Lymphocytic Interstitial Pneumonitis
Definition
- Chronic lung disease characterized by interstitial lymphocytic infiltration
Alternate/Historical Names
- LIP
- Lymphocytic interstitial pneumonia
Diagnostic Criteria
- Clinical
- Gradual onset of dyspnea, cough
- Most have symptoms >6 months
- May occur at any age
- Frequently associated with immune related diseases
- Autoimmune diseases including collagen vascular
- Immunodeficiency including AIDS and common variable immunodeficiency
- Multicentric Castleman disease
- Drug reactions
- 80% have polyclonal gammopathy
- 33-50% 5 year mortality
- Gradual onset of dyspnea, cough
- High resolution computed tomography (HRCT)
- Ground glass opacities
- Perivascular cysts
- Perivascular honeycombing in late stages
- Histopathologic features
- Diffuse cellular expansion of interlobular and alveolar septa
- Does not preferentially track along lymphatic routes (bronchovascular bundles)
- Polymorphous infiltrate of lymphocytes, plasma cells and macrophages
- Small and large lymphocytes, mostly T cells
- Germinal centers may be seen in some cases along bronchovascular bundles
- Lymphocytes and plasma cells are polyclonal
- Histiocytes may be multinucleated or epithelioid
- May progress to interstitial fibrosis and honeycomb change
- Diffuse cellular expansion of interlobular and alveolar septa
Gerald J Berry MD
Robert V Rouse MD
Department of Pathology
Stanford University School of Medicine
Stanford CA 94305-5342