PMC6176787_01
Pathological findings (A) The first biopsy sample revealed adenocarcinoma in the left lower lobe of the primary lesion (hematoxylin and eosin staining x400). (B) The second biopsy sample revealed small cell lung cancer in the left lower lobe of the primary lesion (hematoxylin and eosin staining x400). (C, D) Immuno histopathological analysis showed positive staining for chromogranin (C) and synaptophysin (D) in the second biopsy sample (x400).
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We subsequently performed re-biopsy of the primary tumor in October 2016 and found both an adenocarcinoma harboring an EGFR exon 19 deletion without EGFR-T790M mutation and an SCLC component that showed positive staining for chromogranin and synaptophysin in the biopsy specimens (Fig. 1).
Clinical course of the sequential treatment and tumor markers for EGFR-mutated NSCLC. An alternating therapy is composed of erlotinib and systemic chemotherapy, combined therapy with pemetrexed plus bevacizumab. Bx., biopsy; 19 del, exon 19 deletion in EGFR; T790M, EGFR-T790M mutation.
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The patient received the third-generation EGFR-TKI osimertinib (80 mg/day) from July 2017 and maintained a clinical response for 10 months (Fig. 2).