CONCLUSIONS: This is the first reported case of coexisting pulmonary adenocarcinoma and atypical carcinoid tumor with an ALK fusion only detected in the carcinoid component. The presence of ALK rearrangement in pulmonary carcinoid tumor is very uncommon, and there is currently no standard treatment for advanced stages. Therefore, comprehensive molecular testing, including ALK rearrangement analysis, should be recommended for mixed tumors exhibiting features of atypical carcinoid. ALK …