Pulmonary Nodule as a Manifestation of IgG4-Related Disease

Abstract

IgG4-related disease is a systemic fibroinflammatory condition that can affect virtually all organs and systems of the human body, most frequently involving the pancreas. We describe the case of a 76-year-old man under follow-up for idiopathic pulmonary fibrosis who, during routine follow-up examinations, was found to have a growing nodule in the apical segment of the right upper lobe. He underwent a transthoracic biopsy in order to exclude pulmonary neoplasia. Histopathological analysis revealed areas of fibrosis and inflammatory infiltrate composed of lymphocytes and IgG4-positive plasma cells, with an IgG4/IgG ratio greater than 40%, findings consistent with IgG4-related lung disease.