Progressive massive fibrosis

Progressive massive fibrosis (PMF) refers to the formation of large mass-like conglomerates, predominantly in the upper pulmonary lobes, associated with radiating strands. These classically develop in the context of certain pneumoconioses (especially Coal worker's pneumoconiosis and silicosis) although similar mass-like densities have occasionally been described with talcosis.

Radiographic features


Are seen are mass-like areas of lung opacification associated with radiating strands, the "sausage-shaped" mass is characteristic. These regions can commonly contain air bronchograms and calcifications 4. These areas can shrink over time or move towards the hilar regions 5.


Magnetic resonance imaging can be helpful for distinguishing between progressive massive fibrosis and lung cancer 3. Lung cancer typically appears as T2 bright, whereas PMF appears as T2 dark (compared to skeletal muscle)3.

The most frequent MRI appearance are regions which have following signal characteristics 1-2:

  • T1: iso hyper-intensity
  • T2: hypointensity (when compared with skeletal muscle); areas of internal high T2 signal either rim enhancement or no enhancement may also be seen
Nuclear medicine

On PET-CT, PMF can be FDG-avid 3.

Differential diagnosis

Possible differential considerations include:

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Article information

rID: 20929
System: Chest
Tag: cases
Synonyms or Alternate Spellings:
  • PMF
  • Progressive massive fibrosis (PMF)

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Cases and figures

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    Case 1: with silicosis
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    Case 2: with silicosis
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    Partially calcifi...
    Case 3
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    Case 4
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    Case 5: with silicosis
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    Case 6
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    Case 7
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    Axial stack of th...
    Case 8
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