Human pathology

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lymphoid interstitial pneumonia

LIP, lymphocytic interstitial pneumonitis, lymphoid interstitial pneumonitis

Definition: LIP is a form of ?idiopathic? interstitial pneumonia.

Synopsis

- dense and diffuse alveolar septal infiltrates associating lymphocytes, plasmocytes, plasmacytoid cells and macrophages
- +/- multinucleated giant cells
- +/- small ill-defined epithelioid granuloma
- +/- interstitial fibrosis
- +/- microscopic honeycomb remodeling
- +/- BALT hyperplasia (pulmonary lymphoid hyperplasia)

Associations

- pulmonary infections

  • Pneumocystis jiroveci pneumonia
  • Epstein-Barr virus infection
  • HIV infection
  • Legionella pneumonia
  • tuberculosis
  • Mycoplasma
  • Chlamydia

- hypersensitivity pneumonitis (extrinsic allergic alveolitis)

- dysimmunity and auto-immunity (39%)

- immunodeficiency diseases (14%)

  • HIV infection +/- DILS
  • genetic immunodeficiency syndromes
    • common variable immunodeficiency (CVID) (10607809)
    • agammaglobulinemia

- allogenic bone marrow transplantation (pulmonary GVHD)
- drug reactions
- pulmonary alveolar microlithiasis

Differential diagnosis

- NSIP
- low-grade lymproliferative disease
- hypersensitivity pneumonitis
- atypical mycobacterial infections
- pulmonary drug reactions

See also

- other pulmonary lymphoid hyperplasias

- lymphoid pneumonitis

References

- Swigris JJ, Berry GJ, Raffin TA, Kuschner WG. Lymphoid interstitial pneumonia: a narrative review. Chest. 2002 Dec;122(6):2150-64. PMID: 12475860