Divergence and heterogeneity of neoplastic PD‐L1 expression: Two autopsy case reports of intravascular large B‐cell lymphoma. Issue 3 (28th January 2019) - Sakakibara, Ayako
Abstract : 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.