PMC6586950_01
HRCT images on the first visit revealed a 28-mm tumor in the left lower lobe (A). The tumor's long axis increased to 40 mm 21 days later (B). The tumor's long axis increased to 57 mm 24 days later (2 days after the initiation of pembrolizumab) (C). The tumor's long axis increased to 80 mm 43 days later (21 days after the initiation of pembrolizumab) (D). A large amount of bloody pleural effusion appeared 56 days later (34 days after initiation of pembrolizumab) (E, F).
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High resolution computed tomography (HRCT) revealed a 28 mm mass shadow in the left lower lobe and enlargement of left hilar, mediastinal, and right subclavian lymph nodes (Fig. 1A). The tumor shadow was 40 mm in the largest diameter on chest HRCT performed on the day before pembrolizumab treatment (Fig. 1B). On chest HRCT, the primary tumor shadow increased in size to 57 mm, with growing of ground glass shadows (Fig. 1C). The ground glass shadow around the tumor improved, but the primary tumor increased in size to 80 mm on chest HRCT on day 21 after pembrolizumab administration (Fig. 1D). After the unexpected appearance of significant bloody pleural effusion (Fig. 1E and F), the patient died on day 37 after pembrolizumab administration.
Assessment of the subcarinal lymph node specimen by EBUS-TBNA (A) revealed that the PD-L1 expression rate was 98% before pembrolizumab administration (B) and less than 1% in the autopsy (C). The PD-L1 expression rate was different in the portions of the primary lung cancer at autopsy; the highest rate was 10% (D) and the lowest rate was less than 1% (E). The overall primary tumor expression rate was approximately 1% based on autopsy results. Original magnification: (A), (B), (D), (E) x200, (C) x100. Hematoxylin and eosin staining (A). PD-L1 expression was measured using a prototype immunohistochemistry assay with an anti-PD-L1 22C3 antibody (B)-(E).
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Immunohistochemical expression of PD-L1 in the EBUS-TBNA biopsy was 98% (Fig. 2A and B). We compared the PD-L1 expression rate of the cancer tissue in the subcarinal lymph node, taken by EBUS-TBNA biopsy (Fig. 2A), to the identical lymph node taken at autopsy. It was 98% in the EBUS-TBNA (Fig. 2B) and less than 1% in the autopsy (Fig. 2C). The PD-L1 expression rate was different in the portions of the primary lung cancer at autopsy, with the highest rate at 10% (Fig. 2D) and the lowest <1% (Fig. 2E).