A 69-year-old woman with leukocytopenia and thrombocytopenia was referred to our hospital. Her bone marrow comprised 70.5% abnormal promyelocytes that were positive for myeloperoxidase/CD33/CD117 and CD13 (dim) and negative for CD2/CD34/CD56 and HLA-DR. Chromosome analysis of the bone marrow showed t (12;17;15) (p13;q21;q22), and fluorescence in situ hybridization revealed the PML-RARA fusion signal only on the derivative chromosome 15. The patient was diagnosed with acute promyelocytic leukemia (APL) with PML-RARA and was treated using all-trans retinoic acid (ATRA). In peripheral blood (PB), PML-RARA-positive polymorphonuclear cells (PMNs) appeared on the second week and became negative on the sixth week after treatment, whereas PML-RARA-negative PMNs started to increase in number on the sixth week. Molecular remission was confirmed on the 10th week. Quantitative evaluation of the differentiated leukemic cells of APL and recovered cells from normal hematopoiesis in PB can provide useful information for a safer induction therapy. No significant difference was noted in the kinetics of the leukemic cells under ATRA treatment as well as in the clinical features between our patient without RARA-PML and those with t (15;17), which is a cytogenetic evidence for the critical role of PML-RARA in the pathogenesis of APL.

Angioimmunoblastic T-cell lymphoma (AITL) is frequently associated with immunological abnormalities, such as hypergammaglobulinemia, autoimmune cytopenia, and the presence of various autoantibodies. Few reports on AITL have also described the development of myelofibrosis resulting from the invasion of lymphoma cells that produced various cytokines, including TGF-β. Interestingly, recent studies demonstrated that autoimmunity can directly cause autoimmune myelofibrosis (AIMF). Usually, bone marrow fibrosis associated with AIMF is rapidly improved by treatment. Here, we describe our experience with a case of AITL complicated with the presence of numerous autoimmune abnormalities, including positive Coombs, anti-nuclear antibody, anti-ds-DNA antibody, anti-phospholipid antibody, and cold agglutinin tests. The patient presented with severe bone marrow fibrosis (MF-3) at the initial diagnosis. After two courses of the CHASE therapy, myelofibrosis rapidly disappeared, and the autoimmune abnormalities were ameliorated. These findings suggest that the bone marrow fibrosis observed in this case was partly attributable to an AIMF-like mechanism.

An 85-year-old man presented with right eye ptosis and visual abnormalities. Due to a lack of abnormal findings on plain magnetic resonance imaging (MRI) and laboratory examination, prednisolone therapy was initiated, and ocular myasthenia gravis and ocular symptoms subjectively improved. However, anorexia and conscious disorder appeared during the same period, and he was hospitalized for scrutiny. After admission, left eye adduction disorder and bilateral abduction nerve paralysis were also observed. Enhanced MRI revealed cranial nerve and leptomeninx enhancement. Subsequently, the patient developed seizures and died on the 10^th day of hospitalization without being diagnosed. An autopsy revealed infiltration of B-cell lymphoma cells into the subarachnoid space, particularly in the parietal lobe. Similar infiltration was observed in the cerebellum, brainstem, spinal cord, and bilateral oculomotor nerve. Primary leptomeningeal lymphoma is a rare form of primary central nervous system lymphoma without simultaneous parenchymal brain lesions. Clinicians should be aware of this form of lymphoma and carefully monitor its possible occurrence, even when patients are already being treated for other neurological diseases.

A 76-year-old man presented with shortness of breath and the laboratory tests suggested anemia and reticulocytopenia. CBC showed only anemia, and the bone marrow aspiration smear demonstrated absence of erythroid hematopoietic cells. Consequently, pure red cell aplasia (PRCA) was diagnosed. Computed tomography (CT) showed mediastinal multiple lymph node enlargement and ground-glass opacity in both the lung fields. Biopsy specimens of the mediastinal lymph node showed mild follicular hyperplasia and polyclonal plasma cells proliferation in the interfollicular area. These findings suggest idiopathic multicentric Castleman disease plasma cell type (iMCD PC type). Ciclosporin (CyA) was administered but there was no clinical improvement after 6 weeks of therapy. Therefore, prednisolone (PSL) was started at 0.5 mg/kg/day and was very effective for the PRCA and MCD. A total of 3 cases of CD (2 cases of MCD PC type and 1 case of CD HV type) with PRCA have been previously reported. In the 2 cases of MCD PC type, anemia was improved using PSL combination therapy. However, in the single case of CD HV type, PSL was not effective and anemia was improved with CyA treatment. This case suggests the possibility of using PSL as the first-line drug for MCD PC type with PRCA.

A 64-year-old male presented with a rapidly growing anterior mediastinal mass during the clinical course of atypical chronic myeloid leukemia. A needle biopsy performed for suspected myeloid sarcoma revealed the presence of Aspergillus abscess. Early diagnosis of mediastinal abscesses, which are associated with a high mortality rate, can prevent the progression of severity. Infectious abscesses should be considered for prompt qualitative diagnosis in patients with mediastinal masses. Thymoma, germ cell tumor, and malignant lymphoma are the most common anterior mediastinal tumors, whereas infectious abscesses should also be considered when myeloid sarcoma is suspected in patients with an underlying myeloid tumor.