David R. Czuchlewski

Clinicopathologic Features of Agranulocytosis in the Setting of Levamisole-Tainted Cocaine

Levamisole is a known contaminant of cocaine and, via this route, has been associated with otherwise unexplained agranulocytosis. Levamisole is currently present in the majority of cocaine samples seized by the US Drug Enforcement Agency. We identified 20 cases of unexplained agranulocytosis in our practice locations of Albuquerque, NM, and Vancouver, Canada. Epidemiologic investigation revealed recent or ongoing cocaine use in 14 cases (70%). Certain morphologic features, including circulating plasmacytoid lymphocytes, increased bone marrow plasma cells, and mild megakaryocytic hyperplasia, were associated with the cocaine-exposed group. Of 5 patients tested, 3 (60%) were HLA-B27+ and showed antineutrophil antibodies, consistent with known associations of levamisole-induced agranulocytosis. One patient, who was positive for cocaine and levamisole by toxicology testing, died of infectious complications. Inadvertent consumption of levamisole via cocaine is a severely under-appreciated risk factor for agranulocytosis, and specific laboratory features are suggestive of this etiology.

Concomitant BCR-ABL1 translocation and JAK2V617F mutation in three patients with myeloproliferative neoplasms

Chronic myeloproliferative neoplasms (MPN) are clonal disorders of hematopoietic stem cells, which fall into distinct categories based on a number of characteristics including the presence of the BCR-ABL1 gene fusion (chronic myelogenous leukemia) or the JAK2V617F mutation (polycythemia vera, primary myelofibrosis, and essential thrombocythemia). One of the criteria in the 2008 World Health Organization Classification divides MPN into different categories based on the presence of an underlying genetic abnormality, however the WHO does not currently address the classification of myeloproliferative neoplasms that have more than one genetic abnormality. The coexistence of a JAK2V617F mutation and BCR-ABL1 is rare, and to our knowledge, less than 25 cases have been reported in the literature. Our case series examines the clinical, histopathologic, and genetic features of 3 patients with myeloproliferative neoplasms characterized by concomitant BCR-ABL1 and JAK2V617F. The implications for diagnosis and treatment of patients with concomitant BCR-ABL1 and JAK2V617F are discussed as well as how the BCR-ABL1 and JAK2V617F-positive clones may be related to one another.

Scoring of MYC protein expression in diffuse large B-cell lymphomas: concordance rate among hematopathologists.

Recent studies have shown that immunohistochemical evaluation of MYC protein expression in diffuse large B-cell lymphoma is a useful prognostic tool with high concordance rate among pathologists. Concordance in these studies was assessed among few pathologists from one institution by scoring tissue microarrays. In daily practice, MYC evaluation is performed on entire tumor sections by a diverse group of pathologists. In our study, nine hematopathologists from two institutions scored whole-tissue sections of two sets of cases. The training set included 13 cases of diffuse large B-cell lymphoma and 4 cases of Burkitt lymphoma. The validation set included 18 cases of diffuse large B-cell lymphoma and 1 case of Burkitt lymphoma. MYC positivity was defined as ≥40% of tumor cells demonstrating nuclear staining similar to prior studies. The mean score for each case was used to determine MYC status with discrepant cases defined as having any score causing a different MYC status designation. Discrepant cases from the training set were characterized by staining heterogeneity, extensive necrosis or crush artifact and had mean scores within 15 percentage points of 40%. Cases from the validation set that demonstrated any of these features were scored twice on two different days. Overall concordance was moderate (Kappa score: 0.68, P-value<0.001) with no significant change between the two sets (Kappa scores: 0.69 vs 0.67). Thirty-nine percent of cases were discrepant. The findings indicate that a significant number of diffuse large B-cell lymphomas are inherently difficult to score due to staining heterogeneity. The effect of heterogeneity can be under-represented when concordance is measured among few pathologists scoring tissue microarrays. Careful scoring strategy in our study failed to improve concordance. In the absence of specific instructions on how to deal with heterogeneity, caution is advised when evaluating MYC expression in diffuse large B-cell lymphoma.

Congenital erythropoietic porphyria linked to GATA1-R216W mutation: challenges for diagnosis.

Congenital erythropoietic porphyria (CEP) is a rare genetic disease that is characterized by a severe cutaneous photosensitivity causing unrecoverable deformities, chronic hemolytic anemia requiring blood transfusion program, and by fatal systemic complications. A correct and early diagnosis is required to develop a management plan that is appropriate to the patients needs. Recently only one case of X‐linked CEP had been reported, describing the trans‐acting GATA1‐R216W mutation. Here, we have characterized two novel X‐linked CEP patients, both with misleading hematological phenotypes that include dyserythropoietic anemia, thrombocytopenia, and hereditary persistence of fetal hemoglobin. We compare the previously reported case to ours and propose a diagnostic paradigm for this variant of CEP. Finally, a correlation between phenotype variability and the presence of modifier mutations in loci related to disease‐causing gene is described.

Significance of MYD88 L265P Mutation Status in the Subclassification of Low-Grade B-Cell Lymphoma/Leukemia

CONTEXT Lymphoplasmacytic lymphoma (LPL), marginal zone lymphoma (MZL), and chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL) are well-defined clinicopathologic entities. However, distinguishing LPL from MZL and from atypical cases of CLL can sometimes be difficult because of overlapping features. Recent studies have identified a recurrent L265P mutation in the MYD88 gene in most cases of LPL. Although this represents a promising diagnostic marker for LPL, the mutation is also reported in rare cases of MZL and CLL (as well as other types of B-cell lymphoma). Detection rates for this mutation have varied depending on the analytic methodology. OBJECTIVE To assess the diagnostic utility of MYD88 L265P mutation in diagnosing low-grade B-cell lymphomas. DESIGN We developed a novel pyrosequencing assay for the MYD88 L265P mutation and assessed its diagnostic utility in 317 cases of low-grade B-cell lymphoma (45 LPL [14%], 53 MZL [17%], and 219 CLL [69%]). We incorporated formal clinical and pathologic review of selected cases to ensure the most accurate diagnosis and subclassification. RESULTS The MYD88 L265P mutation was identified in 43 cases of LPL (96%), including 3 nonimmunoglobulin-M LPL cases. In contrast, the mutation was present in only 2 cases of MZL (4%), and 5 cases of CLL (2%). Thus, pyrosequencing for the MYD88 L265P mutation demonstrates a high clinical sensitivity and specificity to distinguish LPL from MZL and CLL. CONCLUSIONS This study confirms the strong association of the MYD88 L265P mutation with LPL, as well as the existence of rare cases of small B-cell lymphoma that complicate this association.

Quantitative Image Analysis in the Assessment of Diffuse Large B-cell Lymphoma

Proliferation rates in diffuse large B-cell lymphoma have been associated with conflicting outcomes in the literature, more often with high proliferation associated with poor prognosis. In most studies, the proliferation rate was estimated by a pathologist using an immunohistochemical stain for the monoclonal antibody Ki-67. We hypothesized that a quantitative image analysis algorithm would give a more accurate estimate of the proliferation rate, leading to better associations with survival. In all, 84 cases of diffuse large B-cell lymphoma were selected according to the World Health Organization criteria. Ki-67 percentage positivity estimated by the pathologist was recorded from the original report. The same slides were then scanned using an Aperio ImageScope, and Ki-67 percentage positivity was calculated using a computer-based quantitative immunohistochemistry nuclear algorithm. In addition, chart review was performed and survival time was recorded. The Ki-67 percentage estimated by the pathologist from the original report versus quantitative image analysis was significantly correlated (P<0.001), but pathologist Ki-67 percentages were significantly higher than quantitative image analysis (P=0.021). There was less agreement at lower Ki-67 percentages. Comparison of Ki-67 percentage positivity versus survival did not show significant association either with pathologist estimate or quantitative image analysis. However, although not significant, there was a trend of worse survival at higher proliferation rates detected by the pathologist but not by quantitative image analysis. Interestingly, our data suggest that the Ki-67 percentage positivity as assessed by the pathologist may be more closely associated with survival outcome than that identified by quantitative image analysis. This may indicate that pathologists are better at selecting appropriate areas of the slide. More cases are needed to assess whether this finding would be statistically significant. Due to the good correlation between pathologist estimate and quantitative image analysis, there is no substantial benefit to using quantitative image analysis at this point of time.

Integration of ruxolitinib into dose-intensified therapy targeted against a novel JAK2 F694L mutation in B-precursor acute lymphoblastic leukemia.

A 17‐year‐old girl with B‐cell precursor acute lymphoblastic leukemia (BCP‐ALL) with persistent minimal residual disease (MRD) who underwent standard chemotherapy was found to have a BCR‐ABL1‐like gene expression pattern. Genome sequencing revealed a JAK2 mutation not previously described in BCP‐ALL and a potential therapeutic target. Due to concern for an on‐therapy relapse, the JAK2 inhibitor ruxolitinib was incorporated into a modified chemotherapy backbone to achieve complete remission prior to stem cell transplant. Treatment was well tolerated and she had undetectable MRD prior to a matched allogeneic stem cell transplant and remained in remission at day +100.

PDGFRB-rearranged T-lymphoblastic leukemia/lymphoma occurring with myeloid neoplasms: the missing link supporting a stem cell origin

The 2008 WHO classification scheme of hematolymphoid neoplasms recognizes a category of myeloid and lymphoid neoplasms (MLNs) with eosinophilia and abnormalities of PDGFRA , PDGFRB , or FGFR1 .[1][1] The postulated cell of origin for PDGFRA or FGFR1 -rearranged diseases is a pluripotent progenitor

Diffuse large B-cell lymphoma with florid hemophagocytosis

A 66-year-old woman presented with progressive anemia and, over the course of several months, supervening pancytopenia. The peripheral smear showed marked anisopoikilocytosis with rare spherocytes and schistocytes. A direct antiglobulin test was positive. A bone marrow biopsy showed only mild megakaryocytic hyperplasia; the karyotype was normal. CT scan revealed marked splenomegaly (20 cm) with multiple masses measuring up to 4.7 cm in greatest dimension.

Successful Triage of Suspected Hantavirus Cardiopulmonary Syndrome by Peripheral Blood Smear Review

OBJECTIVES In 2001, the University of New Mexico Hospitals implemented a rapid screening tool for the triage of suspected hantavirus cardiopulmonary syndrome based on peripheral blood smear morphology. Five criteria guided clinical decisions: thrombocytopenia, hemoconcentration, granulocytic left shift, absence of toxic changes, and more than 10% immunoblasts. Smears meeting four of five criteria were previously shown to have high predictive value for infection. Our retrospective study aimed to determine clinical performance of this test over the past decade. METHODS Computerized records of 188 smear results were compared with serology. RESULTS Receiver operator characteristic curve analysis confirmed that the four of five cutoff was the most clinically useful, with sensitivity and specificity of 89% and 93%, respectively. All patients meeting five of five criteria had confirmed infections. Fifteen discordant results were uncovered, explained by positive subsequent tests in the same patient or severe disease without further testing. CONCLUSIONS Our findings confirm that peripheral smear analysis is clinically useful in this endemic region.