Anaplastic lymphoma kinase-positive squamous cell carcinoma of the lung: A case report.

It is widely known that echinoderm microtubule-associated protein-like 4 anaplastic lymphoma kinase (EML4-ALK) rearrangement mostly occurs in the adenocarcinoma subtype of non-small-cell lung cancer (NSCLC). Patients with squamous cell carcinoma harboring the ALK rearrangement are extremely rare. This is a case report of a squamous cell carcinoma patient with EML4-ALK rearrangement. An elderly man with a heavy smoking history presented with a mass lesion in the right main bronchus. Bronchoscopic biopsy of the tumor confirmed a diagnosis of squamous cell carcinoma, and it was proven to harbor ALK rearrangement, based on fluorescence in situ hybridization, but not epidermal growth factor receptor mutations. The patient underwent radiation therapy, with a markedly favorable response. ALK-targeted treatment may be a viable option if disease progression occurs in such a case in the future.