Chronic pleuritis associated with IGG4 related disease

Abstract

IgG4-related disease (IgG4-RD) is an uncommon multisystemic entity, characterized by lesions with a
dense lymphoplasmacytic infiltrate with abundant immunoglobulin G (IgG) 4-positive cells, storiform
fibrosis, obliterative phlebitis, and elevated level of serum IgG4. Thoracic involvement may affect the
lungs, airways, mediastinum, and pleura and is observed in approximately 40% of the patients. We describe
the case of a 66-year-old male patient with multiple comorbidities and a history of recurrent pleural
effusion. Pleural biopsy revealed chronic pleuritis with obliterative phlebitis and a dense
lymphoplasmacytic infiltrate. Immunostaining revealed: ≥40 IgG4+ cells/high power field and the
IgG4+:IgG+ ratio is >50 %. Plasma dosage of IgG subclasses revealed elevated levels of IgG4. Treatment
with methylprednisolone pulses was started for three days, with which a favorable response was obtained,
without relapses in subsequent controls. The importance of considering this pathology within the
differential diagnoses in patients with pleural effusion is highlighted, owing its generally favorable response
to corticosteroids and potential irreversible sequels a delayed treatment may impose.