Anaplastic Lymphoma Kinase (ALK) Rearrangement-positive Lung Cancer with Transformation to Pleomorphic Carcinoma.

A 55-year-old woman was diagnosed with a tyrosine kinase inhibitor of anaplastic lymphoma kinase (ALK) rearrangement-positive lung adenocarcinoma and treated with chemotherapy consisting of crizotinib, a tyrosine kinase inhibitor of ALK, as second-line chemotherapy. However, the size of the metastatic adrenal lesion increased, and the patient died due to multiple organ failure. An autopsy report revealed that the metastatic lesion of the adrenal tumor was ALK rearrangement-positive pleomorphic carcinoma. The epithelial-mesenchymal transition (EMT) marker vimentin was immunohistochemically positive in both the lung and adrenal lesions. The present case report suggests the possibility of transformation into pleomorphic carcinoma as a result of EMT in patients with ALK rearrangement-positive lung cancer.