Case report: ALK inhibitor-induced transformation of ALK fusion-positive lung adenocarcinoma to large cell neuroendocrine carcinoma

The transformation of lung adenocarcinoma into large cell neuroendocrine carcinoma (LCNEC) in terms of genotype and histology has been described as a mechanism of acquired resistance to epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI). However, this phenomenon is exceedingly rare in anaplastic lymphoma kinase (ALK)-positive lung adenocarcinoma. Here, we report a case of an ALK-positive lung adenocarcinoma patient who developed resistance following sequential treatment with the ALK-TKI alectinib and lorlatinib, accompanied by histological transformation to LCNEC and concurrent genetic alterations including TP53 deletion, CDKN2A deletion, and MYC amplification. This case expands the spectrum of ALK-TKI resistance mechanisms and highlights the potential value of exploring combinatorial approaches incorporating immunotherapy, antiangiogenic therapy, and chemotherapy for the management of such cases.