Intravascular large B‐cell lymphoma (IVLBCL) is a distinct disease, but the neoplastic PD‐L1 expression on tumor cells may vary among cases. We evaluated 10 IVLBCL autopsy cases for neoplastic PD‐L1 expression, and had positive results in two cases. In one case, neoplastic PD‐L1 expression (SP142, 28‐8, and E1J2J clones) was dependent on the organ and anatomical site (capillaries vs. vessels) of the tumor tissue. Neoplastic PD‐L1 expression was found in tumor cells located in capillaries in the central nervous system, pituitary gland, kidneys, lung, and gastrointestinal tract; sinuses/sinusoids of the spleen, liver, bone marrow, and lymph nodes; and an extravascular location. However, this expression was not detected in tumor cells located in the adrenal gland, thyroid gland, pancreas, ovaries, uterus, pleura, and small or larger‐sized vessels of the lung. The other case showed constant neoplastic PD‐L1 expression on the tumor cells, and in addition to the affected organs, capillaries, and vessels with two anti‐PD‐L1 antibodies (28‐8 and E1J2J, but not SP142). The divergence and heterogeneity of neoplastic PD‐L1 expression were clearly demonstrated in our cases. To the best of our knowledge, this is the first description of divergent neoplastic PD‐L1 expression among the affected organs and anatomical sites in IVLBCL.

Intravascular large B-cell lymphoma (IVLBCL) is a rare and clinically distinctive entity characterized by the almost exclusive growth of large cells within the lumen of blood vessels in particular capillaries. Reports of this peculiar disease, do not commonly address the PD-L1 expression on IVLBCL tumor cells. Here, we describe a 51-year-old Japanese woman who presented with rapidly progressive cognitive decline and higher brain dysfunction. CT scan and MRI revealed multiple ischemic foci in the cerebral hemispheres, ground-glass opacity in the lungs, and splenomegaly. Random skin biopsy for IVLBCL diagnosis yielded negative results. The patient experienced a rapidly deteriorating clinical course with no treatment, and died from the disease after 3 months of hospitalization. Post-mortem examination revealed systemic intravascular plugging of lymphoma cells, without mass lesions in the central nervous system or in visceral organs such as the lungs, liver, pituitary gland, ovaries, and uterus. The tumor cells were positive for CD10, CD20, BCL2, BCL6, and MUM1, but not other lineage-specific markers. Notably, the tumor cells showed strong PD-L1 expression. Our case was diagnosed as IVLBCL with neoplastic PD-L1 expression. These findings suggest that PD-L1 is associated with immune evasion of IVLBCL and may play a role in the pathogenesis and peculiar biological behavior of this unique disease. Additionally, PD-L1 may represent a possible therapeutic target for immune check-point inhibitors.

Objective: We report a patient who underwent thrombectomy for acute bilateral internal carotid artery occlusion (ICAO).Case Presentation: A 76-year-old female presented consciousness disturbance. Although warfarin had been administered after prosthetic replacement, it was discontinued due to gastrointestinal hemorrhage. MRI showed bilateral ICAO and right-dominant ischemic changes involving the bilateral hemispheres. Radiological findings indicated acute occlusion of the right internal carotid artery (ICA), and chronic occlusion of the left ICA was primarily considered; however, revascularization was conducted with considering the possibility of bilateral occlusion. Thrombectomy was performed and recanalization of the bilateral ICAs was achieved. However, ischemia progressed, leading to extensive cerebral infarction. Conclusion:Thrombectomy for bilateral ICAO was performed although the outcome was unfavorable. Acute bilateral ICAO contains poor prognosis although it is indispensable to appropriately diagnose, evaluate, and select therapeutic strategy. A proper management for bilateral ICAO awaits further investigation.

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