Small Cell Lung Carcinoma Transformation

**Semantic type:** Finding

**Definition:** A term that usually refers to the histological transformation of EGFR mutation-positive lung non-small cell carcinoma to small cell carcinoma in response to treatment with tyrosine kinase inhibitors, resulting in resistance to first-line tyrosine kinase inhibitors. It may also refer to rare cases of lung adenocarcinoma carrying KRAS G12C mutation that are transformed into small cell carcinoma before treatment.

**Synonyms:** - Lung Adenocarcinoma Transformation - SCLC Transformation