Leukemia with megakaryocytic differentiation following essential thrombocythemia and myelofibrosis. Case report and review of the literature

Leukemias of megakaryocytic lineage are rare and heterogeneous clinical entities. The nomenclature published in the literature is confusing and perhaps inappropriate to designate these primary myeloproliferative disorders. We describe a patient with essential thrombocythemia who evolved through myelofibrosis and myeloid metaplasia to a final picture of leukemia with megakaryocytic differentiation in the peripheral blood. This case illustrates different aspects of a chronic myeloproliferative disorder where myelofibrosis and myeloid metaplasia are frequent but secondary events. We have reviewed the literature focusing on the role of clonal megakaryocytic proliferation in myelofibrosis and on the clinical characterization of leukemia with megakaryocytic phenotype. We also present our interpretation of the literature which indicates that a formal review of the nomenclature is urgently needed.

Expression of erythroid-specific genes in acute megakaryoblastic leukaemia and transient myeloproliferative disorder in Down's syndrome

Acute megakaryoblastic leukaemia (M7) and transient myeloproliferative disorder in Down's syndrome (TMD) are characterized by rapid growth of abnormal blast cells which express megakaryocytic markers. To clarify properties of the blast cells in M7 and TMD cases, we examined erythroid markers expression in blasts from six cases with M7 and seven cases with TMD in this study. Erythroid-specific mRNAs encoding gamma-globin and erythroid delta-aminolevulinate synthase were found to be expressed in blasts from most of these cases, indicating that majorities of the blasts in M7 and TMD cases have erythroid and megakaryocytic phenotypes. We also found that mRNAs encoding GATA-1 and GATA-2 are expressed in all these cases. These results suggest that M7 blasts and TMD blasts correspond to the erythroid/megakaryocytic bipotential progenitor cells.

Ultrastructural studies of the megakaryoblastic leukemias of Down syndrome

The ultrastructure of the leukemic cells in transient leukemia (six cases), myelodysplasia (five cases) and acute megakaryoblastic leukemia (one case) in patients with Down syndrome were studied. The cells were identified to be of megakaryocytic lineage by virtue of the expression of platelet glycoprotein GpIIIa, detected by immunogold labelling. In all patients, some of the leukemic cells had ultrastructural features of megakaryocytes, including ectoplasmic protrusions, demarcation membranes, and alpha granules. Differentiation was greatest in the cells of patients with transient leukemia. These studies provide a detailed assessment of the ultrastructural features of the leukemic cells in the megakaryoblastic leukemias of Down syndrome.

Mixed-lineage acute myeloid leukemia associated with a suprasellar dysgerminoma

An association between primary mediastinal germ cell tumors and hematologic malignancies has been recognized since 1985. We present a patient with a suprasellar germ cell tumor and an associated leukemia. A 20-year-old black female presented in December 1987 with a 6-month history of headaches and weight loss, confusion, polyuria, and polydipsia. Evaluation revealed hypernatremia, normal neurologic examination except poor recall, and an enhancing inhomogeneous suprasellar mass on cranial computed tomography. Biopsy of the mass diagnosed a dysgerminoma, which was treated with craniospinal radiation. In February 1988, the patient developed pancytopenia, which resolved with discontinuation of cimetidine and phenytoin. She did well until June 1988 when she presented with skin lesions over the trunk and extremities. Skin biopsy revealed a leukemic infiltration. She was admitted with a WBC 1,500/microliter (without blasts), Hb 11.6 g/dl, PLT 210,000 microliter. Bone marrow biopsy revealed hypercellularity with 50% blasts, demonstrating mixed-lineage acute myeloblastic leukemia (myelomonocytic-M4; megakaryoblastic-M7). The patient was induced with a standard Ara-C/daunorubicin regimen. Two weeks postinduction, she became septic and expired. An autopsy demonstrated leukemic involvement of the spleen, liver, bone marrow, and skin, without residual dysgerminoma. This represents the first reported case of suprasellar dysgerminoma associated with a mixed-lineage leukemia not related to chemotherapy.

Myelodysplasia and acute megakaryoblastic leukemia in Down's syndrome

In this report we describe the clinical and hematologic features of 23 cases of myelodysplasia (MDS) or acute megakaryoblastic leukemia (AMKL) occurring in Down's syndrome. MDS was characterized by thrombocytopenia, abnormal megakaryocytopoiesis, megakaryoblasts (< 30%) in the marrow and abnormal karyotype, the most common of which was trisomy 8, found in 7/15 patients with MDS. Three of five patients achieved a complete remission with low dose cytosine arabinoside, vincristine and retinyl palmitate. The high cure rate and the distinctive features of the leukemic process in these cases suggest that this type of MDS and AMKL are unique to patients with Down's syndrome.

A case of acute megakaryocytic leukemia with hematogones

A case of an infant male with Down's syndrome, pancytopenia, and a relative lymphocytosis is presented. A bone marrow aspirate and crushed marrow biopsy were evaluated by microscopy and flow cytometry. A population of immature lymphoid cells positive for CD10 (CALLA) and CD19 (Leu 12) was initially interpreted as suggestive of an acute lymphoblastic leukemia (ALL). However, a second bone marrow biopsy revealed morphologic features consistent with acute megakaryocytic leukemia (AMKL) with fibrosis. This diagnosis was supported by the flow cytometric study showing increased myeloid and megakaryocytic antigen-positive cells in the bone marrow and peripheral blood obtained after chemotherapy for ALL. This report presents evidence that the original lymphoid population represented hematogones, which were preferentially aspirated due to marrow fibrosis. There are no previous reports of hematogones identified at the presentation of an acute leukemia. It also emphasizes that the presence of hematogones with the resultant marker findings can be misleading. The diagnosis of ALL in pediatric patients should not be based solely on the presence of increased CD10-positive cells.

Megakaryoblastic leukemia presenting as a temporal bone granulocytic sarcoma. Case report

The unusual presentation of acute megakaryoblastic leukemia as a temporal bone granulocytic sarcoma in an infant without systemic manifestations of leukemia is reviewed. Leukemia should be considered in the differential diagnosis of skull and skull-based lesions since the appearance on neuroradiological imaging is not unique in this diagnosis. Surgical treatment, as in this case, is limited to obtaining tissue for diagnosis and draining the infection.

Invasive aspergillosis in leukemic children

Two cases of invasive aspergillosis are reported. Case 1, a 3-year-old boy with leukemic transformation of myelodysplastic syndrome, had an aspergillus infection in the hand, resulting in necrosis of the thumb. Case 2, an 18-year-old girl with acute megakaryoblastic leukemia, had an aspergillus skin infection on the wrist, accompanied by swelling and discoloration of the arm. In Case 2, angiography revealed a hypovascular lesion and vascular irregularity, suggesting that vessels were involved. Intraarterial infusion of urokinase and amphotericin B led to improvement of these symptoms in this patient. The combination of urokinase and an antifungal drug should be considered for intractable aspergillus infections involving the extremities.

[Acute megakaryoblastic leukemia associated with Sweet's syndrome, including review of the literature]

A case of Sweet syndrome (SS) associated with acute megakaryoblastic leukemia (AMKL) is reported. A 66-year-old male was admitted to Ashikaga Red Cross Hospital because of skin eruption and sore throat. His eruption was tender and erythema-like nature. He developed a spiking fever after admission. CBC revealed pancytopenia, and a bone marrow specimen showed increased megakaryoblasts and fibrosis. These blasts were shown to be CD41-positive by flow cytometric analysis. A diagnosis of AMKL was then made. Skin biopsy revealed infiltration of neutrophils without vasculitis, compatible with SS. Oral administration of prednisolone was begun which improved his skin lesions considerably. He was then treated with low dose Ara-C, which was however ineffective. The blasts increased in the peripheral blood and he died on the 72nd hospital day. There are 37 reported cases of SS associated with acute nonlymphocytic leukemia, and this is the first case report of SS associated with AMKL.

Characterization of an acute micromegakaryocytic leukaemia: evidence for the pathogenesis of myelofibrosis

The current hypothesis for the pathogenesis of myelofibrosis involves the intramedullary release of growth factors from defective or abnormal megakaryocytes. We describe a case of an acute micromegakaryocytic leukaemia, in a patient with chronic myelofibrosis, that provides additional evidence for this concept. The micromegakaryocytes, which reached 223 x 10(9)/l, were characterized morphologically by both light and electron microscopy, immunocytochemically and by platelet peroxidase activity. The cells were shown to have a mature cytoplasm, containing alpha granules and the associated proteins; vWF:Ag, fibrinogen, fibronectin and protein S. DNA analysis, by both a Seescan Solitaire Plus image analysis system and flow cytometry, revealed nuclear immaturity, with 92% of cells being diploid. Serum markers of connective tissue synthesis, namely carboxy terminal peptide of procollagen I (PICP), procollagen terminal peptide III (PIIIP) and laminin all increased significantly following transformation and were associated with an increase in platelet-derived growth factor (PDGF) and transforming growth factor-beta (TGF-beta). These observations support the current hypothesis for bone marrow fibrosis formation and provide, for the first time, a link between in vivo growth factor release, bone marrow stromal turnover and megakaryocyte mass. In addition, the release of biologically active TGF-beta may explain both the increased fibronectin and angiogenesis characteristic of myelofibrotic bone marrow.

Ultrastructural and ultracytochemical differences between megakaryoblastic leukemia in children and adults. Analysis of 49 patients

BACKGROUND

Acute megakaryoblastic leukemia (AMKL) has two peaks in distribution of incidence (in adults and children 1 to 2 years of age) and is frequently seen in children with Down syndrome. The current study was undertaken to disclose whether there were any differences between these groups.

METHODS

Electron microscopic and ultrastructural cytochemical features of 49 children and adults with a AMKL or chronic myelogenous leukemia (CML) in megakaryoblastic crisis were compared.

RESULTS

Blast cells from children with AMKL, including those with and without Down syndrome, had immature features lacking typical alpha granules and a demarcation membrane system (DMS). However, blast cells from patients with AMKL with Down syndrome had more theta, electron-lucent, and basophil-like granules, suggesting that the blast cells had more potential to differentiate into other cell lines than megakaryocytes. The AMKL blast cells of adult patients showed a higher percentage of platelet peroxidase (PPO) positivity than other subgroups, and they occasionally contained typical alpha granules and DMS. This indicated that the blast cells of adults with AMKL were more mature than those of children and CML in megakaryoblastic crisis.

CONCLUSIONS

By electron microscopic analysis, leukemic megakaryoblasts differed between children with AMKL with and without Down syndrome, adults with AMKL, and patients with CML in megakaryoblastic crisis.

Leukemia in Down syndrome: a review

The incidence of leukemia is higher in children with Down syndrome (DS) than in normals. In approximately 50% of cases the type of leukemia is acute megakaryoblastic leukemia (AMKL) and it occurs during the first 4 years of life. The leukemic cell also has features of erythroid progenitors and therefore appears to be a precursor cell with biphenotypic properties. In addition, newborns with DS frequently develop transient leukemia (TL), which is characterized by the presence of megakaryoblasts in the blood which disappear during the first 1-3 months of life. The incidence of this disorder is unknown although preliminary studies suggest that megakaryoblasts may be found frequently in the blood of DS newborns. TL does not occur in normal newborn infants. Although TL disappears spontaneously, many of these children will develop AMKL at 1-4 years of age. Recent surveys suggest that 20-30% of newborns with TL will develop AMKL. Preliminary evidence suggests that TL is a clonal proliferation, can be fatal, and may occur in a specific subgroup of DS children. The observations in this report are drawn from our own experience, reports in the literature, and data accumulated in the Canadian Down Syndrome Leukemia Registry.

Myelodysplastic syndromes (MDS) and acute myeloid leukemias (AML) with myelofibrosis

Acute myeloid leukemias (AML) and myelodysplastic syndromes (MDS) enter rarely in the differential diagnosis of myelofibrosis (MF). MF of marked intensity, resulting in either "dry taps" or non-representative smears, is encountered in approximately 10% of cases. MF may be observed in any type of AML, most frequently in acute megakaryoblastic leukemia (M7). Apart from some typical cases of MDS, MF is associated with cases of acute myelodysplasia with myelofibrosis (and a major megakaryocytic component). This syndrome has been described under various headings: acute or malignant myelosclerosis, and acute MF. It should be distinguished from M7 and from myeloproliferative syndromes.

Acute megakaryocytic leukemia in children. Clinical, immunologic, and cytogenetic findings in two patients

An unusual presentation of acute megakaryocytic leukemia (AMKL) is reported in two young children. The first child had a 10-day history of ptosis of the right eyelid as the initial manifestation of AMKL, a clinical picture not previously described in this variant of leukemia. Computed tomographic scanning showed multiple intracranial mass lesions, and the diagnosis of AMKL was confirmed by immunophenotyping of bone marrow blasts. The second child had Down syndrome and received alkylating agents and radiation therapy for treatment of metastatic rhabdomyosarcoma of the orbit. She had AMKL as second malignancy. Both patients had acquired chromosome 21 anomalies in their leukemic blasts. The first patient, constitutionally normal, had an i(21q) in his leukemic blasts; the patient with constitutional trisomy 21 had tetrasomy 21 and additional chromosomal changes. The clinical symptoms and the results of morphologic, immunologic, and cytogenetic studies are discussed.

Polyneuropathy in acute megakaryoblastic leukemia

Peripheral neuropathy is a rare complication in leukemia. The authors report a patient with acute megakaryoblastic leukemia (AMKL) and progressive symmetric polyneuropathy. Intense infiltration of leukemic cells in a peripheral nerve was observed at autopsy. This is the first report of AMKL with peripheral nerve involvement to the knowledge of the authors.

[Acute megakaryoblastic leukemia. Relation to trisomy 21]

Two cases of acute megakaryoblastic leukemia in a 4 month-old and a 13 year-old girl are described. In the first case who presented with a large hepatomegaly and portal fibrosis, the diagnosis was made from the surface phenotyping of megakaryoblasts; a trisomy 13, 14 and 19 and an extra chromosome X were present in the bone marrow. An electron microscopy study of megakaryoblasts was necessary to identify the second case. Both children died shortly after treatment (cytosine-arabinoside at low dosage in the first case and polychemotherapy in the second). The 51 other cases reported in the literature are reviewed.

Multiple myeloma and acute megakaryoblast leukemia in spent phase polycythemia vera

The spontaneous and simultaneous occurrence of multiple myeloma and megakaryoblast leukemia with myelodysplastic features in a case of spent phase polycythemia vera is well documented. In support of the morphologic characteristics of the bone marrow, immunocytologic studies show proliferation of monoclonal plasma cells and megakaryoblasts. The cytogenetic findings of 20q- and unbalanced t(1;7) are consistent with myelodysplastic and leukemic transformation of the bone marrow. These transformations expand observations on variable and spontaneous lineage commitments as the consequence of alterations of the hematopoietic stem cell clone. These data are in support of the changing insights in hematopoiesis as a process of ordered commitment of the stem cell with sequential lineage potentials.

Acute megakaryoblastic leukemia with massive myelofibrosis: complete remission and reversal of marrow fibrosis with allogeneic bone marrow transplantation as the only treatment

We report results of allogeneic bone marrow transplantation in an 8-year-old boy with acute megakaryoblastic leukemia characterized by intense fibrosis together with 20% blast cells in the bone marrow, who was transplanted without preceding chemotherapy for remission induction. Conditioning comprised cytosine arabinoside, cyclophosphamide and total body irradiation. The donor was his HLA-identical sister. The patient is well with minor chronic graft-versus-host disease and normal hematologic values 670 days post-transplant.

Acute megakaryoblastic leukemia in Down syndrome, following thrombocytopenia with antiplatelet antibody

We report a case of acute megakaryoblastic leukemia (AMKL) with antiplatelet antibody in a boy with Down syndrome. When the patient was admitted, his platelet count was 1.3 X 10(4)/mm3 and antiplatelet antibody in the plasma was detected. Two months after admission, blasts, which showed positive reaction to both antiplatelet monoclonal antibody and platelet peroxidase, increased.

Ultrastructural and ultracytochemical differences between transient myeloproliferative disorder and megakaryoblastic leukaemia in Down's syndrome

Ultrastructural and ultracytochemical studies were performed on blast cells from 12 Down's syndrome neonates with transient myeloproliferative disorder (TMD) and 13 Down's syndrome patients with megakaryoblastic leukaemia (MKL), in order to clarify the cytological characteristics of these cells. Average platelet peroxidase-positivity in blast cells of TMD patients was similar to that found in cases of MKL. Blast cells from subjects with TMD contained a number of different granules, namely, alpha granules, those that were myeloperoxidase (MPO)-positive, electron-lucent or basophil-like, and those containing membrane components or ferritin particles. On the other hand, granules found in the blast cells of MKL patients with Down's syndrome included the electron-lucent variety, those with membrane components and a few that were basophil-like, but not alpha and MPO-positive granules nor those containing ferritin particles. A demarcation membrane system was observed in blasts from the TMD group, but not in the MKL group. These findings suggest that blast cells in TMD patients differentiate to megakaryocytes, neutrophils, basphils and erythroblasts, while those in cases of MKL show limited differentiation to immature megakaryocytes, erythroblasts and, sometime, basophils. Such results correspond well with those of culture studies, in which TMD blasts were found to be precursors of various types of blood cells.