Clonal Hematopoiesis, Inflammation, and Hematologic Malignancy

Somatic or acquired mutations are postzygotic genetic variations that can occur within any tissue. These mutations accumulate during aging and have classically been linked to malignant processes. Tremendous advancements over the past years have led to a deeper understanding of the role of somatic mutations in benign and malignant age-related diseases. Here, we review the somatic mutations that accumulate in the blood and their connection to disease states, with a particular focus on inflammatory diseases and myelodysplastic syndrome. We include a definition of clonal hematopoiesis (CH) and an overview of the origins and implications of these mutations. In addition, we emphasize somatic disorders with overlapping inflammation and hematologic disease beyond CH, including paroxysmal nocturnal hemoglobinuria and aplastic anemia, focusing on VEXAS (vacuoles, E1 enzyme, X-linked, autoinflammatory, somatic) syndrome. Finally, we provide a practical view of the implications of somatic mutations in clinical hematology, pathology, and beyond.

Superior detection rate of plasma cell FISH using FACS-FISH

OBJECTIVES

Fluorescence in situ hybridization (FISH) for plasma cell neoplasms (PCNs) requires plasma cell (PC) identification or purification strategies to optimize results. We compared the efficacy of cytoplasmic immunoglobulin FISH (cIg-FISH) and fluorescence-activated cell sorting FISH (FACS-FISH) in a clinical laboratory setting.

METHODS

The FISH analysis results of 14,855 samples from individuals with a suspected PCN subjected to cytogenetic evaluation between 2019 and 2022 with cIg-FISH (n = 6917) or FACS-FISH (n = 7938) testing were analyzed.

RESULTS

Fluorescence-activated cell sorting-FISH increased the detection rate of abnormalities in comparison with cIg-FISH, with abnormal results documented in 54% vs 50% of cases, respectively (P < .001). It improved the detection of IGH::CCND1 (P < .001), IGH::MAF (P < .001), IGH::MAFB (P < .001), other IGH rearrangements (P < .001), and gains/amplifications of 1q (P < .001), whereas the detection rates of IGH::FGFR3 fusions (P = .3), loss of 17p (P = .3), and other abnormalities, including hyperdiploidy (P = .5), were similar. Insufficient PC yield for FISH analysis was decreased between cIg-FISH and FACS-FISH (22% and 3% respectively, P < .001). Flow cytometry allowed establishment of ploidy status in 91% of cases. In addition, FACS-FISH decreased analysis times, workload efforts, and operating costs.

CONCLUSIONS

Fluorescence-activated cell sorting-FISH is an efficient PC purification strategy that affords significant improvement in diagnostic yield and decreases workflow requirements in comparison with cIg-FISH.

Low cholesterol levels are associated with increasing risk of plasma cell neoplasm: A UK biobank cohort study

BACKGROUND

Plasma cell neoplasms are a group of hematologic neoplasms that often develop in the elderly population. The relationship between cholesterol levels and hematologic malignancy has been identified in population studies. However, it is still unclear if there is a relationship between cholesterol levels and plasma cell neoplasm in European ancestry.

METHODS

Prospective cohorts included 502,507 individuals from the UK Biobank who were followed up to 2019 and assessed total cholesterol(TC) levels, low-density lipoprotein (LDL) levels, high-density lipoprotein (HDL) levels, apolipoprotein A (ApoA) and apolipoprotein B (ApoB) as risk factors for plasma cell neoplasms with Cox proportional hazard regression and restricted cubic spline model. We also used two-sample Mendelian randomization to determine if the cholesterol level has a causal effect on developing plasma cell neoplasms.

RESULTS

We observed 1819 plasma cell neoplasm cases during 14.2 years of follow-up in the UK Biobank. We found higher blood serum cholesterol levels at baseline were associated with a lower risk of plasma cell neoplasm in our study. All lipid profiles we analyzed in this study were inversely associated with plasma cell neoplasm risk (all ptrend  <0.005) but triglycerides did not have such association. However, there was no suggestive association of genetically predicted serum LDL, HDL, and total cholesterol levels with multiple myeloma.

CONCLUSION

Low serum total cholesterol, LDL, HDL, ApoA, and ApoB levels were all associated with increasing the risk of plasma cell neoplasm.

Association between Prostate Carcinoma and Multiple Myeloma

Synchronous or sequential development of multiple myeloma and prostate carcinoma is rare. It is not sure whether these two occur independently or if one influences the development of the other. We reviewed the cases published in the English literature; eight cases of myeloma developing after diagnosis and treatment for prostate carcinoma, five cases of simultaneous occurrence of myeloma and prostate carcinoma, and five cases where the patient with multiple myeloma later developed prostate carcinoma were found. This short review attempts to analyze the occurrence of these two diseases in the same patient and dissect whether there is a close association or it is just a mere coincidence.

Nutritional Status Indices and Monoclonal Gammopathy of Undetermined Significance Risk in the Elderly Population: Findings from the National Health and Nutrition Examination Survey

OBJECTIVE

Although several studies have found dietary intake is related to multiple myeloma (MM) and its precursor status risks, the role of one's nutritional status has been ignored and its role in plasma cell neoplasm development is still unclear. This study aimed to explore the relationship between various clinical indices of nutritional status and the risk of monoclonal gammopathy of undetermined significance (MGUS) in the population.

METHODS

We selected 9520 participants from the NHANES III and NHANES 1999-2004 studies. Controlling nutritional status index (CONUT), prognostic nutritional index (PNI), geriatric nutritional risk index (GNRI) and body mass index (BMI) were calculated as indices of nutritional status of the participants. Associations between nutritional indices and MGUS were investigated using multiple logistic regression, subgroup analysis, and an RCS model.

RESULTS

In our study, 266 participants had MGUS, with a prevalence of 2.79%. This study found that CONUT and PNI identified populations with poor nutritional status and had a significant positive correlation with the risk of MGUS. In multivariate logistic regression, compared with the lower CONUT score (<3) group, the OR for the group with higher scores (≥3) was 1.805 (95%CI: 1.271, 2.564). Compared with the lowest quartile group, the highest quartile PNI score group had an OR of 0.509 (95%CI: 0.290, 0.896). GNRI had no significant correlation with the risk of MGUS, with an OR of 0.737 (95%CI: 0.443, 1.227).

CONCLUSION

This study found that older adults with CONUT and PNI scores indicating poorer nutrition had a higher risk of MGUS.

Squash Cytology Diagnosing Plasmacytoma of Frontal Bone as First Presentation of Nonsecretory Multiple Myeloma

Plasmacytoma of bone is one of the criteria for diagnosing plasma cell myeloma (multiple myeloma). A plasmacytoma involving a frontal bone is unusual, with only few being reported so far. Also, when typical clinical presentation is absent, diagnosis is usually not suspected clinicoradiologically. We report a rare case of frontal bone plasmacytoma presenting as a lump over the forehead, the squash cytology of which gave the diagnosis of neoplastic etiology. Thus, squash cytology helped in early and definitive diagnosis in this patient, hastening meticulous diagnostic investigations and appropriate management. With full workup, the final diagnosis of a nonsecretory multiple myeloma was made.

POEMS syndrome: A rare entity

POEMS syndrome is a rare paraneoplastic syndrome due to an underlying plasma cell disorder. The diagnosis of POEMS syndrome can be a challenge. A good history, physical examination, and appropriate testing can aid in establishing its diagnosis. We are presenting the case of a 75-year-old man who was diagnosed with POEMS syndrome.

A Rare Case of Primary Duodenal Plasmacytoma: An Incidental Finding

Solitary extramedullary plasmacytoma (SEP) is a rare tumor due to the monoclonal proliferation of plasma cells without bone marrow involvement. Plasmacytomas are frequently encountered in bone or soft tissue but rarely occur in the gastrointestinal (GI) tract. They can present with a multitude of symptoms depending on their site. This report describes a case of SEP diagnosed as a duodenal ulcer (DU) during esophagogastroduodenoscopy (EGD) for iron deficiency anemia.

Clinico-pathological profile of patients with plasma cell neoplasms with special reference to bone marrow fibrosis and amyloid deposition

To clarify the significance of bone marrow fibrosis and amyloid deposition in plasma cell neoplasm, a retrospective cross-sectional study for a period of 3 years was conducted. Patients who underwent bone marrow aspiration and biopsy with suspicion of plasma cell neoplasms were included in the study. The bone marrow findings were correlated with clinical profile of the patient along with biochemical parameters, cytogenetics, Fluorescent in situ hybridization (FISH) wherever available. A total of 273 bone marrow aspirates and biopsies of patients with suspected plasma cell neoplasms were analyzed. There were 181 male patients and 92 female patients (Male: Female = 1.96: 1). There were 245 cases of multiple myeloma (89.7%), 8 cases of primary amyloidosis (2.9%) and 6 monoclonal gammopathy of undetermined significance (MGUS) (2.1%), 5 cases of plasmacytoma (1.8%) and 4 cases of smouldering myeloma (1.4%), 5 cases of POEMS syndrome (1.8%). Bone marrow fibrosis was noted in 12 patients at diagnosis (4.3%). Among the parameters studied, only the mean Hemoglobin was significantly low in patients with marrow fibrosis. Amyloid deposition in various organs including bone marrow, kidney, liver etc., were noted in 17 patients overall (6.2%). In conclusion, the incidence of fibrosis (4.3%) and amyloidosis (6.2%) associated with plasma cell neoplasms were much lower in our study as compared to published studies.

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

AIMS

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).

METHODS

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.

RESULTS

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.

CONCLUSION

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.

Analysis of the Treatment and Survival of Sinonasal Extramedullary Plasmacytoma

BACKGROUND

While extramedullary plasmacytomas are infrequently encountered plasma cell malignancies, most cases occur in the head and neck, with a predilection for the sinonasal cavity. Due to the rarity of this disease, the majority of studies on sinonasal extramedullary plasmacytoma (SN-EMP) are case reports or small retrospective case series.

OBJECTIVE

To investigate the impact of patient, disease, and treatment factors on the survival of patients with SN-EMP.

METHODS

The National Cancer Database was queried for all patients with SN-EMP between 2004-2016 (N = 381 cases). Univariate and multivariate analyses were used to examine patient demographics, tumor characteristics, and survival.

RESULTS

The majority of SN-EMP patients were over 60 years old (57.0%), male (69.8%), and white (86.2%). The most common treatment modality was radiotherapy alone (38.6%), followed by surgery plus radiotherapy (37.8%). Five-year overall survival was 74.0% and median survival was 9.1 years. Accounting for patient demographics and tumor characteristics in a multivariate model, the following groups had worse prognosis: 60 and older (HR 1.99, p = 0.031) and frontal sinus primary site (HR 11.56, p = 0.001). Patients who received no treatment (HR 3.89, p = 0.013), chemotherapy alone (HR 5.57, p = 0.008) or radiotherapy plus chemotherapy (HR 2.82, p = 0.005) had significantly lower survival than patients who received radiotherapy alone. Patients who received surgery with radiotherapy (HR 0.57, p = 0.039) had significantly higher survival than patients who received radiotherapy alone.

CONCLUSION

In patients with SN-EMP five-year overall survival was found to be 74.0% with decreased survival associated with a frontal sinus primary site and being aged 60 or older. Patients receiving no treatment, chemotherapy alone, or radiotherapy with chemotherapy was associated with lower survival. Receiving surgery plus radiotherapy was associated with the highest five-year overall survival.

Case report: gastric plasmacytoma resistant to radiation therapy

Plasma cell neoplasms are a group of diseases involving the malignant proliferation of plasma cells. One common type of plasma cell neoplasm is multiple myeloma, which typically occurs diffusely in the bone marrow. It can manifest with a variety of presentations, including bone pain, fractures, anemia, infection, hypercalcemia, and renal failure. A less common type of plasma cell neoplasm is the solitary plasmacytoma, which is a local proliferation of plasma cells in the bone or extramedullary tissues. They rarely recur after local radiation therapy.An 83-year-old woman was noted on routine labwork to have elevated total serum protein, and serum immunofixation confirmed IgG/Kappa paraprotein. There was no evidence of end-organ damage characteristic of myeloma: hypercalcemia, renal dysfunction, anemia, or bone lesions. She was diagnosed with monoclonal gammopathy of undetermined significance and placed on observation. Seven years later, she developed mild anemia and an increasing M spike. No abnormalities were found on bone marrow biopsy apart from mildly increased plasma cell proliferation (7-10% of total cells). A PET scan showed increased gastric uptake, concerning for possible gastric malignancy. Upper gastrointestinal endoscopic ultrasound revealed extrinsic compression of the stomach fundus and body due to a 40 mm mass and associated adenopathy. Pathology revealed a kappa-restricted plasma cell neoplasm positive for CD138.The patient underwent radiation therapy localized to the gastric area. Subsequent evaluation revealed a persistent gastric mass. Attempted biopsy resulted in a gastrointestinal bleed, rendering her unable to undergo treatment with lenalidomide and aspirin. She is currently undergoing chemotherapy with bortezomib, cyclophosphamide, and dexamethasone. The case illustrates the potential diversity of plasma cell dyscrasia clinical manifestations. Gastric plasmacytomas are an uncommon type of extramedullary plasmacytoma, particularly rare when resistant to radiation therapy.

Predictive value of 1q21 gain in multiple myeloma is strongly dependent on concurrent cytogenetic abnormalities and first-line treatment

Improved therapies in multiple myeloma (MM) have forced a constant risk stratification update, first Durie-Salmon, then international scoring systems (ISS), next revised-ISS (RISS) including high-risk cytogenetic abnormalities (HRCAs) such as del(17p) and t(4;14), and now R2-ISS including 1q21 gain has been proposed. Predictive value of 1q21 gain by itself or in concurrence with other cytogenetic abnormalities is evaluated in 737 real-world plasma cell neoplasm (PCN) patients under current therapies. Ten-year progression-free survival (10y-PFS) rates for patients with 2, 3 and >3 copies of 1q21 were 72.2%, 42.5% and 43.4% (P<1.1×10^-17). Cox regression analysis confirmed that 1q21 gain was an independent prognostic factor for PFS (HR=1.804, P<0.0001, Harrell C-statistic =0.7779±0.01495) but not for OS (P=0.131). Gain of 1q21 was strongly associated with hypodiploidy (38.8% vs. 7.0%, P=1.3×10^-22), hyperdiploidy (44.1% vs. 16.4%, P=1.6×10^-13), HRCAs (12.6% vs. 3.5%, 1.8×10^-5), IGH breaks (12.3% vs. 2.1%, P=2.1×10^-7) and del(13q) (8.0% vs. 4.0%, P=0.031). In our series, 1q21 gain by itself did not improve RISS predictive capacity in patients either eligible or ineligible for autologous stem cell transplantation (ASCT). However, compared with patients with other 1q21 gains: concurrence with hyperdiploidy improved the prognosis of ASCT-eligible patients from 62.5% to 96.0% 10-year overall-survival (10y-OS, P<0.002); concurrence with hypodiploidy improved the prognosis of ASCT-ineligible patients from 35.7% to 71.0% (P=0.013); and concurrence with del(13q) worsened the prognosis of ASCT-ineligible patients from 12.5% to 53.4% (P=0.035). Gain of 1q21 should be patient-wisely evaluated, irrespective of the RISS, considering its concurrence with other cytogenetic abnormalities and eligibility for ASCT.

Correlation between peripheral blood automated hematopoietic progenitor cell counts and flow cytometric CD34+ cell counts differs according to diagnosis in patients undergoing autologous peripheral blood stem cell transplantation

BACKGROUND

An automated hematopoietic progenitor cell count measurement in Sysmex XN analyzer (XN-HPC) has been developed to assist flow cytometry CD34⁺ cell count measurement, which requires technical expertise and a long turnaround time. Here, we evaluated the correlation between XN-HPC count and flow cytometric CD34⁺ cell count in pre-harvest peripheral blood (PB) samples from patients undergoing autologous peripheral blood stem cell (PBSC) transplantation according to diagnosis and investigated the possible cause of the decreased correlation in plasma cell neoplasm patients.

MATERIALS AND METHODS

We retrospectively included 399 patient data that had matched PB XN-HPC count and CD34⁺ cell count of PB and apheresis product from Samsung Medical Center (SMC) and the Hematopoietic Stem Cell (HSC) registry. We assessed the diagnostic accuracy and the potential cutoff values of XN-HPC count for predicting adequate PBSC collection.

RESULTS

The PB XN-HPC count was 1.6 and 1.3-fold higher than the CD34⁺ cell count in SMC (25.0 vs 15.9/μl) and the HSC registry (20.0 vs 15.2/μl), respectively. Overall the correlation between the PB XN-HPC and CD34⁺ cell count was moderate (SMC, r = 0.71; HSC registry, r = 0.66). A significant proportional and systemic bias with overestimation of XN-HPC count were noted in the plasma cell neoplasm patients in both SMC and the HSC registry. However, no significant difference in correlation was observed according to myeloma-related laboratory parameters in plasma cell neoplasm patients.

CONCLUSION

Our results suggest that XN-HPC count should be interpreted cautiously in cancer patients undergoing autologous PBSC transplantation, especially in those with plasma cell neoplasm.

Atypical Presentation of Plasma Cell Neoplasm of the Sternum

Multiple myeloma (MM) is a rare plasma cell neoplasm characterized by monoclonal cell infiltration in the bone marrow, which can cause anemia, bone pain, and recurrent infections. Extramedullary myeloma (EM) is a rare clinical presentation with a poor prognosis. It involves the accumulation of clonal plasma cells in soft tissues with a tumor-like appearance, either presenting as a primary (initial) or secondary (relapse) malignancy. We present a case of a 65-year-old male who experienced an abrupt onset of chest pain associated with a localized sternal mass while exercising the day prior to arrival. Chest computed tomography (CT) scan with contrast revealed an expansile lytic lesion around the sternal area. Due to high suspicion for malignancy, a CT-guided core needle biopsy was done, which showed plasma cells with rare Dutcher bodies consistent with MM. Bone marrow smear showed the presence of 70% plasma cells confirming a diagnosis of MM. Early detection of this devastating disease may help improve survival. Therefore, physicians should have a high index of suspicion for MM in older patients with similar clinical presentations.

Proliferation to Apoptosis Tumor Cell Ratio as a Biomarker to Improve Clinical Management of Pre-Malignant and Symptomatic Plasma Cell Neoplasms

Proliferation and apoptosis of neoplastic cells are prognostic biomarkers in plasma cell neoplasms (PCNs). The prognostic capacity of proliferation to apoptosis ratio (Ratio-PA) in the era of immunomodulatory treatments is re-evaluated in 316 gammopathy of undetermined significance (MGUS), 57 smoldering multiple myeloma (SMM), and 266 multiple myeloma (MM) patients. Ratio-PA of 0.77 ± 0.12, 1.94 ± 0.52, and 11.2 ± 0.7 (p < 0.0001) were observed in MGUS, SMM, and MM patients. Ten-year overall survival (10y-OS) rates for patients with low/high Ratio-PA were 93.5%/77.3% p < 0.0001) for MGUS, 82.5%/64.7% (p < 0.05) for SMM, and 62.3%/47.0% (p < 0.05) for MM. For patients with low, intermediate, and high risk, 10y-OS for low/high Ratio-PA were 95.5%/72.9% (p < 0.0001), 74.2%/50.4% (p < 0.0001), and 35.3%/20.0% (p = 0.836), respectively. Ratio-PA was an independent prognostic factor for OS (HR = 2.119, p < 0.0001, Harrell-C-statistic = 0.7440 ± 0.0194) when co-analyzed with sex, age, and standard risk. In patients with Ratio-PA^high, only first-line therapy with VRd/VTd, but not PAD/VCD, coupled with ASCT was associated with high 10y-OS (82.7%). Tumor cell Ratio-PA estimated at diagnosis offers a prognostic biomarker that complements standard risk stratification and helps to guide the clinical management of pre-malignant and symptomatic PCNs. Every effort should be made to provide first-line therapies including VTd or VRd associated with ASCT to patients with Ratio-PA^high at higher risk of progression and death.

Solitary plasmacytoma of jaw bone: A case report and systematic review of fifty cases from literature

Solitary plasmacytoma of bone (SPB) is a localized form of plasma cell neoplasm where jaw involvement is rare. Distinguishing SPB from other plasma cell neoplasms is critical for treatment and survival. Here, a case of SPB of mandible in an elderly female is reported. Histopathological diagnosis of plasma cell neoplasm was confirmed immunohistochemically with MUM1 and CD138 positivity and multiple myeloma (MM) was ruled out on performing systemic workup. Prognosis of SPB worsens when it transforms into MM. A systematic review was undertaken with the objective to determine the factors affecting conversion of SPB to MM. An electronic search was undertaken with PubMed/MEDLINE, Web of Science and Science Direct. Fifty cases of SPB of jaw from 29 publications were reviewed. SPB commonly presents as a painless swelling. Radiographically, it is commonly seen as multilocular radiolucency with well-defined borders. Follow-up data showed that nine cases turned into MM in a mean duration of 1 year 9 months and 12 patients died after median disease-free survival of 6 years 9 months. Prognosis of SPB is found to be affected by tumor size (≥5 cm), anaplasia of tumor cells, Ki-67 labeling index, vascularity of the tumor, presence of clonal bone marrow plasma cells, serum immune globulin level, dose of radiotherapy and persistence of M protein after treatment. There is a need to identify prognostic subgroups in SPB based on these factors. Furthermore, studies are necessary for standardization of treatment protocol to halt or prolong the progression of SPB to MM.

Plasma cell neoplasm with varied morphology: A report of two cases

Plasma cell (PC) neoplasm (PCN) with varied morphology has been described in the literature. The majority of clonal proliferation of PCs is composed of easily recognizable morphology in the bone marrow (BM). However, few cases may cause diagnostic complexity, as they exhibit varied cytological and architectural heterogeneity which may pose problem in morphological diagnosis and require the use of ancillary techniques like immunohistochemistry (IHC). We illustrate here two such cases of PCN with varied morphology in BM aspirate, in the form of clustering/rosetting and multiple clear cytoplasmic vacuoles, respectively, leading to varied differential diagnosis. However, later, the histopathological features on BM biopsy findings were relatively characteristic and IHC confirmed the final diagnosis. The morphological variants documented in both these cases are exceptional and representative of the various forms of atypical PCs.

Thrombocytosis as an Initial Presentation of Plasma Cell Neoplasm: A Case Report

Plasma cell neoplasms are usually associated with normal or decreased platelet count. The association of thrombocytosis and multiple myeloma is exceedingly rare, with only six such cases reported in the literature until now. Differentiating clonal from secondary causes of thrombocytosis can be extremely difficult, yet the distinction has important therapeutic implications. We report the case of a woman presenting with thrombocytosis that led to the diagnosis of multiple myeloma. The possible etiological link between both these entities is also discussed.

Development of an unbiased, semi-automated approach for classifying plasma cell immunophenotype following multicolor flow cytometry of bone marrow aspirates

BACKGROUND

Despite increased usage of multiparameter flow cytometry (MFC) to assess diagnosis, prognosis, and therapeutic efficacy (minimal residual disease, MRD) in plasma cell neoplasms (PCNs), standardization of methodology and data analysis is suboptimal. We investigated the utility of using the mean and median fluorescence intensities (FI) obtained from MFC to objectively describe parameters that distinguish plasma cell (PC) phenotypes.

METHODS

In this retrospective study, flow cytometry results from bone marrow aspirate specimens from 570 patients referred to the Myeloma Institute at UAMS were evaluated. Mean and median FI data were obtained from 8-color MFC of non-neoplastic, malignant, and mixed PC populations using antibodies to CD38, CD138, CD19, CD20, CD27, CD45, CD56, and CD81.

RESULTS

Of 570 cases, 252 cases showed only non-neoplastic PCs, 168 showed only malignant PCs, and 150 showed mixed PC populations. Statistical analysis of median FI data for each CD marker showed no difference in expression intensity on non-neoplastic and malignant PCs, between pure and mixed PC populations. ROC analysis of the median FI of CD expression in non-neoplastic and malignant PCs was used to develop an algorithm to convert quantitative FI values to qualitative assessments including "negative," "positive," "dim," and "heterogeneous" expression.

CONCLUSIONS

FI data derived from 8-color MFC can be used to define marker expression on PCs. Translation of FI data from Infinicyt software to an Excel worksheet streamlines workflow and eliminates transcriptional errors when generating flow reports. © 2018 International Clinical Cytometry Society.

Clonality of neutrophilia associated with plasma cell neoplasms: report of a SETBP1 mutation and analysis of a single institution series

A rare but well-known association between plasma cell neoplasms and neutrophilia is known to exist. Whether the neutrophilia is secondary to the plasma cell neoplasm or this convergence represents two independent clonal disorders is unclear. We reviewed five consecutive cases from a single institution over a 3-year period, applying molecular, cytogenetic and cytokine-profiling approaches to determine whether neutrophilia associated with plasma cell neoplasms represents a reactive or clonal process. We report, for the first time, the occurrence of a SETBP1 mutation in two cases, as well as changes in G-CSF and IL-6 in SETBP1 wild type vs. mutated patients that are supportive of a hypothesis that neutrophilia associated with plasma cell neoplasms may sometimes be reactive and may sometimes represent a second clonal entity. Finally, using an ex vivo drug screening platform we report the potential efficacy of the multi-kinase inhibitor dasatinib in select patients.

Solitary bone plasmacytoma: An interesting case report with unusual clinico-cytological features

Solitary bone plasmacytoma (SBP) is a rare entity characterized by localized proliferation of monoclonal plasma cells primarily occurring in the axial skeleton without systemic involvement. Involvement of the distal extremity is unusual. In the absence of typical clinical presentation, diagnosis may not be suspected clinico-radiologically; hence, fine-needle aspiration cytology may help in early and definitive diagnosis, hastening meticulous diagnostic workup and appropriate management of these patients. Intracytoplasmic crystalline inclusions (CI) have been reported in multiple myeloma and lymphoproliferative disorders. The present case highlights unusual clinico-cytological features of SBP with primary involvement of humerus, progression to tibia, and presence of extracellular and intracytoplasmic CI in plasma cells, a morphologic finding not reported in SBP earlier.