Pulmonary Manifestations of Systemic Sclerosis and Mixed Connective Tissue Disease.

Systemic sclerosis (SSc) is a rare disease characterized by widespread collagen deposition resulting in fibrosis. Although skin involvement is the most common manifestation and also the one that determines the classification of disease, mortality in SSc is usually a result of respiratory compromise in the form of interstitial lung disease (ILD) or pulmonary hypertension (PH). Clinically significant ILD is seen in up to 40% of patients and PH in up to 20%. Treatment with either cyclophosphamide or mycophenolate has been shown to delay disease progression, whereas rituximab and lung transplantation are reserved for refractory cases.