Acquired Amegakaryocytic Thrombocytopenia Misdiagnosed as Immune Thrombocytopenia: A Case Report

Transient Acquired Amegakaryocytic Thrombocytopenia in the Setting of Severe Sepsis: A Case Report

Acquired amegakaryocytic thrombocytopenia (AATP) is a rare disorder in which severely low platelet levels occur due to reduced or complete absence of megakaryocytes in the bone marrow. The pathophysiology of this disease is not fully understood, although anti-thyroid peroxidase antibodies (anti-TPO) binding to cellular-myeloproliferative leukemia (c-mpl) receptors is a proposed mechanism. Currently, no standard published guideline for treatment exists, but immunosuppressive therapies have been used based on the proposed mechanism and associated conditions. We present a case of a 57-year-old male who presented to the hospital with a 3-day history of progressive weakness and dysphagia. He had recently been discharged from an outside health system after evaluation for suspected gastrointestinal bleeding, although esophagogastroduodenoscopy and colonoscopy did not uncover a source of bleeding. Fifteen days later, he was admitted to our hospital for septic shock and acute renal failure with suspected lower gastrointestinal bleeding (melena on presentation). He was found to have a rapidly declining platelet count with a nadir of 0. Due to severe thrombocytopenia, filgrastim was administered. A bone marrow biopsy revealed findings consistent with amegakaryocytosis with otherwise preserved cell lines. Hematologic labs improved with the initiation of appropriate treatment for severe sepsis. After performing an extensive workup, the likely etiology of transient AATP in this case was severe sepsis-induced immune dysregulation and bone marrow suppression.

Successful avatrombopag combined with cyclosporine treatment for carboplatin/pegylated liposomal doxorubicin/bevacizumab-induced acquired amegakaryocytic thrombocytopenia in a patient with recurrent ovarian cancer: case report

Carboplatin/pegylated liposomal doxorubicin/bevacizumab is an accepted standard anti-cancer treatment option for recurrent ovarian cancer. However, the occurrence of adverse events associated with this therapeutic regimen limits its continued clinical use. Among these adverse events, acquired amegakaryocytic thrombocytopenia is a rare but often potentially life-threatening adverse effect, and is intolerant to multiple treatment approaches. We report, for the first time, the successful treatment using avatrombopag combined with cyclosporine in one case of carboplatin/pegylated liposomal doxorubicin/bevacizumab-induced acquired amegakaryocytic thrombocytopenia, which was refractory or intolerant to glucocorticoids, intravenous immunoglobulin, recombinant human thrombopoietin, androgen, and even thrombopoietin receptor receptor agonist eltrombopag and herombopag. To date, this case manifests as normal platelet counts that are independent of transfusion. Our findings suggest that this combination is a potential and valuable alternative in acquired amegakaryocytic thrombocytopenia.

Novel THPO variant in hereditary thrombocytopenia: A potential candidate variant for predisposition to myeloid neoplasm

Hereditary thrombocytopenia is a heterogeneous group of congenital disorders with a wide range of symptoms depending on the severity of platelet dysfunction or thrombocytopenia. Because of its clinical phenotypes and the bone marrow morphology associated with this condition, hereditary thrombocytopenia can be misdiagnosed as primary immune thrombocytopenia and myelodysplastic syndrome. Therefore, genetic evidence is necessary for the accurate diagnosis of hereditary thrombocytopenia. Refractory cytopenia of childhood is a subgroup of myelodysplastic syndrome that was added to the World Health Organization classification in 2008. To investigate the germline and somatic variants associated with refractory cytopenia of childhood, we performed targeted multigene sequencing in three patients with refractory cytopenia of childhood. Of the three patients, one progressed from megakaryocytic hypoplasia with thrombocytopenia, and targeted multigene sequencing revealed THPO variants in this patient and his sister. We propose that the monoallelic deletion of THPO is a potential candidate for germline predisposition to myeloid malignancy.

Pembrolizumab-Induced Acquired Amegakaryocytic Thrombocytopenia and Successful Combination Treatment With Eltrombopag, Romiplostim and Cyclosporine: A Brief Communication

Pembrolizumab is a humanized antibody directed against the programmed death-1 receptor on the cell surface, resulting in a T-cell-mediated immune response against tumor cells that can be complicated by immune-related adverse events. Here we present a novel case of pembrolizumab-induced acquired amegakaryocytic thrombocytopenia (AAT) in a patient with metastatic nasopharyngeal carcinoma. AAT is an incredibly rare and challenging entity for which there is no standardized treatment. We discuss our therapeutic approach using a calcineurin inhibitor and thrombopoietin receptor agonists for successful treatment of AAT and resumption of multiagent cytotoxic chemotherapy.