A 65-year-old woman with no medical history visited our hospital with an abnormal chest shadow. Her physical findings were normal including peripheral edema, digital clubbing, cyanosis, or sicca syndrome, and her blood test findings including tumor markers and a respiratory function test were also normal. Her chest CT showed a ground glass nodule with a diameter of 1.5cm in the lower lobe (S6) of the right lung (Fig. 1). Because we suspected lung cancer, a transbronchial lung biopsy (TBLB) was performed: the specimen showed atypical cells with no obvious malignant findings. Three months later, the size of the nodule had increased slightly. For a definitive diagnosis, video-assisted thoracoscopic surgery was performed, and the pathological findings showed diffuse lymphoid follicular hyperplasia, infiltration of the alveolar septum by small lymphocytes and plasma cells, and follicular bronchiolitis (Fig. 2A). There were many lymphoid follicles in the tissue and lymphocyte exudation was present in the alveolar space (Fig. 2B). Immunohistochemically, the follicular area was CD20 positive, and CD3 positive T cells had infiltrated into the alveolar walls (Fig. 3). There was no monoclonal growth of kappa or lambda positive cells. There were a few lymphoepithelial lesions, and lymphocyte infiltration was observed between the bronchiole epithelium. Based on these pathological findings, a LIP pattern was considered. There were no physical or serological findings associated with collagen disease. Seven months after surgery, new localized ground glass shadows appeared (Fig. 4), and they gradually increased on the basal lesion of the lung for four years (Fig. 5). However, because she had no respiratory symptoms and normal respiratory function, she was observed with no medication. In addition, no other underlying diseases associated with LIP developed.
High resolution CT shows a diffuse a ground-glass nodule in the lower lobe of the right lung near the seventh to ninth thoracic vertebrae (arrow).