Lung adenocarcinoma associated with IgG4-related respiratory disease

Abstract

A 79-year-old man was found to have an abnormal shadow on chest computed tomography (CT) during follow-up of IgG4-related disease (IgG4-RD). A 30-mm ground-glass opacity nodule in segment 2 of the right lung was observed, which showed an increase over time, bronchoscopy was performed, and the nodule was diagnosed as adenocarcinoma by biopsy. The nodule showed positive uptake (SUVmax 2.0) upon FDG-positron-emission-tomography (PET). He underwent a right upper lobectomy and lymph node dissection by video-assisted thoracic surgery. The histopathological diagnosis was pT2aN0M0, stage IB, and in the background lung, marked fibrosis and infiltration of lymphocytes and plasma cells were observed, and IgG4-positive plasma cells were also confirmed. The background lung was diagnosed with IgG4-related respiratory disease (IgG4-RRD). The tumor also showed infiltration of plasma cells and IgG4-positive plasma. Postoperative adjuvant chemotherapy was not performed, but the patient has been alive for a year and a half without recurrence.