Acquired amegakaryocytic thrombocytopenic purpura (AATP) is a rare disorder characterized by severe thrombocytopenia associated with total absence or a selective decrease in bone marrow megakaryocytes. A 67-year-old male presented with a 2-month bleeding tendency. He was referred to our hospital because of severe thrombocytopenia. Bone marrow biopsy showed complete absence of megakaryocytes without dysplasia in cells of the myeloid and erythroid lineages. AATP was diagnosed. In addition, mild normocytic normochromic anemia and reticulocytosis were also observed and haptoglobin was below the detectable level. Coombs-negative autoimmune hemolytic anemia (AIHA) was diagnosed based on the high titer of RBC-bound IgG and negative direct and indirect coombs test results. He was first treated with cyclosporine 200 mg per day and subsequently with prednisolone but only slight temporary improvement was achieved. Administration of eight doses of rituximab 375 mg/m² per week ameliorated both thrombocytopenia and anemia. AATP should be considered in the differential diagnosis of thrombocytopenia, and immunosuppressive therapy is a potential first-line treatment. This is the first case report of AATP accompanied by AIHA successfully treated with rituximab.

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We describe a rare case of acute promyelocytic leukemia (APL) presenting with central nervous system (CNS) involvement at the time of initial diagnosis. A 58-year-old male was hospitalized with palpitations, dyspnea, high grade fever, photophobia, and disturbance of consciousness in March 2010. APL was diagnosed by bone marrow (BM) examination. The cytogenetic analysis of BM cells demonstrated t(15;17)(q22;q11), and PML-RARA chimeric gene was detected by reverse transcriptase-polymerase chain reaction assay. Magnetic resonance imaging of the brain revealed several high intensity regions in the cerebrum and cerebellum. CNS involvement was diagnosed based on the appearance of APL blasts in cerebrospinal fluid (CSF). The patient was treated with all-trans retinoic acid (ATRA), and systemic chemotherapy consisting of idarubicin and cytarabine according to the Japan Adult Leukemia Study Group (JALSG) APL 204 protocol. He was then treated with continuous intrathecal administration of cytotoxic drugs (methotrexate, cytarabine, prednisolone) after systemic chemotherapy, achieving complete remission (CR) in both BM and the CNS. To date, he has been maintained in complete molecular remission in both BM and the CSF for 28 months, to date.

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We report a case of myeloid/natural killer cell precursor acute leukemia. A 68-year-old man was diagnosed as having lymphoma in his neck, and was referred to our department for further examination and treatment. After admission, blastoid-cells appeared and increased rapidly in his peripheral blood. Cell marker analysis revealed that the blastoid-cells expressed CD7, CD56, CD33, and CD34. He was then diagnosed with myeloid/natural killer cell precursor leukemia. This form of leukemia was recently established as a distinct disease entity. Further clinicopathological evaluation and the establishment of treatment are necessary.

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Spontaneous rupture of the spleen is a rare but important complication in hematological malignancies. Without splenectomy, the mortality rate of these patients is nearly 100%. We present a blastic plasmacytoid dendritic cell neoplasm case with this complication. Nine days after initiation of chemotherapy, the patient had increased epigastric pain and a drop in hemoglobin. CT scan showed an enlarged spleen surrounded by hemorrhage. Spontaneous rupture of the spleen was diagnosed. Although the patient had severe bone marrow suppression due to chemotherapy, emergency splenectomy was performed and the patient recovered.

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