between BMB and BMA (Figure 1).In the comparative analysis of the three methods in all patients, the highest infiltration was always detected by BMB, followed by BMA and finally by FC (p<0.01) (Figure 2). Linear regression established that for each 1% of infiltration detected by FC or BMA, the BMB identified 2.11% and 1.4% of infiltration, respectively (Figure 2). However, each univariate model only explained 55% and 67% of the observed results. Notably, there was a high correlation among these three techniques (Spearman´s coefficient > 0.8).Finally, given that there are important PPCBM such as ≥10 that allows establishing the diagnosis of MM or ≥60%, considered an MM definitive event, we found that 21% and 52% of cases assessed by BMA and FC had PPCBM <10%, but all of them were reclassified as MM with BMB. None case had PCBM <10% using BMB. Finally, among all cases diagnosed as MM, there were identified 26 by FC and 35 cases by BMA with a PCBM percentage between 10 and 59%, of which 84% and 54% respectively had ≥60% of involvement detected by BMBConclusionIn the comparison of the PCBM was observed a high linear correlation between MFC, BMA, and BMB, although we found a differential behavior of these methods, depending on the level of tumor infiltration.High percentages of infiltration, such as newly diagnosed MM patients, the BMB detected significantly more PPCBM than the others two methods (1.7 to 4-fold compared to BMA and FC). This supports the systematic incorporation of BMB into the analysis of patients with suspected MM for allowing a proper classification of disease.With low percentages of infiltration, such as MGUS and following therapy patients, the difference of PPCBM between BMA and BMB was not significant. Although, FC detectedthe lowest percentage of infiltration, it known its high specificity to discriminate tumor and normal plasma cells, being in one of the most important analysis to monitor minimal residual. DisclosuresNo relevant conflicts of interest to declare.

14. A novel cytogenomic approach to diagnosis of plasma cell neoplasms

Plasma cell neoplasm (PCN) is characterized by specific chromosomal aberrations with diagnostic and prognostic significance. Low percentage of neoplastic cells is a drawback in application of karyotyping and fluorescence in situ hybridization (FISH) for evaluation of bone marrow aspirates. Enrichment techniques to isolate the CD138+ cells have improved the detection rates. However, a complete FISH analysis for various abnormalities may not be achieved due to limited number of isolated cells. In 2017, we validated and implemented a novel approach for a whole genome profiling of plasma cells in PCN. The protocol consisted of isolation of CD138+ cells, whole genome DNA amplification and microarray comparative genomic hybridization. Separate FISH analysis was performed for detection of balanced IGH rearrangements. Of 412 clinical cases to date, 234 (56.8%) had morphologic and immunohistochemical studies indicative of PCN with 0.5–90% plasma cells in a bone marrow aspirates. Among PCN patients, chromosomal abnormalities were identified in 223 (95.2%) demonstrated by both microarray and FISH (n = 76, 32.9%), microarray (n = 116, 50.2%) or FISH only (n = 31, 13.9%). The most common findings included IGH rearrangement (49%), 13q deletion (45%), hyperdiploidy (41%), and 1q duplication (38%). Tetraploidy and MYC rearrangements were observed in 2.1% (5/234) and 1.7% (4/234) of patients, respectively. Interestingly, microarray revealed characteristic deletions involving the 6q21q25 region in 4/7 patients with Waldenström Macroglobulinemia. Our diagnostic approach to PCN is a cost-efficient replacement of multiple FISH assays that provides a superior detection rate and additional information for disease classification, prognosis, treatment and differentiation from other B cell malignancies.

Mieloma múltiplo em uma cadela de 10 anos

Background: The malignant neoplasms, in general, constitute one of the main causes of death in dogs and cats. The multiple myeloma is a neoplasm characterized by the monoclonal proliferation of plasma cells in the bone marrow, causing several systemic symptoms and it is rare in pets, representing less than 1% of the malignant neoplasms in these animals. It usually occurs in older dogs. Thus, the purpose of this report was to describe a case of multiple myeloma in a 10-year-old poodle dog, occurred in the Veterinary Hospital Unit of the State University of Ceará.Case: A 10-year-old Poodle bitch was admitted in the Veterinary Hospital Unit of the State University of Ceará presenting lump erythematosus, alopecic, soft and ulcers in the region of the digits of the left front leg, pain and lameness. The blood count evidenced normocytic and normochromic anemia, presence of rouleaux, lymphopenia and monocytopenia, and the biochemical exams have demonstrated an elevated value of alanine aminotransferase (ALT). The cytology of the nodule indicated probable diagnosis of plasma cell neoplasm and radiographic examination showed the presence of bone lysis, and therefore the patient underwent amputation of the affected limb surgery. A biopsy of the nodule indicated neoplastic proliferation, with an arrange compatible to plasmacytoma of cleaved type. A follow-up consultation was realized 30 days after surgery, and 2 new nodules appeared in the superior lip region and close to the surgery site. A new blood count indicated anemia with presence of rouleaux, thrombocytopenia, leucopenia, lymphopenia and monocytopenia, and the biochemical results showed a discrete diminution of aspartate aminotransferase(AST) and a considerable increase on the alkaline phosphatase levels. The cytology of the new nodules indicated plasmacytoma, and was realized a myelogram, that showed dysplastic marrow plasma cells, with more than 20% of plasma cells.Discussion: In the present case, the patient’s lump grew rapidly with bleeding and ulcer formation. The animal presented bone involvement, which characterizes the most suggestive sign of multiple myeloma. Justified by the stimulating factor of osteoclasts, promoting bone lysis, which can cause pathological fractures and pain. The amputation was a partial treatment to attenuates the discomfort and pain presented by the patient. The appearance of new nodules stimulated a more detailed investigation for multiple myeloma. The enzyme AST presented a discrete diminution, and ALT initially was higher than normal, but then returned to normal values. So, the elevated activity of alkaline phosphatase directed the suspects to multiple myeloma, since the activity of AST and ALT was normal, the alkaline phosphatase level was ligated to bone diseases. The rouleaux was constant at the hemograms, this is justified by the excess of immunoglobulins produced in marrow. Based on the chart presented by the patient, the bone marrow was punctured for myelogram. The symptoms displayed by the animal along with the cytological analysis, histopathological, hematological, biochemical and with myelogram indicated diagnosis of multiple myeloma. Other exams could be investigated, for example, detection of Bence Jones proteinuria, serum calcium dosage and inmunoelectroforesis for determination of the type of immunoglobulin produced by the plasma cells in the bone marrow. The definitive diagnostic was established approximately three months after the first consult, emphasizing the importance of a multiple myeloma differential diagnostic in case of plasma cell neoplasm.

Accuracy of Bone Marrow Flow Cytometry Analysis in Patients With Plasma Cell Neoplasm in Thailand: A Single Institutional Study.

Plasma cell neoplasm is a common hematologic malignancy. Treatment with novel agents results in favorable outcomes. Reliable investigations are required to monitor the residual disease, especially after such effective treatments. Flow cytometric analysis is a speedy and accurate method to detect abnormal cells. The aim of this study was to determine diagnostic performance of flow cytometry in the detection of abnormal plasma cells in bone marrow specimens. We included bone marrow samples taken from patients suspected to harbor plasma cell neoplasm at the time of diagnosis or follow-up after treatment from 2013 to 2015. Flow cytometric analyses, using cluster of differentiation (CD)19/CD20/CD27/CD38/CD45/CD56/CD117/CD138 and cytoplasmic κ/λ, were done and results compared with morphologic evaluation of marrow aspirate smear, histology, and immunohistochemistry of marrow biopsy and protein electrophoretic analyses. A total of 154 specimens were included. Plasma cell neoplasm was detected in 56 samples (36.4%). Most abnormal plasma cells in this study were CD19-negative (CD19(-))/CD20(-)/CD27(+)/CD38(+)/CD45(-) (or weakly positive)/CD56(+)/CD117(+)/CD138(+). Light chain restriction was found only in 18 samples (32.1%). Sensitivity and specificity of flow cytometric analysis were 91.1% and 96.9%, respectively. For the follow-up cohort, sensitivity and specificity were 86.7% and 66.7%, respectively. Analysis of plasma cell neoplasm using flow cytometry has high sensitivity and specificity. As an adjunct to marrow histology and immunohistochemistry, flow cytometry can be used in diagnosis of plasma cell neoplasm and more importantly in monitoring the disease after treatment. We propose a limited panel of CD19/CD38/CD45/CD56/CD117/CD138 for detecting minimal residual disease in Thai patients.

Evaluation of the Screening Tests for the Diagnosis of Plasma Cell Neoplasm

Evaluation of the Screening Tests for the Diagnosis of Plasma Cell Neoplasm