Molecular Defects in Chronic Myeloproliferative Disorders

Review of the myelodysplastic syndrome as a cause of group V pulmonary arterial hypertension: an orphan disease in an orphan pulmonary hypertension group

The coexistence of MDS and pulmonary hypertension (PH) is not a common finding and often goes unnoticed because symptoms such as dyspnea can be confused with the underlying pathology. The annual incidence of idiopathic pulmonary arterial hypertension (PAH) is only around 0.2 cases per 100,000 inhabitants, while MDS is 1 to 8 cases per 100,000 inhabitants. This review summarizes the clinical manifestations, functional respiratory tests, hemodynamic parameters using right heart catheterization, and imaging findings using echocardiography and tomography of pulmonary hypertension in myelodysplastic syndrome. We centered our discussion on the diagnosis of these patients within the hematologic disorders, especially in patients with the detriment of the functional class, as we were not used to looking for this diagnosis as a first choice. Several specialties dealing with patients with hematologic disorders (internists, hematologists, family physicians, geriatrics, oncologists) will find helpful the contents of this review.

Clonal evolution of 8p11 stem cell syndrome in a 14-year-old Chinese boy: a review of literature of t(8;13) associated myeloproliferative diseases

We describe a case of coexisting BCR-ABL negative myeloproliferative disorder and precursor T-cell lymphoblastic lymphoma associated with t(8;13) involving FGFR1 at 8p11 in a 14-year-old boy who presented with generalized lymphadenopathy and an abdominal mass. JAK2 mutation and FIP1L1-PDGFRalpha were not detected. RT-PCR revealed the ZNF198-FGFR1 fusion transcript in both the bone marrow (BM) and lymph node (LN) of the patient at diagnosis. Of interest, reciprocal FGFR1-ZNF198 fusion transcript was demonstrated in the BM but not LN. Also differential clonal TcRgamma gene rearrangements in the BM and LN samples were observed. These findings provide novel insights into the genetic pathogenesis.

Myelodysplastic syndromes, chronic myeloproliferative diseases, and myelodysplastic/myeloproliferative diseases

This article reviews the major diagnostic criteria for the myelodysplastic syndromes, chronic myeloproliferative diseases, and myelodysplastic/myeloproliferative diseases. Perhaps the most important message this article intends to convey is that the proper diagnosis and classification of myelodysplastic syndromes, chronic myeloproliferative diseases, and myelodysplastic/myeloproliferative diseases requires a multidisciplinary approach that correlates morphologic findings with clinical, genetic, and other laboratory information. Thus, the pathologist is central to the diagnosis of these disorders. Not only do pathologists have the morphologic skills to interpret peripheral blood and bone marrow aspirate smears and bone marrow biopsy specimens properly, but they often are responsible for interpretation of flow-cytometry and molecular genetic data as well. Pathologists are therefore in the best position to determine whether all the individual pieces of data fit together for the diagnosis under consideration. An additional important theme in the paper is that "well-prepared" blood and bone marrow aspirate smears and "adequate, well-processsed" bone marrow biopsy specimens are essential for the diagnosis. In the author's opinion, inadequate specimens usually account for most of the difficulties encountered in the proper diagnosis of these diseases. It is hoped that when an excellent specimen is available, the guidelines contained in this article may provide the pathologist with assistance in arriving at the most appropriate diagnosis.

Unexplained pulmonary hypertension in chronic myeloproliferative disorders

AIM

To investigate the potential association between the chronic myeloid disorders (CMDs), including the chronic myeloproliferative disorders, and pulmonary hypertension (PH).

METHODS

Retrospective chart review of patients who had received diagnoses of both CMD and PH. Patients with a known cause of PH were excluded. The diagnosis of a CMD was based on established criteria. The diagnosis of PH was based on echocardiographic data or right heart catheterization data.

RESULTS

Twenty-six patients satisfied the criteria for both a CMD and PH. Twelve patients had myeloid metaplasia with myelofibrosis (MMM), 5 patients had essential thrombocythemia (ET), 6 patients had polycythemia vera, 2 patients had a myelodysplastic syndrome, and 1 patient had chronic myeloid leukemia. Twenty-two patients (92%) received treatment for their CMDs, which included therapy with hydroxyurea (18 patients), anagrelide (7 patients), and busulfan (3 patients). PH was diagnosed a median of 8 years after recognition of the CMD (range, 0 to 26 years). The median right ventricular systolic pressure (RVsys) was 71 mm Hg (range, 32 to 105 mm Hg). RVsys correlated with the platelet count in patients with MMM (r = 0.30) and ET (r = 0.6) and with the hemoglobin levels in patients with PV (r = 0.77). Treatment of CMD did not seem to affect the severity of the pulmonary artery pressures as measured by serial echocardiography. With a median survival time of 18 months after the diagnosis of PH, the cause of death in the majority of the patients was cardiopulmonary.

CONCLUSIONS

The current study suggests a higher than expected incidence of PH in patients with MMM, PV, and ET. Prognosis in such a setting is poor and may not be influenced by aggressive treatment of the underlying hematologic disorder.