Symmetric hilar and right paratracheal nodes with PERILYMPHATIC nodules (along fissures, subpleural surfaces and bronchovascular bundles) in the upper and mid zones — and, late, upper-lobe fibrosis pulling the hila up and back.
Orient first
- Sarcoid granulomas follow the lymphatics, so the nodules sit on fissures, the pleura and bronchovascular bundles — the perilymphatic pattern.
- Radiographic (Scadding) stages 0–IV describe nodes, nodes + lung, lung alone and fibrosis; they are descriptive, not a clinical sequence.
- It is a diagnosis of exclusion: tuberculosis, lymphangitic carcinomatosis, silicosis and lymphoma can look similar.
Acquire the study
- PA chest radiograph; thin-section CT (non-contrast HRCT for the lungs; contrast when nodes need assessment); expiratory images if air trapping is suspected.
The manoeuvre
- Nodes: bilateral symmetric hilar plus right paratracheal (Garland triad); calcification may be amorphous or eggshell in chronic disease.
- Nodules: perilymphatic micronodules — beaded fissures, subpleural and peribronchovascular; upper and mid zone predominant.
- Conglomerate masses and the galaxy sign (a mass made of coalescent micronodules).
- Fibrosis: upper-lobe volume loss, posterior displacement of the main and upper-lobe bronchi, traction bronchiectasis; look for aspergilloma in fibrotic cavities.
- Assign the radiographic stage and describe activity (nodules, ground glass) versus fibrosis.
What confirms it
- Symmetric hilar/mediastinal nodes with perilymphatic upper-zone nodules in a compatible setting, with tissue (non-necrotising granulomas) and alternatives excluded.
What licenses you to exclude it
- A normal CT with no nodes or perilymphatic nodules makes thoracic sarcoidosis very unlikely.
The classic misread
- Calling asymmetric, necrotic nodes sarcoid — think tuberculosis or lymphoma.
- Calling smooth or nodular interlobular septal thickening with effusion sarcoid — think lymphangitic carcinomatosis.