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Herein, we report a case of plasmablastic lymphoma (PBL) and diffuse large B-cell lymphoma (DLBCL) that occurred concurrently in the large intestine. An 84-year-old female presented with a palpable rectal tumor and ileocecal tumor observed on imaging analyses. Endoscopic biopsy of both lesions revealed lymphomatous round cells. Hartmann’s operation and ileocecal resection were performed for regional control. The ileocecal lesion consisted of a proliferation of CD20/CD79a-positive lymphoid cells, indicative of DLBCL. In contrast, the rectal tumor showed proliferation of atypical cells with pleomorphic nuclei and abundant amphophilic cytoplasm, with immunohistochemical findings of CD38/CD79a/MUM1/MYC (+) and CD20/CD3/CD138/PAX5 (–). Tumor cells were positive for Epstein-Barr virus–encoded RNA based on in situ hybridization and MYC rearrangement in fluorescence in situ hybridization analysis. These findings indicated the rectal tumor was most likely a PBL. Sequencing analysis for immunoglobulin heavy variable genes indicated a common B-cell origin of the two sets of lymphoma cells. This case report and literature review provide new insights into PBL tumorigenesis.

Abstract IgG4‐related diseases are adverse events that occur after receiving treatment with immune checkpoint inhibitors (ICI). This study reports the first case of IgG4‐related retroperitoneal fibrosis after the administration of chemotherapy with nivolumab and ipilimumab (NI therapy). An 80‐year‐old man developed lower abdominal pain eight months after NI therapy was initiated. Although the primary lesion maintained its reduced size on computed tomography, there was an increase in the soft tissue shadows intensity around the abdominal aorta, bladder, and seminal vesicles, suggesting retroperitoneal fibrosis. Blood tests showed elevated IgG4 levels. Computed tomography‐guided biopsy of the retroperitoneum showed B cell‐dominant lymphocyte infiltration consistent with IgG4‐related retroperitoneal fibrosis and characteristic CD8‐positive lymphocyte infiltration, suggestive of the involvement of cytotoxic T cells. Based on the clinical, imaging, and pathological findings, the patient was diagnosed with IgG4‐related retroperitoneal fibrosis due to ICI. Immunotherapy discontinuation alone did not result in improvement; therefore, steroid therapy was initiated. In clinical practice, IgG4‐related retroperitoneal fibrosis can occur as an immune‐related adverse event when administering anti‐PD‐1 and anti‐CTLA‐4 antibodies for cancer immunotherapy. Early steroid therapy could be effective in controlling this immune‐related adverse event.

The article discusses the issue of rising cyber-attacks in East Asia and Japan, focusing on Japan Pension Service's loss of pension records through computer virus and cyber espionage. It states that the Japan's current cyber security includes signal intelligence (SIGINT) capabilities. It also discusses the Distributed Denial of Services (DDoS) attacks, Advanced Persistent Threats (APTs), and Cyber-Conventional Combination (CCC).