Ground-glass nodule in a patient with echinoderm microtubule-associated protein-like 4-anaplastic lymphoma kinase (EML4-ALK)-positive lung cancer: a case report

BACKGROUND Grand-glass nodule for CT image has thought to be less aggressive tumor in lung cancer. Echinoderm microtubule-associated protein-like 4-anaplastic lymphoma kinase (EML4-ALK)-positive lung cancer presenting with Ground-glass nodules (GGNs) is relatively rare, and few such cases have been reported. CASE PRESENTATION An asymptomatic 56-year-old woman exhibited a 1.1-cm GGN in the lower lobe of the left lung on computed tomography during a medical checkup. Positron emission tomography showed no difference in uptake by the nodule compared with other organs. We elected to perform surgery because the nodule included a solid component and had grown only slightly during the last 2 years according to thin-section computed tomography. Partial resection of the lower left lung was performed by video-assisted thoracic surgery. Pathological examination revealed mucus-producing high columnar epithelium forming an irregular tubular-acinar-like structure partly replacing the alveolar epithelium on hematoxylin and eosin staining. More than 50 % of the tumor demonstrated a lepidic growth pattern. The tumor was negative for epidermal growth factor receptor mutation but positive for the EML4-ALK fusion oncogene according to fluorescence in situ hybridization. CONCLUSIONS We herein report a case of EML4-ALK-positive lung cancer presenting with a GGN along with a review of the relevant literature, including histopathological findings and imaging features. We consider that EML4-ALK-positive lung cancer is often highly progressive and that careful follow-up is therefore essential in these patients.