Granulomatous Fibrosing Mediastinitis is a rare complication of Histoplasmosis.
Pathogenesis: idiosyncratic immune response, possibly associated with HLA DQB1*04:02
Clinical features:
(1) fibrous encasement of mediastinal structures
(2) evidence of previous infection with Histoplasmosis (antibodies to Histoplasmosis), typically in someone who has lived in an endemic area
(3) dyspnea
(4) variable intermittent hemoptysis
(5) weight loss, night sweats and/or fever
Histology shows diffuse fibrosis with or without granulomas.
Complications:
(1) stenosis of pulmonary artery
(2) stenosis of major bronchi
(3) superior vena cava syndrome
(4) massive hemoptysis
(5) compression of the esophagus
Differential diagnosis:
(1) IgG4 related fibrosis
(2) malignancy
(3) mycobacterial disease
