Diffs > Nodules

Miliary or Small Nodular Pattern

A determination of the distribution of the nodules will aid in refining the differential:

Diffuse (Random) Pattern:

Miliary tuberculosis
Metastatic disease
Synthetic marijuana inhalation {AJR 2015; Berkowitz EA, et al. 204: 750-757

Perilymphatic Pattern:

Sarcoid
Lymphangitic Metastatses
Silicosis

Centrilobular Pattern:

Extrinsic allergic alveolitis (Nodules are ill-defined)
Vascular disorders (Pulmonary edema [look for interstitial thickening], Vasculitis)

Centrilobular with Tree-in-bud Pattern: Small airways disease

Infectious bronchiolitis (Bronchopneumonia, MAC, TB)
Bronchial Disease (Bronchiolitis/ Diffuse panbronchiolitis, Cystic Fibrosis)
Lymphatic disease (Can produce centrilobular densities, but look for interstitial/perilymphatic abnormalities as well)

- Lymphangectic carcinomatosis
- Sarcoid
- Langerhans Cell Histiocytosis