Complete and long-lasting cytologic and molecular remission of FIP1L1-PDGFRA-positive acute eosinophil myeloid leukaemia, treated with low-dose imatinib monotherapy.

Myeloproliferative neoplasms associated with FIP1L1-PDGFR rearrangements represent a rare subset of myeloid and lymphoid malignancies, characterised by the presence of eosinophilia and abnormalities of PDGFRA, PDGFRB or FGFR1 genes. The fusion product of such genes is a tyrosine kinase oncoprotein sensitive to imatinib, which to date results to be the standard of care for FIP1L1-PDGFRA-positive chronic myeloproliferative disorders with eosinophilia. However, the coexistence of FIP1L1-PDGFRA rearrangement associated with acute myeloid leukaemia is extremely rare. Here, we report a rare case of FIP1L1-PDGFRA-positive acute myeloid leukaemia, with marked peripheral blood and bone marrow eosinophilia, treated with low dose of imatinib monotherapy, achieving a rapid and long-lasting complete cytologic and molecular remission, without need for intensive chemotherapy.

Eosinophilia in a cat with acute leukemia.

A 4-year-old castrated male domestic shorthaired cat with a history of vomiting and anorexia was diagnosed with leukemia with marked hepatic and splenic infiltration and concurrent eosinophilia with marked tissue infiltration. Despite thorough immunocytochemical and immunohistochemical immunophenotyping, the cell lineage of the leukemia was not identified.

Distinction of eosinophilic leukaemia from idiopathic hypereosinophilic syndrome by analysis of Wilms' tumour gene expression.

In patients presenting with immature eosinophilic precursors it is notoriously difficult to distinguish acute eosinophilic leukaemia (EoL) from the benign idiopathic hypereosinophilic syndrome (HES), based on morphological, cytochemical and immunophenotyping criteria, alone. Cytogenetic analysis or fluorescence in situ hybridization (FISH) can help in discriminating between these rare haematological disorders, but often treatment decisions cannot wait for the results of these time-consuming techniques. Recently, we and others found Wilms' tumour (WT1) gene expression to be increased in virtually all patients with acute leukaemias, whereas normal haemopoietic progenitors express the WT1 gene at much lower levels or not at all. To determine whether detection of WT1 gene expression is useful to distinguish EoL from HES patients, we analysed, by RT-PCR, bone marrow or blood mononuclear cells from EoL (n=3), HES (n=3) and reactive eosinophilia patients (n = 4) for WT1 gene expression. Using our WT1-RT-PCR protocol, we found WT1 gene expression to be restricted to EoL patients. By detecting WT1 mRNA transcripts in the cerebrospinal fluid using RT-PCR, we were also able to diagnose isolated CNS-relapsed leukaemia, initially confused with bacterial meningitis, in an EoL patient. In conclusion, we show that WT1-RT-PCR is a powerful complementary diagnostic tool to distinguish acute eosinophilic leukaemia from the hypereosinophilic syndromes. This observation needs confirmation in a larger series of EoL and HES patients.

[Hypereosinophilic syndrome].

Ten HES cases, which satisfied the Chuside criteria are reviewed. We found several types of HES--mild forms, often accompanied by edema, and more severe forms accompanied by vascular, lung and heart disorders. It is not necessary to treat some milder forms while the more severe forms often respond to large dose of prednisolone. Now that the diseases, which share a common hypereosinophilic factor, have been defined and HES is being seen in variants of various diseases, the concept of HES has reached a turning point. The administration of appropriate treatment to the particular individual case appears to be advisable.

[Eosinophilia in malignant tumors]. / Eosinofili ved maligne tumorer.

The article presents two cases of malignant tumour and eosinophilia and reviews the literature on this condition. It is associated with disseminated disease and indicates a poor prognosis. Current knowledge supports the view that eosinophilia in malignant tumours is caused by a tumour-produced ectopic hormone-like substance which directly stimulates the growth of the eosinophilic granulocytes in the bone marrow.

[Is hypereosinophilic syndrome a potentially malignant condition?]. / E la sindrome ipereosinofila una condizione potenzialmente maligna?

The existence of eosinophilic leukemia (EL) has been controversial since it was first described. Recently, some authors have suggested that EL is part of a spectrum of eosinophilic diseases termed hypereosinophilic syndrome (HS). EL diagnosis is very difficult, especially if abnormal chromosome are not present, because HS comprises multiple disease entities of unclear etiology with the common features of prolonged eosinophilia of undetectable cause and organ system dysfunction. We present a case of HS whose findings are consistent with a leukemic process. For two years the patient showed only sharp hypereosinophilia; his clinical course was then marked by signs and symptoms of granulocytic sarcoma (GS), an extramedullary tumor composed of granulocytic precursor cells. GS as a complication of EL was described and in some cases the diagnosis of leukemia was made only on the basis of the GS complication. The formation of eosinophilic GS also suggests a diagnosis of LE in our case of HS. Finally, we always consider HS as a potential malignant disease.

[A case of eosinophilic leukemia]. / Przypadek bialaczki kwasochlonnej.

The clinical course and diagnostic difficulties in a case of eosinophilic leukaemia are described. For a long time period the case showed clinical manifestations of a hypereosinophilia syndrome. Shortly before death clinical signs of leukaemia developed, and the diagnosis was confirmed on autopsy.

[Eosinophilic leukemia]. / Eosinofilní leukémie.

On the example of a patients with eosinophil leukaemia, which at first was manifested as eosinophilia in the peripheral blood stream and bone marrow without involvement of other organs and only after three years acquired the character of malignant growth, the authors draw attention to difficulties in the differential diagnosis of hypereosinophil syndrome. At the same time the authors review briefly views on the origin of eosinophil leukaemia, morphological and cytogenetic findings considered useful as evidence of this rare type of leukaemia.