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At least 19 recordsLinked to original sources
PubMed1979

Loss of Rh antigen associated with acquired Rh antibodies and a chromosome translocation in a patient with myeloid metaplasia.

Myeloid metaplasia is a clonal disease of the marrow pluripotent stem cell in which a constant cytogenetic abnormality could result in an altered antigenic characteristic of hematopoietic cells. A 57-yr-old man who had acquired myeloid metaplasia at age 37 was noted to be Rh negative, although blood typing at age 33 was Rh positive. His erythrocytes reacted with anti-c and anti-e, typical for an Rh negative individual. Analysis of 11 metaphase bone marrow cells by G-banding revealed 46 chromosomes with a consistent anomaly in 100% of cells involving chromosomes 1 and 13. The changes were consistent with a reciprocal translocation, with break points at approximately 1p32 and 13q22, although break points at 1p13 and 13q14 were also possible. Since previous cytogenetic data have localized the Rh gene to the short arm of chromosome 1, our data indicate the Rh gene lies within the segment u13 leads to 1p32. Serum of this patient had circulating anti-D and anti-C antibodies. Consequently, this patient lost immunologic tolerance to a "self antigen" after losing the ability to express this antigen.

Chromosome Mapping↗
PubMed1988

Splenectomy in agnogenic myeloid metaplasia and postpolycythemic myeloid metaplasia. A study of 34 cases.

A retrospective analysis of 34 successive splenectomies in 137 patients with myelofibrosis was carried out. Indications, complications, and response to splenectomy were compared between 22 patients with agnogenic myeloid metaplasia (AMM) and 12 patients with postpolycythemic myeloid metaplasia (PPMM). Painful splenomegaly, refractory hemolytic anemia, and refractory thrombocytopenia were the common indications for surgery. The best results were obtained for painful splenomegaly. For the other indications, half to three fourths of the patients improved with splenectomy. An increased incidence of excessive hemorrhage, infected hematoma, and early mortality was more common in the PPMM group and was found to be connected with large spleens, prolonged bleeding time, and prominent thrombocytopenia. Persistent thrombocytosis after surgery was more common in the AMM group. Leukemic transformation seemed to be related to thrombocytosis and to prior therapy with alkylating agents. Median survival following splenectomy was 43 months in the AMM group and 32 months in the PPMM group. We conclude that splenectomy has a role in improving the quality of life by ameliorating mechanical discomfort and decreasing transfusion requirement in the late phase of AMM. However, in patients with PPMM, because of the high complication rate, splenectomy should be carefully considered for specific indications on an individual basis.

Adult↗
PubMed1998

Splenectomy and risk of blast transformation in myelofibrosis with myeloid metaplasia. Italian Cooperative Study Group on Myeloid with Myeloid Metaplasia.

An unexpectedly high incidence of blast transformation after splenectomy has been reported in patients with myelofibrosis with myeloid metaplasia. However, whether this was associated with spleen removal after adjustment for risk factors was not determined. We conducted a multicenter historical cohort study of patients with myelofibrosis with myeloid metaplasia diagnosed from January 1970 through January 1994. A total of 549 patients (325 men and 224 women from 22 to 92 years of age; median age, 63 years) were included in the final data set. The Cox's proportional-hazards model was used to identify factors associated with blast transformation and death. To further adjust for factors related to spleen removal assignment, a propensity score for splenectomy was estimated using recursive-partitioning analysis. Blast transformation developed in 78 patients (14.2%). Patients who underwent splenectomy developed more blast transformations than those who were not splenectomized (23 of 87 [26.4%] v 55 of 462 [11.9%]; P < .001). The cumulative incidence of blast transformation 12 years after diagnosis was 27.0% in nonsplenectomized patients and 55.0% in splenectomized ones (P = . 01). The risk factors independently predictive of blast transformation included prior splenectomy (relative risk = 2.61), platelet count less than 100 x 10(9)/L at diagnosis (relative risk = 2.45), and the presence of blasts in peripheral blood at diagnosis (relative risk = 2.31). The relative risk of blast transformation in splenectomized patients increased from 2.2 at 48 months from diagnosis to 14.3 at 12 years. Patients with the same propensity score for splenectomy showed a higher risk for blast transformation on the basis of having undergone splenectomy (P = .02). In conclusion, the risk of blast transformation is significantly increased in subjects who underwent splenectomy and appears to be independent of factors related to spleen removal assignment.

Adult↗
PubMed1991

Ultrastructure of bone marrow tissue in so-called primary (idiopathic) myelofibrosis-osteomyelosclerosis (agnogenic myeloid metaplasia). II. The myeloid stroma (hematopoietic microenvironment).

An ultrastructural study was performed on bone marrow tissue in 8 patients revealing early and late stages of so-called primary (idiopathic) myelofibrosis - osteomyelosclerosis (agnogenic myeloid metaplasia) to evaluate the constituents of the hematopoietic microenvironment (myeloid stroma). A survey of the stroma cells disclosed an overall increase, particularly in so-called undifferentiated (primitive - pluripotent), but also in transitional (fibroblastic) reticular cells and myofibroblasts. The most primitive reticular cells were characterized by their stellate aspect with elongated slender cytoplasmic processes traversing the interstitial space, and by the scarcity of organelles. The transition into a fibroblast was preceded by the appearance of branching cisternal structures of the rough endoplasmic reticulum, extensively developed Golgi fields and an abundance in mitochondria. Frequently, so-called myofibroblasts were encountered displaying bundles of filaments along the subplasmalemmal region. Extracellularly fibrillar material with an irregular cross-banding as well as microfibrils could be observed. The many vascular structures (sinusoids and capillaries) exhibited a multilayered basement membrane-like material including many fibrils and adventitial cells (pericytes, smooth muscle and transitional reticular cells) with numerous cytoplasmic processes. Undifferentiated and transitional reticular cells as well as myofibroblasts seem to form an integral part of the hematopoietic microenvironment in OMF and are assumed to play an important role for the evolution of the disease-specific myelofibrosis in this disorder.

Bone Marrow↗
PubMedDate not supplied

Myeloid metaplasia of the central nervous system in patients with myelofibrosis and agnogenic myeloid metaplasia. Report of 3 cases and review of the literature.

Foci of meningeal myeloid metaplasia were found in 3 of 11 consecutive autopsied patients with myelofibrosis and agnogenic myeloid metaplasia. The clinical and pathological findings in an additional seven published patients with agnogenic myeloid metaplasia who developed neurological manifestations due to pressue of hemopoietic tumors in the central nervous system are reviewed.

Aged↗
PubMed1994

Skin manifestation of agnogenic myeloid metaplasia.

Agnogenic myeloid metaplasia (AMN) with myelofibrosis is a clonal malignancy of the hematopoietic stem cell. The disease is characterized by increased endothelial cell and fibroblast proliferation, resulting in increased deposition of fibronectin, laminin, and collagen in the bone marrow. In advanced disease, extramedullary hematopoiesis (EMH) is invariably seen in the spleen and liver. The lymph nodes are also frequent sites of EMH, but other organs, especially the kidneys, arenals, lungs, pleura, ovaries, gastrointestinal tract, and dura, may also be involved. Skin manifestations are rare. They may present in several ways: erythematous plaques, nodules, diffuse or papular erythema, ulcers, and bullae. Histopathology of these lesions reveals cells from one or more myeloid lineage in the dermis, erythroid, or megakaryocytic series alone or in combination. In rare cases, all three cell lines are demonstrated.

Aged↗
PubMed1993

CD7, CD34-positive stem cell leukemia arising in agnogenic myeloid metaplasia.

Agnogenic myeloid metaplasia (AMM) is a chronic myeloproliferative disorder arising from a single hematopoietic cell. Approximately 5% of reported cases of AMM have terminated in leukemic crisis; however, the precise characteristics of the leukemic cells have rarely been reported. We report a case of AMM that occurred in a 42-year-old man and was complicated by leukemic transformation. The leukemic cells were morphologically lymphoblastoid cells with a negative reaction to peroxidase staining, and phenotypically characterized as CD7+, CD34+, HLA-DR+, CD4-, CD8-, CD10-, CD13-, and CD33-. Southern blot analysis revealed that T cell receptor-beta, gamma, and immunoglobulin heavy chain genes in leukemic cells were retained in germ-line configuration. These observations suggest that leukemic cells in our case involved early hematopoietic stem cells rather than those strictly committed to myeloid or lymphoid precursors. To our knowledge, this is the first report of stem cell leukemia arising in a patient with AMM.

Acute Disease↗
PubMed1997

Blood thrombopoietin, IL-6 and IL-11 levels in patients with agnogenic myeloid metaplasia.

Agnogenic myeloid metaplasia (AMM) is a disease characterized by bone marrow megakaryocyte hyperplasia and clusters of megakaryocytes, in which many of the megakaryocytes are atypical. In order to elucidate the mechanisms of megakaryocytosis, ELISA assays of blood levels of thrombopoietin (TPO), interleukin-6 (IL-6) and interleukin-11 (IL-11) were done in 45 patients with AMM and compared with normal volunteer controls. Higher blood TPO levels were found in AMM than in controls (P < 0.0001), and blood TPO levels were correlated with the degree of marrow fibrosis (P = 0.0078). Blood levels of IL-6 were also significantly higher in AMM, when compared with controls (P < 0.0001). However, no correlation was found between blood IL-6 levels and degree of marrow fibrosis. No correlation was found between either TPO or IL-6 and the number of blood platelet counts, the number of marrow megakaryocytes, WBC counts, or the degree of splenomegaly. Blood IL-11 levels were undetectable in most patients and no significant difference was found in AMM as compared to controls. The present study demonstrated that, while in idiopathic thrombocytopenic purpura (ITP) or aplastic anemia, blood TPO levels are relatively correlated with the numbers of platelet and/or megakaryocyte mass, blood TPO levels do not correlate with blood platelet counts, or marrow megakaryocyte mass in AMM. Therefore, in AMM, other mechanisms such as the number of TPO receptors on platelets or megakaryocytes, c-MPL receptor abnormalities, abnormal production of TPO mRNA and so on, will have to be studied. Furthermore, TPO may play a significant role in the pathogenesis of marrow fibrosis; IL-6 may be a factor in the development of marrow megakaryocytosis but its elevated blood levels may represent a secondary immune phenomenon; and IL-11 probably does not play a significant role in causing marrow megakaryocytosis in this disease.

Biomarkers↗
PubMed1994

Sarcoidosis and agnogenic myeloid metaplasia.

Agnogenic myeloid metaplasia (AMM) was recognized 3 years after a diagnosis of sarcoidosis in a 45-year-old man. This is the second reported instance of that association, and the 15th reported case in which systemic granulomata have been associated with a myeloproliferative disorder (MPD). In the client population at risk, this connection would be expected to occur by chance once in 1700 years. Therefore, it is unlikely that the association is fortuitous. Systemic granulomata may represent an immunologic response to antigens of neoplastic origin in MPD.

Humans↗
PubMed1994

Nephrotic syndrome associated with agnogenic myeloid metaplasia.

Agnogenic myeloid metaplasia (AMM), a myeloproliferative disorder of clonal origin, can affect the kidneys via several mechanisms. Associated disorders include asymptomatic interstitial extramedullary hematopoiesis, obstructive uropathy and nephrolithiasis. Currently, there are no descriptions of the nephrotic syndrome associated with AMM. We present a case of AMM associated with the nephrotic syndrome, a mesangial proliferative glomerular lesion and extramedullary hematopoiesis.

Aged↗
PubMed1992

Clonal analysis of agnogenic myeloid metaplasia.

Agnogenic myeloid metaplasia (AMM) is a chronic myeloproliferative disorder that leads to a sustained proliferation of megakaryocytes and an increase of reticulin fibers within the bone marrow. Blood and bone marrow samples from patients with advanced AMM with fully developed myelofibrosis as well as cases in the cellular phase of the disease were investigated for clonality. Clonality was studied by X-linked restriction length polymorphism in conjunction with DNA methylation patterns. Granulocytes and total bone marrow cells proved to be monoclonal in origin whereas at least a minor portion of the peripheral lymphocytes were not clonally derived. Our findings indicate that the cellular phase of AMM as well as the fully developed disease progressed to myelofibrosis represent a monoclonal proliferation of pluripotent hematopoietic stem cells.

Bone Marrow↗
PubMed1996

Current perspective in agnogenic myeloid metaplasia.

Agnogenic myeloid metaplasia (AMM) carries the worst prognosis among the chronic myeloproliferative disorders. Substantial bone marrow fibrosis, extramedullary hematopoiesis, anemia and hepatosplenomegaly are the characteristic features of the disease. AMM is currently incurable and the available treatment agents are mostly palliative and do not prolong life. Two pathogenetic processes are responsible for the impaired hematopoiesis and the clinical manifestations. The primary disease process is a clonal hematopoietic stem cell disorder which results in chronic myeloproliferation and atypical megakaryocytic hyperplasia. The secondary process of bone marrow fibrosis is the result of non-clonal fibroblastic proliferation and hyperactivity induced by growth factors abnormally shed from clonal megakaryocytes. Therefore, experimental treatment strategies may be directed towards either one or both of these disease processes. This report summarizes the current management options and new therapeutic endeavours.

Bone Marrow Examination↗
PubMed2000

Splenectomy in chronic myeloid leukemia and myelofibrosis with myeloid metaplasia.

Myelofibrosis with myeloid metaplasia (MMM) is a collective term that describes the related disorders AMM, PPMM, and PTMM. The chronic myeloid disorders include chronic myeloid leukemia, polycythemia vera, essential thrombocythemia, and agnogenic myeloid metaplasia (myelofibrosis). These disorders display varying propensities for pathologic enlargement of the spleen which can lead to mechanical discomfort, hypercatabolic symptoms, anemia, thrombocytopenia, and portal hypertension. Splenectomy has been found to be of little benefit in the early stages of chronic myeloid leukemia. Similarly, the benefit of splenectomy in advanced cases is limited to symptomatic palliation and treatment of delayed engraftment after allogeneic bone marrow transplantation. Although polycythemia vera and essential thrombocythemia are also characterized by splenomegaly, splenectomy is not considered a therapeutic option in the absence of transformation of the disease into myelofibrosis with myeloid metaplasia. Splenectomy has been studied most in myelofibrosis with myeloid metaplasia. Although there is no clear survival advantage to splenectomy in this disorder, the surgical procedure can result in substantial palliation of mechanical discomfort, hypercatabolic symptoms, portal hypertension, and anemia. However, the procedure is associated with an approximately 9% mortality rate, and the postsplenectomy occurrence of extreme thrombocytosis, hepatomegaly, and leukemic transformation is of major concern.

Humans↗
PubMed1981

Spontaneous "remission' of agnogenic myeloid metaplasia and termination in acute myeloid leukemia.

Acute myeloid leukemia developed in two men with well-documented agnogenic myeloid metaplasia 49 and 27 months, respectively, after initial diagnosis. Both men had spontaneous hematologic remissions of myeloid metaplasia 22 and 16 months prior to leukemic transformation. Neither patient received any precedent radiation or cytotoxic chemotherapy. The remissions and subsequent transformation to acute leukemia were documented by bone marrow aspiration, biopsy, and reticuloendothelial marrow scans, as well as in vitro cell cultures and cytogenetic study. A review of the literature revealed nine other patients who had conversion to acute leukemia in the absence of preceding radiation or cytotoxic chemotherapy. However, the hematologic remission prior to transformation to leukemia.

Bone Marrow↗
PubMed2002

Thalidomide treatment in myelofibrosis with myeloid metaplasia.

Myelofibrosis with myeloid metaplasia (MMM) is uniquely characterized by macroscopic bone marrow stromal changes that are believed to be both reactive and cytokine mediated. Furthermore, a prognostically detrimental increase in bone marrow angiogenesis has recently been demonstrated. These observations suggest a potential therapeutic role for agents that are inhibitory to angiogenesis as well as cytokines that are pathogenetically implicated in MMM. In a prospective study of 15 patients with MMM, thalidomide treatment, starting at a dose of 200 mg/d, resulted in increased platelet counts (12 of 15 patients), increased haemoglobin level (3 of 15), a modest decrease in spleen size (3 of 12), increased bone marrow megakaryopoiesis (5 of 9) and decreased bone marrow angiogenesis (2 of 9). Undesirable haematological effects included pericardial extramedullary haematopoiesis in one patient, marked leucocytosis in two patients and extreme thrombocytosis in three patients. The thrombocytosis occurred in both patients with post-thrombocythaemic myeloid metaplasia (PTMM) and was also associated with higher baseline levels of circulating CD34+ cells. Previously described toxicities of thalidomide were seen in the majority of patients and dose escalation to 400 mg/d was permitted in only two patients. In contrast, toxicity-related dose reductions to 50 mg/d did not appear to lessen drug efficacy. We conclude that thalidomide has both beneficial and potentially adverse biological activity in MMM. A lower dose of the drug might be more tolerable without compromising therapeutic value. Patients with PTMM and/or markedly increased circulating CD34+ cell counts might be susceptible to thalidomide-induced thrombocytosis.

Adult↗
PubMedDate not supplied

Palliative splenectomy in myelofibrosis with myeloid metaplasia.

Myelofibrosis with myeloid metaplasia (MMM) is a chronic myeloproliferative disorder in which the accumulation and growth of circulating myeloid progenitors in the spleen lead to pathologic enlargement of the organ with resulting mechanical discomfort, hypercatabolic symptoms, anemia, thrombocytopenia, and portal hypertension. Medical therapy and splenic irradiation may be of benefit in certain patients, yet many may still require splenectomy to palliate their symptoms. Although there is no clear survival advantage to splenectomy in MMM, the procedure can result in substantial palliation of symptoms. However, the surgical procedure is associated with an approximately 9% mortality rate, and the postsplenectomy occurrence of extreme thrombocytosis, hepatomegaly, and leukemic transformation is of major concern. The management of splenomegaly and the role of splenectomy in MMM are discussed in this review.

Disease Management↗