000 Desquamative Interstitial Pneumonia, DIP

Position of Disease
Lower Lobe distribution
Ashley Davidoff MD TheCommonvein.net lungs-0771

 

aka alveolar macrophage pneumonia
a less angr brother to RB ILD

  • Inflammatory
    • pigmented intra-alveolar macrophages and giant sells in the alveioli
  • Cause
    • Mostly smokers
      • 10-40% are non smokers
        • inhalational toxic
        • druga
        • viral illness
        • autoimmune diseases
  • results
    • Structural
      • Path
        • alveoli
          • architecture maintained
          • macrophages
            • uniform diffuse
        • Interstitium
          • mild chronic inflammation
      • CXR
        • usually normal
      • CT
        • widespread
        • patchy ground glass
          • diffuse less common
        • lower lobes (70%)
          • bilateral
          • relatively symmetrical
          • peripheral (60%)
          • honeycomb can happen
    • Functional
      • LFT mild impairment

Buzz

  • DIP
    • aberrances
      • DIP imagine somebody dipping a rag of into cigarette  smoke and dabbing it in the lower lung zones smoke

Lungs

  • Desquamative –
    • squams = misnomer
    •  infiltrates represent alveolar filling with pigmented macrophages. alveoli

 

interstitial mucosa/submucosa vessels

pneumonia = “inflammation of the lungs,”

desquamate – fill the alveoli

Small Airways

Inflammation

Secondary Lobule

Alveoli

Inhalation – Lower Lobes

Smokers but

  • Desquamative Interstitial Pneumonia (DIP) is a rare form of idiopathic interstitial pneumonia (IIP).
  • Cause
    • Smokers
      • also related to marijuana smoke inhalation,
    • infections such as HIV,
    • toxins, or
    • occupational exposure (eg, to asbestos)
  • Results in
    •  infiltrates represent alveolar filling with pigmented macrophages. alveoli
  • Diagnosis
    • Clinical
      • Cougn Dyspnea
      • DX difficult on
        • clinical and radiological features alone
        • requires a (surgical) lung biopsy
    • Imaging
      • bilateral ground-glass opacities with
      • lower lobe predominance (92%).
      •  irregular reticulation,
      • traction bronchiectasis and
      • cysts.
      • sometimes
        •  ground-glass opacities
        • architectural distortion,
        • traction bronchiectasis and
        • honeycombing.
  • Path
    • pigmented macrophages within
    • most of the distal airspace of the lung
  • Histologically,
    • DIP is similar to RB-ILD,
      •  DIP and  RB-ILD are a spectrum
      • differing in compartments involved
      • DIP not bronchiolocentric.
      • hyperplasia of the alveolar type II cells
      • distribution pattern more homogeneous a
      • mild peribronchial fibrosis
Photomicrograph of a surgical lung biopsy specimen shows widespread intraalveolar accumulation of pigmented macrophages (arrows).
Anil K Smoking related ILD Radiographics
DIP
Noted are elevated numbers of macrophages within the alveoli of the lung. The alveolar macrophages have a characteristic light brown pigmentation and accumulate in the alveolar lumen and septa regions of the lower lobes of the lungs. The typical effects of the macrophage accumulation are inflammation and later fibrosis with stiffness of the lung
Courtesy Wiki
web lungs 436
Typical example of high-resolution computed tomography (HRCT) findings in desquamative interstitial pneumonia (DIP). Coronal a) and axial b) computed tomography (CT) slices show bilateral basal and peripheral ground-glass opacity. Some superimposed fine linear opacities are also seen, especially on the left side (coronal slice a)), corresponding with thickened inter- and intralobular septa.
Hellemons M etal Eur Respir Rev 2020; 29: 190181. – September 30, 2020
Progression of DIP and pulmonary fibrosis in a 55-year-old male smoker. (A) Axial CT image through the lower lobes from 2012 shows lower lobe predominant ground glass opacity with scattered cystic changes. In addition, there is mild reticulation (black arrows) and bronchiectasis (white arrows), signifying underlying fibrosis. Open lung biopsy showed DIP and a NSIP of fibrosis. (B) Axial CT image from 2015 at the same level as the scan obtained in 2013 shows progressive fibrosis with worsening reticulation (black arrows) and bronchiectasis (white arrows). Explant showed DIP combined with severely fibrotic NSIP.
Kligerman S et al Clinical-Radiologic-Pathologic Correlation of Smoking-Related Diffuse Parenchymal Lung Disease 2016
Desquamative interstitial pneumonitis. (a) Axial and (b) coronal lung window CT scans in a 64-year-old man with a history of smoking (17 pack-years) and shortness of breath. Images show small cysts in both lower lobes (arrow) with surrounding interstitial prominence.
Parekh, M et al Review of the Chest CT Differential Diagnosis of Ground-Glass Opacities in the COVID Era Radiology Vol. 297, No. 3 July 2020

 

Radiology Buzz

The Secondary Lobule
The arteriole and bronchiole lie in the center of the lobule.
Pulmonary venules (red) and lymphatics (yellow). lie in the periphery of the lobule
42440b03
Davidoff Art Courtesy Ashley Davidoff MD

References and Links

Attili, A.K etal  Smoking-related Interstitial Lung Disease: Radiologic-Clinical-Pathologic Correlation RadioGraphics Vol. 28, No. 5

Gupta et al Diffuse Cystic Lung Disease: Part I  American Journal of Respiratory and Critical Care Medicine 191(12)  April 2015

INTERSTITIAL PNEUMONIA , IP