PMC6468187_01
Chest CT of primary lesion and mediastinal lymph node findings. A: Pretreatment primary tumor. B: Primary tumor after four months from EGFR-TKI treatment started. C: Regrowth primary tumor after EGFR-TKI treatment. D: Primary tumor after two months from chemotherapy (CDDP+CPT-11) started.
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Right hilar invasive lesion and multiple mediastinal and cervical lymphadenopathy revealed by Computed tomography (Fig. 1A). His best tumor response was assessed partial response (Fig. 1B), and both tumor markers were reduced after treatment started (Fig. 3). Recurrence of primary lesion was revealed in chest CT without recurrence of mediastinal lymph nodes, although serum CEA level stayed in the normal range (Fig. 1C). Best response of standard chemotherapy was assessed partial response (Fig. 1D).
Pathological findings at biopsy specimen. A: Pretreatment tumor (Hematoxylin and eosin stain) B: Pretreatment tumor (Synaptophysin) C: Pretreatment tumor (Chromogranin A) D: Rebiopsy tumor after EGFR-TKI treatment (Hematoxylin and eosin stain) E: Rebiopsy tumor after EGFR-TKI treatment (Synaptphysin) F: Rebiopsy tumor after EGFR-TKI treatment (Chromogranin A).
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On the contrary, CD56, synaptophysin, and chromogranin A which known for neuroendocrine marker were negative at biopsy sample (Fig. 2A, B, C). Malignant small cells with high nuclear cytoplasmic ratio were observed in the biopsy sample, and synaptophysin and chromogranin A were positive in the cells (Fig. 2D, E, F).