PMC8554327_01
Response in Case 1 treated with ILI and pembrolizumab. (A), Baseline clinical pictures of the numerous recurrent lesions. (B), 6-month follow-up demonstrating significant partial response in the infused limb. (C), CD3+ T cell infiltrate in leg soft-tissue biopsy of a responding lesion. (D), CD8+ T cell infiltrate. Immunohistochemistry images are presented at 20x magnification.
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f1
At presentation she had numerous (at least 12) lesions in the vicinity of her prior operations but no evidence of distant disease ( Figure 1A ). The patient had a partial response of 6 months duration ( Figure 1B ). A biopsy of one of the responding lesions showed a brisk lymphocytic infiltrate ( Figures 1C, D  ).
PMC8554327_02
Response in Case 2 treated with ILI and pembrolizumab. (A), Baseline CT scan with lesions noted. (B), 2-year follow-up scan demonstrating ongoing response both in infused limb and at distant site.
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f2
She presented one year after her 7th resection with recurrent disease, a 4.1cm x 2.9cm mass overlying the anterior tibia, a possible adjacent soft-tissue tumor nodule, and metastatic disease in an inguinal lymph node ( Figure 2A ). Both the lesion in the chemotherapy infusion field (tibia) and outside the infusion field (inguinal lymph node) demonstrate ongoing radiologic complete response at two years ( Figure 2B ).
Pathologic and immunohistochemical assessment of response. (A), Excision specimen of recurrent tumor one year prior to ILI. (B), Tibial biopsy one month after ILI showing no viable tumor. (C), Absence of PD-L1 expression post-ILI and PD-1 inhibition. (D), Brisk CD4+ T cell infiltration in tibial biopsy one month after ILI. (E), Brisk CD8+ T cell infiltration in tibial biopsy one month after ILI. (F), Brisk CD163+ macrophage infiltration in tibial biopsy one month after ILI. Images are presented at 20x magnification.
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f3
Compared to the pathologic appearance of the excision specimen a year prior ( Figure 3A ), a tibial biopsy performed one month after ILI revealed >99% treatment effect ( Figure 3B ). PD-L1 expression was absent in the post-treatment biopsy, with extensive CD4+ and CD8+ T cell infiltrate, as well as CD163+ macrophage infiltrate ( Figures 3C-F ).