Kathryn Foucar

Rapid Presumptive Diagnosis of Hantavirus Cardiopulmonary Syndrome by Peripheral Blood Smear Review

Hantavirus cardiopulmonary syndrome (HCPS) is a rare but frequently lethal acute zoonotic viral infection in rural North America. The rapidity of progression from febrile prodrome to cardiogenic shock and noncardiogenic pulmonary edema requiring intensive care creates high diagnostic urgency and a need for a rapid screening tool. In this retrospective cohort study, 2 pathologists scored blinded peripheral blood smears from 52 patients with HCPS and 128 seronegative patients referred for diagnosis of suspected hantavirus infection. During the prodromal phase, thrombocytopenia was the only consistent abnormality and could be used to indicate hantavirus serologic testing. After the onset of pulmonary edema detected radiographically, the presence of 4 of 5 findings (thrombocytopenia, myelocytosis, hemoconcentration, lack of significant toxic granulation in neutrophils, and more than 10% of lymphocytes with immunoblastic morphologic features) has a sensitivity for HCPS of 96% and a specificity of 99% and missed no patients with HCPS who required intensive care. While each abnormality is commonly seen, the combination of at least 4 of these CBC count data and peripheral blood smear findings can guide early treatment and patient transport decisions until rapid, specific, serologic testing becomes widely available.

Atypical chronic myeloid leukemia is clinically distinct from unclassifiable myelodysplastic/myeloproliferative neoplasms

Atypical chronic myeloid leukemia (aCML) is a rare subtype of myelodysplastic/myeloproliferative neoplasm (MDS/MPN) largely defined morphologically. It is, unclear, however, whether aCML-associated features are distinctive enough to allow its separation from unclassifiable MDS/MPN (MDS/MPN-U). To study these 2 rare entities, 134 patient archives were collected from 7 large medical centers, of which 65 (49%) cases were further classified as aCML and the remaining 69 (51%) as MDS/MPN-U. Distinctively, aCML was associated with many adverse features and an inferior overall survival (12.4 vs 21.8 months, P = .004) and AML-free survival (11.2 vs 18.9 months, P = .003). The aCML defining features of leukocytosis and circulating myeloid precursors, but not dysgranulopoiesis, were independent negative predictors. Other factors, such as lactate dehydrogenase, circulating myeloblasts, platelets, and cytogenetics could further stratify MDS/MPN-U but not aCML patient risks. aCML appeared to have more mutated RAS (7/20 [35%] vs 4/29 [14%]) and less JAK2p.V617F (3/42 [7%] vs 10/52 [19%]), but was not statistically significant. Somatic CSF3R T618I (0/54) and CALR (0/30) mutations were not detected either in aCML or MDS/MPN-U. In conclusion, within MDS/MPN, the World Health Organization 2008 criteria for aCML identify a subgroup of patients with features clearly distinct from MDS/MPN-U. The MDS/MPN-U category is heterogeneous, and patient risk can be further stratified by a number of clinicopathological parameters.

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.

Myelodysplastic/myeloproliferative neoplasms.

Myelodysplastic/myeloproliferative neoplasms (MDS/MPNs) are rare de novo myeloid neoplasms that exhibit hybrid dysplastic and proliferative features at presentation. This SHP/EAHP Workshop session was uniquely problematic owing to the overlap between MDS/MPNs and both chronic myeloproliferative neoplasms and myelodysplasia. The borderline between MDS/MPNs and overt acute myeloid leukemias was also an issue, mainly related to the accurate and consistent delineation of blast equivalents such as promonocytes. Aside from juvenile myelomonocytic leukemia, genetic features defining specific MDS/MPN subtypes have not been identified. Consequently, there is little change in the 2008 World Health Organization classification of MDS/MPNs compared with the 2001 version.

Blastic mantle cell leukemia: an unusual presentation of blastic mantle cell lymphoma.

Six patients had blood and bone marrow manifestations characterized by the presence of morphologically immature or blastic B-lineage lymphoid cells expressing CD5 antigen. The median patient age was 70 years, and the male-to-female ratio was 5:1. The presence or degree of lymphadenopathy and splenomegaly was variable among this group at staging evaluation, although two patients did not have these features. One patient had an antecedent diagnosis of classical nodal mantle cell lymphoma, without prior morphologic blood or bone marrow involvement. Other patients lacked a history of underlying lymphoproliferative disorders. The median white blood cell count was 120 × 109/L. Most patients had thrombocytopenia, whereas only one patient had neutropenia at presentation. Leukemic peripheral blood cells in these six cases were small to medium in size with fine or granular nuclear chromatin and small or inconspicuous nucleoli. The pattern of marrow involvement was interstitial or diffuse, with cells showing immature nuclear features resembling acute leukemia or blastic lymphoma. All tumors demonstrated a consistent immunophenotype of B-cell lineage, surface immunoglobulin positivity, and CD5 antigen expression. The progenitor cell-associated markers CD34 and TdT were not expressed, and CD23 antigen was either negative (three of four cases) or only weakly present (one of four cases). The presence of a karyotypic t(11;14)(q13;q32) was documented in one tumor, whereas two other cases had BCL-1 gene rearrangements by either polymerase chain reaction or Southern blot analysis. Cyclin D1 mRNA overexpression was noted in three of four cases tested. This patient group was characterized by very poor overall survival (median, 3 months; range, 0.5 to 6 months). The aggregate clinical, pathologic, and genetic data in these unusual cases are consistent with de novo or predominant leukemic presentations of blastic mantle cell lymphoma. Accurate diagnosis in such cases is greatly facilitated by cytogenetic studies or the demonstration of BCL-1/cyclin D1 abnormalities.

Mature T-Cell Leukemias Including T-Prolymphocytic Leukemia, Adult T-Cell Leukemia/Lymphoma, and Sézary Syndrome

The 2005 Society for Hematopathology/European Association for Haematopathology Workshop Session 1 was devoted to case presentations with discussions of 3 types of mature T-cell leukemias--T-cell prolymphocytic leukemia, adult T-cell leukemia/lymphoma, and Sézary syndrome. These 3 disorders are clonal proliferations of postthymic alphabeta T cells that are often characterized by systemic manifestations and a leukemic blood picture. The application of clinical, morphologic, immunophenotypic, and genetic studies to the assessment and characterization of these 3 disorders is presented, along with specific diagnostic recommendations and differential diagnostic considerations.

Complex or monosomal karyotype and not blast percentage is associated with poor survival in acute myeloid leukemia and myelodysplastic syndrome patients with inv(3)(q21q26.2)/t(3;3)(q21;q26.2): a Bone Marrow Pathology Group study

Acute myeloid leukemia and myelodysplastic syndrome with inv(3)(q21q26.2)/t(3;3)(q21;q26.2) have a poor prognosis. Indeed, the inv(3)(q21q26.2)/t(3;3)(q21;q26.2) has been recognized as a poor risk karyotype in the revised International Prognostic Scoring System. However, inv(3)(q21q26.2)/t(3;3)(q21;q26.2) is not among the cytogenetic abnormalities pathognomonic for diagnosis of acute myeloid leukemia irrespective of blast percentage in the 2008 WHO classification. This multicenter study evaluated the clinico-pathological features of acute myeloid leukemia/myelodysplastic syndrome patients with inv(3)(q21q26.2)/t(3;3)(q21;q26.2) and applied the revised International Prognostic Scoring System to myelodysplastic syndrome patients with inv(3)(q21q26.2)/t(3;3)(q21;q26.2). A total of 103 inv(3)(q21q26.2)/t(3;3)(q21;q26.2) patients were reviewed and had a median bone marrow blast count of 4% in myelodysplastic syndrome (n=40) and 52% in acute myeloid leukemia (n=63) (P<0.001). Ninety-one percent of patients showed characteristic dysmegakaryopoiesis. There was no difference in overall survival between acute myeloid leukemia and myelodysplastic syndrome patients with inv(3)(q21q26.2)/t(3;3)(q21;q26.2) (12.9 vs. 7.9 months; P=0.16). Eighty-three percent of patients died (median follow up 7.9 months). Complex karyotype, monosomal karyotype and dysgranulopoiesis (but not blast percentage) were independent poor prognostic factors in the entire cohort on multivariable analysis. The revised International Prognostic Scoring System better reflected overall survival of inv(3)(q21q26.2)/t(3;3)(q21;q26.2) than the International Prognostic Scoring System but did not fully reflect the generally dismal prognosis. Our data support consideration of myelodysplastic syndrome with inv(3)(q21q26.2)/t(3;3)(q21;q26.2) as an acute myeloid leukemia with recurrent genetic abnormalities, irrespective of blast percentage.

Diagnosing myelodysplastic/myeloproliferative neoplasms: laboratory testing strategies to exclude other disorders.

Introduction:  The 2008 World Health Organization classification of myeloid neoplasms includes the diagnostic category, myelodysplastic/myeloproliferative neoplasms (MDS/MPN), which encompasses those rare clonal myeloid proliferations that at initial presentation, show overlapping myeloproliferative and myelodysplastic features, making classification as either a myelodysplastic syndrome (MDS) or myeloproliferative neoplasm (MPN) problematic. There are four main subcategories, chronic myelomonocytic leukemia (CMML), atypical chronic myeloid leukemia, BCR‐ABL1‐negative (aCML), juvenile myelomonocytic leukemia (JMML), and myelodysplastic/myeloproliferative neoplasm, unclassifiable (MDS/MPN‐U), which also includes the provisional entity, refractory anemia with ring sideroblasts associated with marked thrombocytosis (RARS‐T). Notably, the morphological features typical of MDS/MPNs are not specific and can be seen in other myeloid neoplasms at presentation or as part of disease progression or transformation.

Bone Marrow Involvement by Hodgkin and Non-Hodgkin Lymphomas

Bone marrow evaluation plays a critical role in staging and predicting prognosis in patients with Hodgkin lymphoma or non-Hodgkin lymphoma. Bone marrow can be the initial site of detection of lymphoma in patients with unexplained symptoms or cytopenias. A comprehensive evaluation of bone marrow includes complete blood counts, blood morphology, bone marrow aspirate, and generous core biopsy sections. Specialized testing should be used in a logical fashion on a case by case basis.

Epstein-barr virus-associated intravascular large t-cell lymphoma presenting as acute renal failure in a patient with acquired immune deficiency syndrome

Intravascular lymphoma (IVL) is a rare neoplasm, recently included as a specific entity in the World Health Organization classification of lymphoid tumors. Most cases are of B-cell lineage; however, rare cases of T-cell phenotype have been reported. We report a human immunodeficiency virus (HIV)-positive patient who died of acute renal failure in whom IVL was identified at autopsy, predominantly involving the renal interstitial vessels. Immunohistochemical stains revealed a T-cell phenotype, which was confirmed by T-cell receptor gamma gene rearrangement studies. The lymphoma cells showed nuclear Epstein-Barr virus (EBV)-encoded RNA transcripts by in situ hybridization, suggesting that EBV might be of etiologic importance in this tumor. The predominant involvement of kidney is unusual. With effective therapy, morbidity and mortality of HIV-1 infection has been substantially reduced, and survival times have been prolonged. However, the relative risk of secondary neoplasms, especially non-Hodgkins lymphoma (NHL), has increased. Consequently, we conclude that unique types of NHL, such as this case of IVL, may be encountered more frequently in this patient population, and that NHL should be added to the list of differential diagnostic considerations in HIV-1-positive patients who develop acute renal failure.