Hendrik De Raeve

Changing concepts of diagnostic criteria of myeloproliferative disorders and the molecular etiology and classification of myeloproliferative neoplasms: From Dameshek 1950 to Vainchenker 2005 and beyond

The Polycythemia Vera Study Group (PVSG) and WHO classifications distinguished the Philadelphia (Ph1) chromosome-positive chronic myeloid leukemia from the Ph1-negative myeloproliferative neoplasms (MPN) essential thrombocythemia (ET), polycythemia vera (PV) and primary myelofibrosis (MF) or primary megakaryocytic granulocytic myeloproliferation (PMGM). Half of PVSG/WHO-defined ET patients show low serum erythropoietin levels and carry the JAK2V617F mutation, indicating prodromal PV. The positive predictive value of a JAK2V617F PCR test is 95% for the diagnosis of PV, and about 50% for ET and MF. The WHO-defined JAK2V617F-positive ET comprises three ET phenotypes at clinical and bone marrow level when the integrated WHO and European Clinical, Molecular and Pathological (ECMP) criteria are applied: normocellular ET (WHO-ET), hypercellular ET due to increased erythropoiesis (prodromal PV) and hypercellular ET associated with megakaryocytic granulocytic myeloproliferation (EMGM). Four main molecular types of clonal MPN can be distinguished: JAK2V617F-positive ET and PV; JAK2 wild-type ET carrying the MPL515; mutations in the calreticulin (CALR) gene in JAK2/MPL wild-type ET and MF, and a small proportion of JAK2/MPL/CALR wild-type ET and MF patients. The JAK2V617F mutation load is low in heterozygous normocellular WHO-ET. The JAK2V617F mutation load in hetero-/homozygous PV and EMGM is clearly related to MPN disease burden in terms of splenomegaly, constitutional symptoms and fibrosis. The JAK2 wild-type ET carrying the MPL515 mutation is featured by clustered small and giant megakaryocytes with hyperlobulated stag-horn-like nuclei, in a normocellular bone marrow (WHO-ET), and lacks features of PV. JAK2/MPL wild-type, CALR mutated hypercellular ET associated with PMGM is featured by dense clustered large immature dysmorphic megakaryocytes and bulky (cloud-like) hyperchromatic nuclei, which are never seen in WHO-ECMP-defined JAK2V617F mutated ET, EMGM and PV, and neither in JAK2 wild-type ET carrying the MPL515 mutation. Two thirds of JAK2/MPL wild-type ET and MF patients carry one of the CALR mutations as the cause of the third distinct MPN entity. WHO-ECMP criteria are recommended to diagnose, classify and stage the broad spectrum of MPN of various molecular etiologies.

Aspirin-Responsive, Migraine-Like Transient Cerebral and Ocular Ischemic Attacks and Erythromelalgia in JAK2V617F-Positive Essential Thrombocythemia and Polycythemia Vera

Migraine-like cerebral transient ischemic attacks (MIAs) and ocular ischemic manifestations were the main presenting features in 10 JAK2V617F-positive patients studied, with essential thrombocythemia (ET) in 6 and polycythemia vera (PV) in 4. Symptoms varied and included cerebral ischemic attacks, mental concentration disturbances followed by throbbing headaches, nausea, vomiting, syncope or even seizures. MIAs were frequently preceded or followed by ocular ischemic events of blurred vision, scotomas, transient flashing of the eyes, and sudden transient partial blindness preceded or followed erythromelalgia in the toes or fingers. The time lapse between the first symptoms of aspirin-responsive MIAs and the diagnosis of ET in 5 patients ranged from 4 to 12 years. At the time of erythromelalgia and MIAs, shortened platelet survival, an increase in the levels of the platelet activation markers β-thromboglobulin and platelet factor 4 and also in urinary thromboxane B2 were clearly indicative of the spontaneous in vivo platelet activation of constitutively JAK2V617F-activated thrombocythemic platelets. Aspirin relieves the peripheral, cerebral and ocular ischemic disturbances by irreversible inhibition of platelet cyclo-oxygenase (COX-1) activity and aggregation ex vivo. Vitamin K antagonist, dipyridamole, ticlopidine, sulfinpyrazone and sodium salicylate have no effect on platelet COX-1 activity and are ineffective in the treatment of thrombocythemia-specific manifestations of erythromelalgia and atypical MIAs. If not treated with aspirin, ET and PV patients are at a high risk of major arterial thrombosis including stroke, myocardial infarction and digital gangrene.

The 2006 2008 European Clinical, Molecular and Patholobiogical (2008 ECMP) Classification and the 2007 WHO Revised Criteria for Myeloproliferative Neoplasms

The classifications of Myeloproliferative Disorders (MPD) by the Polycythemia Vera Study Group (PVSG) and World Health Organization (WHO) used crude criteria for the diagnoses of Essential Thrombocythemia (ET), Polycythemia Vera (PV) and Primary Myelo Fibrosis (PMF). The PVSG and the 2007 WHO criteria for the diagnosis of ET and PVoverlook the very early prefibrotic stages of MPN. The 2008 European Clinical, Molecular and Pathological (2008 ECMP) criteria are sensitive for the detection of early stages of JAK2 V617F trilinear Myelo Proliferative Neoplasms (MPN) and could delineate three stages JAK2 V617F mutated ET: normocellular ET; ET with features of early PV (prodromal PV); and ET with Hypercellular Megakaryocytic Granulocytic Myeloproliferation (EMGM). The 2008 ECMP classification distinguishes six clinical PV stages that have important prognostic and therapeutic implications. Spontaneous EEC, low serum erythropoietin (EPO) levels and JAK2 mutations are highly specific for ET with PV features (prodromal PV), masked PV and classical PV. JAK2 wild type ET and MF have no blood and bone marrow features of PV. The detection and quantitation of JAK2 V617F mutation allele burden play a key-role in the diagnostic work-up and staging of ET, PV and MF patients. The JAK2 V617F mutation allele burden in heterozygous mutated ET and in combined heterozygous-homozygous or homozygous mutated PV and EMGM is of major clinical and prognostic significance. Pre-treatment bone marrow histopathology is of huge importance to document and stage the broad spectrum JAK2 mutated and JAK wild type MPN. JAK2 wild type ET carrying the MPL 515 mutation is a separate and distinct MPN entity of ET and MF without features of PV at diagnosis and during follow-up. JAK2 wild type hypercellular ET associated with Primary Megakaryocytic Granulocytic Myeloproliferation (PMGM) is the third MPN entity of elusive etiology. Myelofibrosis (MF) is not a primary MPN disease entity because Reticulin Fibrosis (RF) and Reticulin/Collagen Fibrosis (RCF) are a secondary response of polyclonal fibroblasts to cytokines released from the clonal granulocytic and megakaryocytic proliferative cells.

2014 WHO Clinical Molecular and Pathological (WHO-CMP) Diagnostic Criteria for the Classification and Staging of Five Distinct JAK2, MPL and CALR Mutated Myeloproliferative Neoplasms

Somatic mutations in the JAK2, MPL and calreticulin (CALR) genes are the driver causes of clonal myeloproliferative neoplasms (MPN). Applying the WHO Clinical, Molecular and Pathologic (WHO-CMP) classification of MPN, the JAK2 V617F positive ET patients comprise three phenotypes of ET: normocellular ET, hypercellular ET due to increased erythropoiesis (prodromal PV) and ET with hypercellular megakaryocytic-granulocytic myeloproliferation (ET.MGM or masked PV). The percentage of JAK2V617F mutation load is low and stable in heterozygous normocellular ET and increasingly high in hetero/homozygous PV and masked PV. The JAK2 V617F allele burden is related to MPN disease burden in terms of splenomegaly, constitutional symptoms and myelofibrosis. Five distinct clonal MPNs can be distinguished: JAK2 V617F mutated ET and PV; JAK2 exon 12 PV and the JAK2 wild type ET and MF caused by the somatic mutations MPL 515 or CALR. JAK2 mutated trilinear MPN reflects a broad spectrum of ET, prodromal or masked PV and classical PV, but the JAK2 wild type MPL or CALR positive ET and MF lack features of PV at diagnosis and during follow-up. Bone marrow features in JAK2 V617F mutated ET and PV are similar and featured by medium sized to large (pleomorphic) megakaryocytes with only a few giant forms. Bone marrow histology in MPL515 mutated ET and MF is featured by clustered small and giant megakaryocytes with hyperlobulated stag-horn-like nuclei, in a normocellular bone marrow with no features of PV. Bone marrow histology in CALR mutated ET and MF is featured by dense clustered large immature dysmorphic megakaryocytes and bulky (cloude-like) hyperchromatic nuclei similar as described in primary megakaryocytic granylocytic myeloproliferation (PMGM), which are never seen in JAK2

Autosomal Dominant Hereditary Essential Thrombocythemia due to a Gain of Function Mutation in the Thrombopoietin (TPO) and JAK2 Gene as the Cause of Congenital Aspirin-Responsive Sticky Platelet Syndrome: Personal Experiences and Review of the Literature

Autosomal dominant hereditary Essential Thrombocythemia (ET) due to the gain of function mutation CG transversion in the splice donor of intron 3 in the TPO gene on chromosome 3q27 in a Dutch and Polish family is associated with marked increased TPO levels and Aspirin-responsive Sticky Platelet Syndrome (SPS). SPS is featured by typical clinical manifestations of aspirin responsive microvascular circulation disturbances including erythromelalgia and atypical transient ischemic attacks. Increase of large platelets in blood smears and large mature megakaryocytes with hyperploid nuclei in a normal cellular bone marrow were diagnostic for autosomal dominant hereditary ET (HET). The spectrum of platelet-mediated thrombophilia in HET is comparable to the aspirin responsive SPS in acquired JAK2 V617F positive ET. The affected members of the Dutch and Polish HET families showed no endogenous erythroid colony (EEC) formation. The first generation of the Dutch HET family, two females and one male had stable increased platelet counts, no features of PV, no splenomegaly during life-long follow-up. Three of four elderly family members in the Dutch HET family developed pancytopenia due to myelofibrosis at the age of 71 and 73 years in two, and evolution in acute myeloid leukemia at age 60 in one. These 3 HET patients were on long-term low dose aspirin to prevent SPS manifestations and not treated cytoreductive agents indicating that evolution of ET into myelofibrosis (MF) and leukemia belong to the natural history of TPO-induced HET. In the congenital HET caused by gain of function mutation in the TPO and the JAK2 gene ( JAK2 V617I and JAK2 R564Q ) the responses of mutated CD33 and CD34+ cells to TPO are increased, but the responses to EPO were normal thereby explaining why HET caused by heterozygous germline TPO and JAK2 mutations are associated with the biological characteristics of ET without PV features.

MR mammography of a primary squamous cell carcinoma of the breast: a case report

A case of a primary squamous cell carcinoma of the breast in a patient with synchronous contralateral invasive ductal adenocarcinoma is reported. To our knowledge, no dynamic MR mammography of this pathology is described in the literature. On MR, it presented as a mainly non-enhancing, partially cystic mass with an enhancing irregular peripheral rim. In the differential diagnosis of a mass with unsharp margins and an irregular border of the cystic or the non-enhancing area on MR mammography, a primary squamous cell carcinoma must be included.

Bone Marrow Features and Natural History of BCR/ABL-PositiveThrombocythemia and Chronic Myeloid Leukemia Compared to BCR/ABLNegativeThrombocythemia in Essential Thrombocythemia and PolycythemiaVera

The Hannover bone marrow (BM) classification distinguished three phenotypes of BCR/ABL-positive CML: CML of common type (CML.CT), CML with megakaryocyte increase (CML.MI) and CML with megakaryocyte predominance (CML.MP). BCR/ABL-positive essential thrombocythemia (Ph-positive ET) is featured by CML.MP bone marrow picture of small monolobulated megakaryocytes and is part of the CML spectrum as a malignant disease (neoplasia) with an obligate transition into acute leukemia of near to 100% after 10 years follow-up. The Hannover BM classification distinguished three primary prefibrotic BCR/ABL-negative (Ph-negative) myeloproiferative disorders (MPD)s: essential thrombocythemia (ET), polycythemia vera (PV) and chronic or primary megakaryocytic granulocytic myeloproliferation (CMGM/PMGM). The incidence of blasts crisis is low in the Phnegative MPDs ET, PV and CMGM. The risk of myelofibrosis is high in CMGM/PMGM, moderate in PV but low in Ph-negative ET. In BCR/ABL-positive thrombocythemia the platelets are small and indolent (non-reactive) and megakaryocytes are smaller than normal with hypolobulated nuclei caused by BCR/ABL induced maturation defect. BCR/ABL-positive thrombocythemia does not present erythromelalgic thrombotic or bleedings manifestations at increased platelet count in excess of 400 to 1500 × 109/L. The platelets and megakaryocytes in BCR/ABL-negative ET and PV are large due to growth advantage caused by constitutively activated by the JAK2V617F or MPL515 mutation. JAK2 and MPL mutated thrombocythemias are associated with a high risk on aspirin responsive plateletmediated inflammation and thrombosis in the end-arterial circulation (platelet thrombophilia).

WHO Clinical Molecular and Pathological (WHO-CMP) Features of Congenital MPLS505N and the Acquired MPLW515l/K Mutated Essential Thrombocythemia and Myelofibrosis

We analysed the clinical and hematological features in 41 patients of seven families, including 21 ET patients with a proven MPLS505N mutation and 20 relatives with thrombocythemia reported in the medical records. Out of the 41 MPL S505N mutated individuals 15 major thrombotic episodes in 14 members (34%) were reported as Budd-Chiari syndrome age 17 in 1, deep vein thrombosis leg age 41 in 1,ecclampsia and fetal in 1, stroke at ages 43, 72, 76 and 80 in 4 and myocardial infarction at ages between 31-81 years, median 52 years. Fourteen out of 21 well documented MPLS505N mutated ET patients had no splenomegaly and were free of major thrombosis during follow-up at ages between 2 and 76 years (mean 31 years). Eight MPLS505N mutated patients had myelofibrosis (MF) from grade MF1 in 5 to grade MF2 in 3 at ages between 28-80 years (mean 48 years), which was associated with mild to moderate splenomegaly (spleen length diameter 14.5 to 18 cm). Six anemic cases at hemoglobin levels between 10 and 11.9 g/dL had platelet counts between 317 and 963 × 10 9 /L. Among 15 family members 9 died from thrombosis in 3, hypocellular myelofibrosis (two of them at age 76 and 80 years) in 3, and cancer or undefined in 3 cases. The maximum life expectancy of MPLS505N family members with thrombocythemia was 50% at 80 years, and 90% at 80 years of non-affected family members without thrombocythemia. The clinical presentation in 30 ET patients with acquired MPL 505N mutation (9 males and 21 females, age 22-84 (mean 56 years of whom 18 had the W 515L and 12 the W 515K ) was featured by a high incidence of major arterial event in 23%, venous thrombosis in 10%, aspirin responsive microvessel disturbances in 60%, and major hemorrhage in 7%. The only abnormal laboratory finding in MPL mutated ET was increased platelet counts, 956+331 × 109/L in all and slight splenomegaly in 5 (17%). Bone marrow histology from patients ET carrying the MPL 505N mutation consistently displayed a normocellular bone marrow with clustered small and large to giant megakaryocytes with hyperlobulated stag-horn nuclei and no features of polycythemia vera (PV) in blood and bone marrow.

Myelofibrosis is a Secondary Event in JAK2 Trilinear Myeloproliferative Neoplasm (MPN) and in CALR and MPL Thrombocythemia: Implications for Novel Treatment Options of Prefibrotic MPN

JAK2V617F PV is a trilinear myeloproliferative neoplasm preceded by erythromelalgic thrombocythemia followed by myeloproliferative myeloid metaplasia of spleen and bone marrow and secondary myelofibrosis. The CALR and MPL mutated JAK2 wild type thrombocythemia complicated by myelofibrosis (MF) and agnogenic myeloid metaplasia (AMM) have no features of polycythemia vera (PV) are not primary or agnogenic anymore. The natural history of CALR and MPL thrombocythemia and secondary bone marrow fibrosis clearly differ fromJAK2V617F trilinear essential thrombocythemia (ET), PV, post-ET and post-PV secondary myelofibrosis. Evolution of anemia, splenomegaly and myelofibrosis in MPL, CALR thrombocythemia and JAK2V617F trilinear thrombocythemia and polycythemia vera (TPV) should be evaluated separately simple because treatment options differ.

The European clinical, molecular and pathological (Euro cmp → CMP) and WHO-CMP criteria of the myeloproliferative disorders 1940-2008 and myeloproliferative neoplasms 2008-2015

The 1990 Hannover Bone Marrow Classification separated Ph1+ CML from the Ph1myeloproliferative neoplasms (MPN) essential thrombocythemia (ET), polycythemiavera (PV) and chronic or primary megakaryocytic granulocytic myeloproliferation (CMGM/PMGM). The 2000-2008 European Clinical Molecular and Pathological (ECMP) criteria discovered 3 variants of thrombocythemia: ET with features of PV (prodromal PV) versus “true” normocellular ET and hypercellular ET associated with CMGM/PMGM without features of PV, MDS or CML. The 2008 World Health Organization (WHO)-ECMP and 2007-2015 WHOECMP MPN classifications defined three phenotypes of JAK2V617F mutated ET: normocellular ET (WHO-ET), hypercelluar ET due to increased erythropoiesis (prodromal PV) and ET with hypercellular megakaryocytic-granulocytic myeloproliferation (ET.MGM) or masked PV. JAK2 wild type MPL515 mutated ET is the second distinct thrombocythemia featured by clustered giant megakaryocytes with hyperlobulated stag-horn-like nuclei, in a normocellular bone marrow consistent with the diagnosis of “true” ET. JAK2/MPL wild type hypercellular ET is the third distinct thrombocythemia characterized by clustered larged immature dysmorphic megakaryocytes and bulky (bulbous) hyperchromatic nuclei consistent with CMGM/PMGM. Correspondence to: Jan Jacques Michiels, MD, PhD, Investigator, Senior Internist, International Hematology and Bloodcoagulation Research Center, Goodheart Institute and Foundation in Nature Medicine, European Working Group on Myeloproliferative Neoplasms, Erasmus Tower, Veenmos 13, 3069 AT Rotterdam, The Netherlands, Tel: +31-62-6970534; E-mail: goodheartcenter@upcmail.nl