Case of the week Details

• Fig 1 (a,b,c,d). Axial HRCT Chest inspiratory images. Bizarre shaped, thin walled, irregular sized clustered cysts, sparing the subpleural parenchyma. Few reticulations noted.
• Fig 2 (a,b,c,d). Coronal HRCT Chest inspiratory images and Fig 3 (a,b) Sagittal HRCT Chest inspiratory images. Bizarre shaped, thin walled, irregular sized clustered cysts, sparing the subpleural parenchyma. Few reticulations noted.

Diagnosis:

Smoking Related Interstitial Fibrosis (SRIF) with combined emphysema.

Discussion:

1. Hallmarks of smoking related interstitial fibrosis (SRIF) with combned emphysema, on HRCT chest are:
   • Thin walled clustered cysts that are bizarre in shape and irregular in size
   • Ground glass opacities
   • Reticulations.
   • Subpleural parenchyma is less involved.
2. As the name suggests, etiology is smoking.
3. It represents a spectrum of changes that occur in smoking related interstitial lung diseases.
4. To D/D from thin walled honeycombing in UIP, SRIF with emphysema has:
   • Thin walled clustered cysts that are irregular in size and bizarre in shape c.f., rounded, uniform layered cysts.
   • Subpleural parenchyma is spared c.f., involves subpleural parenchyma.

References: 

• Otani H, Tanaka T, Murata K, Fukuoka J, Nitta N, Nagatani Y, Sonoda A, Takahashi M. Smoking-related interstitial fibrosis combined with pulmonary emphysema: computed tomography-pathologic correlative study using lobectomy specimens. International journal of chronic obstructive pulmonary disease. 2016;11:1521.

Dr. Deepali Saxena,
DNB, Fellowship Cardiothoracic Imaging (USA)
Lead Cardiac Imaging
Manipal Hospitals Radiology Group.