Aggressive adenocarcinoma of the lung consisting solely of discohesive cells

A 60-year-old Japanese man was found to have diffuse pneumonia-like shadow in the left S(10) segment on chest computed tomographic scan. Transbronchial lung biopsy yielded a pathological diagnosis of poorly differentiated adenocarcinoma; subsequently, left lower lobectomy was performed. Histopathological analysis showed that the tumor consisted solely of discohesive cells with involvement of the hilar and mediastinal lymph nodes. The immunohistochemical expression of E-cadherin and β-catenin was low, whereas that of p53 was high in the tumor cells. Here, we describe a rare lung adenocarcinoma with discohesive cells, which are considered to indicate high tumor aggressiveness.