Rapid progression of acquired amegakaryocytic thrombocytopenia to aplastic anemia

Erratum: Ultrastructural alterations of megakaryocytes in thrombocytopenia: A review of 43 cases

Thrombocytopenia is a frequent occurrence in a variety of hematopoietic diseases; however, the details of the mechanism leading to low platelet count remain elusive. Megakaryocytes are a series of progenitor cells responsible for the production of platelets. Alterations in megakaryocytes in the bone marrow are a causative factor resulting in thrombocytopenia in varied diseases. Based on ultrastructural analysis of incidentally encountered megakaryocytes in 43 patients with blood diseases marked by low platelet counts, electron micrographs demonstrated that aberrant megakaryocytes predominated in idiopathic thrombocytopenic purpura, aplastic anemia, and myelodysplastic syndrome; autophagy, apoptosis, and cellular damage in megakaryocytes were a prominent feature in aplastic anemia. On the other hand, poorly differentiated megakaryocytes predominated in acute megakaryoblastic leukemia (AMKL) although damaged megakaryocytes were seen in non-AMKL acute leukemia. This paper documents the ultrastructural alterations of megakaryocytes associated with thrombocytopenia and reveals distinctive features for particular blood diseases. A comment is made on future avenues of research emphasizing membrane fusion proteins.

When Should We Think of Myelodysplasia or Bone Marrow Failure in a Thrombocytopenic Patient? A Practical Approach to Diagnosis

Thrombocytopenia can arise from various conditions, including myelodysplastic syndromes (MDS) and bone marrow failure (BMF) syndromes. Meticulous assessment of the peripheral blood smear, identification of accompanying clinical conditions, and characterization of the clinical course are important for initial assessment of unexplained thrombocytopenia. Increased awareness is required to identify patients with suspected MDS or BMF, who are in need of further investigations by a step-wise approach. Bone marrow cytomorphology, histopathology, and cytogenetics are complemented by myeloid next-generation sequencing (NGS) panels. Such panels are helpful to distinguish reactive cytopenia from clonal conditions. MDS are caused by mutations in the hematopoietic stem/progenitor cells, characterized by cytopenia and dysplasia, and an inherent risk of leukemic progression. Aplastic anemia (AA), the most frequent acquired BMF, is immunologically driven and characterized by an empty bone marrow. Diagnosis remains challenging due to overlaps with other hematological disorders. Congenital BMF, certainly rare in adulthood, can present atypically with thrombocytopenia and can be misdiagnosed. Analyses for chromosome fragility, telomere length, and germline gene sequencing are needed. Interdisciplinary expert teams contribute to diagnosis, prognostication, and choice of therapy for patients with suspected MDS and BMF. With this review we aim to increase the awareness and provide practical approaches for diagnosis of these conditions in suspicious cases presenting with thrombocytopenia.

Acquired amegakaryocytic thrombocytopenia as a rare cause of thrombocytopenia during pregnancy

A rare case of acquired amegakaryocytic thrombocytopenia (AATP) in a 35-year-old woman who presented with anaemia and thrombocytopenia at 22 weeks gestation. The first diagnostic impression was of an evolving aplastic anaemia; however, the patient was simultaneously diagnosed with severe vitamin B₁₂ deficiency in the setting of vegetarianism. Once the cyanocobalamin deficiency was corrected, a repeat bone marrow biopsy revealed an isolated depletion of megakaryocytes, which suggested the diagnosis of AATP. Supportive care was provided for her anaemia and thrombocytopenia and she delivered a healthy baby girl with a normal platelet count. The patient was subsequently started on romiplostim with steady improvement in her platelet counts. This rare AATP case presentation highlights the importance of a well-structured diagnostic approach to thrombocytopenia during pregnancy and supports the successful use of thrombopoietin agonists for the management of AATP.

A Case of Acquired Amegakaryocytic Thrombocytopenia with Anti-c-mpl Autoantibody: Comparison with Idiopathic Thrombocytopenic Purpura

Acquired amegakaryocytic thrombocytopenia (AAMT) is a rare disease that causes severe bleeding. The pathogenesis and treatment of AAMT have not yet been defined. We report the case of a 60-year-old woman diagnosed with AAMT, who presented with severe thrombocytopenia, gastroin-testinal bleeding, and significantly reduced bone marrow megakaryocytes. The patient was treated with methylprednisolone, cyclosporin, and intravenous immunoglobulin. After 2 weeks of treatment, her platelet count started to increase, and her bone marrow megakaryocyte count had normalized 3 months after diagnosis. At the time of diagnosis, the patient was seropositive for anti-c-mpl antibody but was seen to be seronegative once the platelet count recovered. In contrast, anti-c-mpl antibodies were not detected in the serum of 3 patients with idiopathic thrombocytopenic purpura. This case study suggests that anti-c-mpl antibody plays an important role in the development of AAMT, and that intensive immunosuppressive treatment is required for autoantibody clearance and recovery of megakaryocyte count.

Acquired Amegakaryocytic Thrombocytopenic Purpura Progressing into Aplastic Anemia

Acquired amegakaryocytic thrombocytopenic purpura (AATP) is a rare hematological disorder characterized by severe thrombocytopenia and a complete or near-to complete absence of megakaryocytes in the bone marrow, while granulopoiesis, as well as erythropoiesis are usually preserved. Although autoimmune mechanisms are believed to be causative, the exact underlying pathogenesis is not known. To date, only few cases have been reported and management of this disease remains controversial with immunosuppression being the treatment modality of choice in the majority of patients. In this article, we report a case of newly acquired AATP without an associated autoimmune disease, refractory to corticoids, intravenous immunoglobulin (IVIG) and second-generation TPO (thrombopoietin) agonists, which have recently been approved for the treatment of thrombocytopenia. Finally, in accordance with other reports, disease progression into aplastic anemia has occurred.

Acquired amegakaryocytic thrombocytopenia and red cell aplasia in a patient with thymoma progressing to aplastic anemia successfully treated with allogenic stem cell transplantation

Association of pure red-cell aplasia with thymoma is well documented. However, acquired amegakaryocytic thrombocytopenia (AAMT) has been rarely associated with thymoma with only five reported cases in literature. We report a patient with thymoma complicated by pure red cell aplasia (PRCA) and AAMT who progressed to develop aplastic anemia (AA). The patient was refractory to 10-months of immunosuppressive therapy with cyclosporine, prednisone, and antithymocyte globulin. She was eventually treated with allogeneic stem cell transplantation (allo-SCT). On Day +323 the patient continues to be transfusion-independent. This case illustrates how in patients with thymoma and AAMT may herald development of AA. This is also the first report of a patient with AAMT progressing to thymoma-associated AA being successfully treated with allo-SCT. The successful outcome suggests allo-SCT as a feasible option similar to other AA patients.

Danazol: an effective option in acquired amegakaryocytic thrombocytopaenic purpura

Acquired amegakaryocytic thrombocytopaenic purpura (AATP) is a rare haematological condition characterised by isolated thrombocytopaenia with normal other cell lines. It is often initially misdiagnosed as immune thrombocytopaenic purpura but has characteristic bone marrow findings of reduced megakaryocyte numbers. The optimal treatment of AATP is not clearly defined but revolves around immunosuppressive therapies. We report a case of successful treatment of AATP with danazol, an antioestrogenic medication. We also review the aetiologies and pathogenesis of the disorder and suggest that danazol should be considered as an effective alternative to potent immunosuppression in AATP.

"Almost bleeding to death": the conundrum of acquired amegakaryocytic thrombocytopenia

Acquired amegakaryocytic thrombocytopenia (AAT) is a rare hematological disorder causing severe thrombocytopenia and bleeding. Previous in vitro studies postulated both cell-mediated suppression of megakaryocytopoiesis in early megakaryocytic progenitor cells and humoral-mediated suppression by anti-thrombopoietin antibodies as possible etiologies of AAT. Patients with AAT usually present with severe bleeding and thrombocytopenia that is unresponsive to steroids and intravenous immunoglobulin (IVIG). Although standard guidelines have not been established for management of AAT, a few case reports have indicated a response to immunosuppressive treatment. The prompt recognition of this disease entity is essential in view of the substantial risk of morbidity and mortality from excessive bleeding. We report a case of AAT successfully treated with equine antithymocyte globulin (ATG) and cyclosporine (CSP).

Acquired pure megakaryocytic aplasia: report of a single case treated with mycophenolate mofetil

Acquired pure megakaryocytic aplasia (APMA) is a rare disorder in the field of hematological diseases. We report the case of a patient with APMA treated with mycophenolate mofetil and review the literature associated with this. Until today, very few cases of APMA have been reported and the disease etiology still seems to be unclear. There have been no reported cases of treatment of APMA treated with mycophenolate mofetil.

Durable remission following a third allogeneic stem cell transplantation in a patient with repeatedly relapsing SAA. The importance of stroma cells for sustained engraftment?

Diagnosis of acquired AATP which finally progressed to SAA was established in an eight-yr-old boy. PBSCT from an HLA-identical unrelated donor using high numbers of CD34+ selected stem cells was performed and resulted in complete remission for almost two yr. However, SAA reoccurred with 100% donor hematopoiesis and was reversed by a second CD 34+ selected PBSCT from the same donor. Declining blood cell counts after an interval of two yr indicated second relapse. Chimerism analysis in PB and BM aspirates revealed a small autologous cell population of 4-12% and 2-11%, respectively. Finally, a third transplantation with unmanipulated BM from the same donor resulted in sustained remission with 100% donor hematopoiesis. The patient is in complete remission for more than five yr following the third SCT. Late graft failure or late graft rejection known to occur after transplantation of highly purified CD34+ cells, or even graft exhaustion caused by stromal dysfunction due to the underlying disease necessitated a third transplantation. Regardless of the cause of relapse, transplantation of unmanipulated BM instead of highly purified PBSCTs led to a permanent and stable engraftment in a third attempt after two previous PBSCTs.

Successful treatment of acquired amegakaryocytic thrombocytopenia with cyclosporine in adult onset Still's disease

Acquired amegakaryocytic thrombocytopenia (AAT) is a rare disorder, characterized by severe thrombocytopenia and selective, marked decrease or absence of megakaryocytes in the bone marrow. We describe a 29-year-old female with adult onset Still's disease preceding a diagnosis of AAT and autoimmune hemolytic anemia, which was successfully treated with cyclosporine. This is the first case of AAT in a patient with adult onset Still's disease.

Acquired amegakaryocytic thrombocytopenic purpura

Acquired amegakaryocytic thrombocytopenia is an unusual hematologic disorder characterized by thrombocytopenia in association with markedly diminished bone marrow megakaryocytes. We report a case that responded to treatment with cyclosporine but not to IL-11. The bone marrow biopsy, repeated after resolution of thrombocytopenia, showed normal number of megakaryocytes.

Acquired amegakaryocytic thrombocytopenic purpura: review of a not very well-defined disorder

Acquired amegakaryocytic thrombocytopenic purpura (AATP) is a hematological disorder characterized by severe thrombocytopenia, probably due to an immunologically induced absence of megakaryocytes with a marked decrease or total absence of megakaryocytes in the bone marrow. AATP may be differentiated from other causes of peripheral destruction of platelets, such as immune thrombocytopenia (ITP). Currently, there are no standard treatments for AATP. However, immunosuppressive therapy including steroids, androgens, anti-thymocyte globulin (ATG), cyclophosphamide, cyclosporine A, immunoglobulins, splenectomy, and allogenic bone marrow transplantation (BMT) have all been utilized with varying degrees of success. However, a positive response in patients with AATP using steroids alone has rarely been reported in the literature.

Natural history of moderate aplastic anemia in children

BACKGROUND

Moderate aplastic anemia (MAA) in children is a rare, idiopathic condition of bone marrow insufficiency that can resolve spontaneously, persist for months or years, or progress to severe aplastic anemia (SAA). We evaluated the rate of progression to SAA.

METHODS

We reviewed the records of 136 children referred for evaluation of bone marrow failure from 1978 to 2002 at St. Jude Children's Research Hospital. MAA was defined by a hypocellular bone marrow (<50%) and 2 or 3 cytopenias (absolute neutrophil count <1,500/mm(3), absolute reticulocyte count <40,000/mm(3), platelet count <100,000/mm(3)) lasting at least 6 weeks.

RESULTS

Twenty-four patients met the criteria for MAA. At a median follow-up of 66 months (range, 10-293), 16 patients (67%) progressed to SAA, 5 (21%) had persistent MAA, and 3 (12%) had complete resolution of MAA. No risk factors for progression could be identified.

CONCLUSIONS

When childhood MAA is treated with supportive care alone, 2/3 of patients progress to SAA.

Acquired amegakaryocytic thrombocytopenia purpura and eosinophilic fasciitis: a long relapsing and remitting course

Acquired amegakaryocytic thrombocytopenia purpura (AATP) is a rare disorder of unclear etiology characterized by severe thrombocytopenia, preservation of erythroid and myeloid cell lines, and absence of megakaryocytes in the bone marrow. We report herein a patient who developed eosinophilic fasciitis preceding a diagnosis of AATP. Longitudinal follow-up and treatment of this individual show a relapsing and remitting disease course which appears closely related to the dosing of cyclosporine. Later in the treatment course, dosing of anti-thymocyte globulin (ATG) appeared to have important beneficial contributions in the management of this patient's disease.

Acquired pure megakaryocytic aplasia report of two cases with long-term responses to antithymocyte globulin and cyclosporine

Acquired pure megakaryocytic aplasia is a rare disorder defined by severe thrombocytopenia with no other hematologic abnormalities and absent, or severely decreased marrow megakaryocytes. The etiology may be immune suppression of megakaryocyte development. Two patients are described who both responded rapidly to a combination of antithymocyte globulin and cyclosporine and who remain in remission 13-20 months after discontinuation of cyclosporine. This regimen is well described for treatment of aplastic anemia and may also be effective for acquired pure megakaryocytic aplasia.