ALK-rearranged squamous cell carcinoma of the lung.

The fusion gene echinoderm microtubule-associated protein-like 4 (EML4)-anaplastic lymphoma kinase (ALK) is identified in approximately 5% of non-small-cell lung cancer patients. A rare case of ALK-positive squamous cell carcinoma of the lung is reported. A 60-year-old man, an ex-smoker with a 720-packs-per-year tobacco smoking history, presented with a mass lesion in the upper lobe of the left lung on chest computed tomography. Transbronchial biopsy of the mass confirmed a diagnosis of lung squamous cell carcinoma, and it was proven to have ALK rearrangement by fluorescent in situ hybridization. The patient underwent left upper lobectomy. Hematoxylin and eosin staining of the surgical specimen demonstrated the typical morphology of pure squamous cell carcinoma. The patient has been advised to attend regular check-ups for postoperative recurrence. ALK testing and subsequent ALK-targeted treatment can be a possible option in cases of postoperative recurrence.