Fig. 3.

Histological and imaging findings in Case 3.

(A) Hematoxylin and Eosin staining of biopsy specimens. The patient was diagnosed with adenocarcinoma based on the evaluation of the initial biopsy specimen. Bar indicates 100 μm. (B and C) At 32 months after the initial diagnosis (8 months after the final dose of EGFR-TKI), the patient's liver metastases rapidly progressed in 2 months. (D–I) Autopsy findings from metastatic colonies in the adrenal gland, brain, and liver. The tumor cells in the adrenal gland, which showed relatively stable disease activity, were well differentiated and negative for INSM1. On the other hand, the tumor cells in the brain and liver, which showed aggressive disease activity, were poorly differentiated with a high N/C ratio and were positive for INSM1, leading to a diagnosis of SCLC transformation. Bar indicates 200 μm.