Leukemic transformation of primary myelofibrosis: immunophenotype, genotype and growth characteristics of blast cells

Myeloid blastic transformation of myeloproliferative neoplasms--a review of 112 cases

Blastic transformation of myeloproliferative neoplasms (MPN) is still poorly understood. We describe a cohort of 23 Roswell Park Cancer Institute (RPCI) patients and 89 additional cases from the English literature for whom biologic features were described. We initially compared our 23 patients to the 89 cases from the literature. Our population had significantly less patients with prior history of polycythemia vera (PV), shorter time from MPN diagnosis to blastic transformation, <3 prior therapies, more frequent use of hydroxyurea and erythropoietin and less frequent use of alkylating agents. Interestingly, the overall survival of the two cohorts from the time of blastic transformation was similar. We therefore looked at the outcome of the entire cohort (n=112). Patients with prior history of essential thrombocythemia survived longer than patients with prior history of myelofibrosis or PV. Further, patients with <3 prior therapies, those who lacked complex karyotype and those <60 year old at MPN diagnosis had significantly longer survival. Among the PRCI population, 20/23 patients underwent induction treatment with cytarabine and an anthracycline containing regimens; 12 achieved remission and their overall survival was significantly longer than those who did not. Three patients underwent an allogeneic transplantation and their survival was significantly longer than those who did not. Patients with <3 prior therapies, those who lack complex karyotype and those <60 at MPN diagnosis have longer survival following blastic transformation. Finally, allogeneic transplantation represents the only chance for long-term survival in these patients.

Chronic idiopathic myelofibrosis terminating in extramedullary anaplastic plasmacytoma

Chronic idiopathic myelofibrosis (CIMF) is a chronic myeloproliferative disorder (CMPD) with progressive fibrosis and extramedullary hematopoiesis. Similar to other CMPDs, the stem cell in CIMF has the potential to differentiate into myeloid or lymphoid lineages, and thus CIMF can culminate in acute leukemia of myeloid or, rarely, lymphoid lineage. We describe an unusual case of CIMF terminating in extramedullary anaplastic plasmacytoma. The patient was a 61-year-old male with an 11-year history of CIMF. His course was complicated by rapidly growing abdominal and inguinal lymphadenopathy. Lymph node biopsy revealed a diffuse undifferentiated infiltrate in the background of extramedullary hematopoiesis. Flow cytometric and immunohistochemical analysis demonstrated plasma cell-related antigens (CD138, CD38, cytoplasmic kappa light chain), epithelial membrane antigen and CD43 in the tumor cells. The myeloid, B-cell or T-cell markers were negative. A clonal immunoglobulin heavy chain gene rearrangement was identified by polymerase chain reaction. The plasma cell origin was further confirmed by electron microscopic examination, which revealed stacks of rough endoplasmic reticulum. Monoclonal gammopathy may occur in CIMF, and rare cases of simultaneous plasma cell myeloma and CIMF have been reported in the literature. However, to the best of our knowledge, this is the first report of CIMF terminating in extramedullary anaplastic plasmacytoma.

Thrombocytopenia in myelodysplastic syndromes and myelofibrosis

Myelodysplastic syndromes (MDS) are a group of hematopoietic stem cell disorders characterized by ineffective hematopoeisis and an increased risk of transforming to acute myelogenous leukemia (AML). Determining the molecular basis of the disease has been hampered by its heterogeneity. Thrombocytopenia is often a manifestation of MDS and needs to be monitored and treated accordingly. Treating the underlying disorder with a variety of differentiation and immunosuppressive agents alleviates the problem in a small percentage of patients but more often complicates the issue. Several treatments used for primary immune thrombocytopenic purpura (ITP) have been tried in MDS patients, though with only modest success rates. Preliminary studies suggest that the use of a thrombopoietic growth factor may afford substantial increases in platelet levels without excessive deleterious side effects. Primary myelofibrosis (MF) is a chronic myeloproliferative disorder associated with hepatosplenomegaly and refractory cytopenias. Immunomodulatory agents have shown promise in treating the anemia associated with this MF. However, there are currently no standard therapies to treat the thrombocytopenia that is often found in patients with this disease.

Bone Marrow Histopathology in Myeloproliferative Disorders—Current Diagnostic Approach

Current diagnostic issues in chronic myeloproliferative disorders (MPDs) include the differentiation of essential thrombocythemia (ET) from its mimics: early (prefibrotic) stages of chronic idiopathic myelofibrosis (CIMF) and early polycythemia vera (PV), both of which can be associated with thrombocytosis. Applying a systematic evaluation of bone marrow histopathology, in accordance with the current World Health Organization (WHO) classification system, it is possible to identify cases of true ET as opposed to false ET, usually early-stage CIMF accompanied by an excess of platelets. This distinction is important because the frequency of complications such as progression to overt myelofibrosis, blastic crisis, and overall prognosis are significantly different in the two conditions. The diagnostic criteria of the Polycythemia Vera Study Group (PVSG) do not adequately define the initial stages of PV, nor do they distinguish PV with thrombocytosis from ET. Differentiation of the two is possible by bone marrow histopathology, which also is highly predictive (96%) in distinguishing PV from secondary polycythemia. In conclusion, bone marrow biopsy is an important diagnostic tool for distinguishing specific subtypes of MPD and should be a mandatory step for entry evaluation and follow-up of patients enrolled in prospective studies and/or clinical trials.

Primary Myelofibrosis Terminated in Basophilic Leukemia and Successful Allogeneic Bone Marrow Transplantation

Transformation of primary myelofibrosis (PMF) to basophilic leukemia is very rare. We report the case of a 44-year-old man who had had PMF for 6 years. His hematopoiesis deteriorated with marked splenomegaly, requiring multiple red blood cell and platelet transfusions. Soon after splenectomy, progressive basophilia (32.3 x 10(9)/L) developed, infiltrating the skin as well as the bone marrow. The patient underwent allogeneic bone marrow transplantation with cells from an HLA-matched sibling. Despite the presence of hyperhistaminemia (99.1 ng/mL) after conditioning with cyclophosphamide, the pregrafting and post-grafting periods were uneventful. Prophylactic administration of both H1 and H2 receptor antagonists and sufficient hydration appeared to be important.

Myelofibrosis with myeloid metaplasia

MMM is a chronic myeloproliferative disorder characterized by bone marrow fibrosis and neoangiogenesis, constitutive release ofa high number of CD34+ stem cells from the bone marrow, and extramedullary hematopoiesis. It presents with heterogeneous clinical features in which anemia and progression to symptomatic splenomegaly dominate. The pathogenesis is undefined, but the dual action of deregulation of the bFGF pathway may influence myeloproliferation, myelofibrosis, and neoangiogenesis. Animal models suggest that chronic exposure to high doses of thrombopoietin or impairment of the capacity of megakaryocytes to differentiate into platelets, as occurs in the GATA-1(low) mice, is a necessary event for myelofibrosis. Allogeneic stem cell transplantation offers a chance of cure, and low conditioning regimens may extend the age of transplantable patients with lower mortality. Autologus stem cell transplantation and splenectomy are risky procedures that may be considered in patients with advanced disease when conventional therapies for correcting anemia (danazol, recombinant human erythropoietin, or cyclosporine) or chemotherapy for splenomegaly and myeloproliferation (hydroxyurea or interferon alfa) have failed. Thalidomide has been tested in numerous series, and its capacity to improve anemia and thrombocytopenia while reducing splenomegaly has been documented.

Trisomy 13 is associated with poor prognosis in idiopathic myelofibrosis with myeloid metaplasia

We report a case of idiopathic myelofibrosis with trisomy 13 as the sole clonal aberration, as demonstrated by metaphase cytogenetics. The clinical course was especially poor in this case, with death in blast crisis occurring within two weeks from diagnosis. The dismal outcome bears striking similarity to two previous cases of idiopathic myelofibrosis and trisomy 13 reported in the literature. Therefore trisomy 13 may be a predictor of a rapidly fatal outcome in this otherwise indolent disease. Fluorescence in situ hybridisation (FISH) with a chromosome 13 specific probe may enhance the detection of this aberration, since only 50% of cases of idiopathic myelofibrosis are karyotyped successfully using conventional techniques.

Myelofibrosis with myeloid metaplasia: diagnostic definition and prognostic classification for clinical studies and treatment guidelines

PURPOSE

Myelofibrosis with myeloid metaplasia (MMM) is a chronic myeloproliferative disorder characterized by bone marrow fibrosis and extramedullary hematopoiesis. Recent studies provide definite diagnostic criteria and prognostic classifications of the disease, and allogeneic stem-cell transplantation (SCT) now offers a chance of curing the disease. In order to put diagnostic criteria and prognostic classifications of the disease into the perspective of developing guidelines for treatment strategies, all studies published in the English literature over the last 30 years were reviewed.

MATERIALS AND METHODS

Studies were identified through a MEDLINE search (1966 to present) and from the bibliographies of relevant articles.

RESULTS

The Italian Consensus Conference on diagnostic criteria is a structured enterprise aimed at formulating a definition of MMM that will be used for enrolling patients onto clinical studies. It relies on the obligatory presence of myelofibrosis and on the exclusion of the BCR-ABL rearrangement or Philadelphia chromosome, in association with combinations of traditional features. Prognostic scores allow us to identify classes of patients on the basis of hemoglobin, age, WBC count, and chromosomal abnormalities. Several nonrandomized studies have indicated that allogeneic SCT for patients under the age of 55 is effective in prolonging survival in more than 50% of cases and in possibly curing the disease. Patients with the most severe prognosis are candidates.

CONCLUSION

"Consensus" methodology offers a definition of MMM useful for conducting and reporting clinical studies. A detailed knowledge of prognostic factors can help to delineate guidelines for addressing patients with allogeneic SCT.