CT in End-Stage Sarcoidosis

In a study of CTs in end-stage lung disease defined as the presence of honeycombing, cystic change with well-defined walls, or conglomerate lesions, it was found that when CTs of sarcoidosis were mixed with other cases, a correct diagnosis of sarcoidosis was made in 83% of cases. Three patterns predominated: conglomerate fibrosis with included bronchi (in contrast to silicotic conglomerates, which did not have included bronchi), central cysts of bronchiectasis, and subpleural honeycombing. Characteristic CT features, in order from most to least frequent, are listed below for the 9 cases with sarcoidosis [1].

This slice of left lung from a patient with long-standing sarcoidosis shows some of the changes that correspond to his CTs below. There is fibrous thickening of the fissure and apical pleura.

The ill-defined area of pallor in the mid upper lobe (opposing arrows) represents central fibrosis and conglomeration of airways (see CT below).

Radiating from it to the pleura anteriorly are areas of pericicatricial emphysema (single arrow), which is shown histologically below. The lingula shows more extensive honeycombing.

Subpleural apical bullae can be seen anteriorly. There are scattered thin-walled cysts throughout.

The pale consolidation at the base is caused by his terminal nocardial pneumonia.

Pericicatricial emphysema develops around scar remaining from the granulomas. Honeycombing is distinguished from pericicatricial emphysema by finding fibrotic walls completely surrounding honeycombed spaces. Most of the enlarged spaces in this picture have some portion of the wall that is thin.

 

The major feature here is the bilateral central conglomerate masses consisting of peribronchovascular interstitial and pulmonary fibrosis. Note the perihilar, mass-like, coarse densities surrounding dilated, distorted bronchi, which comprise cicatricial bronchiectasis.

Note the irregular pleural thickening.

Lower lung zones show irregular fibrosis with architectural distortion and associated thin-walled cysts in both central and peripheral lung.

Coronal reformatted images of the entire chest at the level of the tracheal carina, aortic arch, and left atrium nicely show the distribution of calcified lymph nodes in this patient. Adenopathy is primarily located in both hilar, right and left paratracheal, and aorticopulmonary window locations.

This patient also had calcified lymph nodes in more unusual locations such as the subcarinal (see below) and prevascular mediastinum. Calcified nodes were also present throughout the abdomen.

An x-ray of the hilus of one lung shows the irregular calcification of enlarged lymph nodes. (The anterior aspect is toward the left.) The calcifications are probably best described as amorphous, although some might be described as eggshell type. The locations of the pulmonary artery (A) and vein (V) are labeled.

 

Reference:

1. Primack S, Hartman T, Hansell D, Müller N. End-stage lung disease: CT findings in 61 patients. Radiology 1993; 189:681-686.

Clinical summary

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