Case Author(s): Charles Pirngle, M.D., Tom R. Miller, M.D., Ph.D. , 02/13/96 . Rating: #D2, #Q3

Diagnosis: Fibrosing Mediastinitis

Brief history:

Shortness of breath


Posterior ventilation images

View main image(vq) in a separate image viewer

View second image(vq). Lung perfusion images

View third image(xr). PA chest radiograph

View fourth image(ct). Transverse CT image through the mediastinum

Full history/Diagnosis is available below

Diagnosis: Fibrosing Mediastinitis

Full history:

71-year old woman with a right upper lobe infiltrate and a past history of pulmonary embolism. She now has shortness of breath.


20.5 mCi Xe-133 gas by inhalation and 4.1 mCi Tc-99m MAA i.v.


The Xe-133 ventilation images show mildly reduced ventilation in the right upper lobe manifested by decreased single-breath and washin activity with mild retention during washout. The perfusion images show a matching defect involving the entire right upper lobe. Also, according to the report of an outside study from one year earlier, there has been no change in the appearance of the ventilation-perfusion study. The chest radiograph demonstrates narrowing of the distal trachea and also possibly the right mainstem bronchus with streaky opacities in the right upper lobe, suggesting an area of infiltrate or atelectasis. Also, a recent CT scan of the chest demonstrated right hilar adenopathy with coarse calcification and volume loss in the right upper lobe.


Fibrosing mediastinitis is the most likely etiology for the computed tomographic, radiographic, and ventilation-perfusion abnormalities. The most frequent cause of fibrosing mediastinitis is granulomatous disease, with histoplasmosis the likely offender in the Midwest. Tuberculosis and actinomycosis may also result in the same findings. Other causes of fibrosing mediastinitis include autoimmune disease and methysergide. The characteristic scintigraphic findings, present in this case, are decreased to absent perfusion involving a large area of lung with normal or near-normal ventilation.

Major teaching point(s):

It would be unusual for pulmonary embolism to present as a single lobar or whole lung defect. Because PE occur multiply, the single defect suggests other diagnoses.

Differential Diagnosis List

In addition to fibrosing mediastinitis, the possibilities include a central obstructing mass, such as bronchogenic carcinoma, Swire-James syndrome, and, unlikely, embolus to the upper lobe pulmonary artery.

ACR Codes and Keywords:

References and General Discussion of Ventilation Perfusion Scintigraphy (Anatomic field:Lung, Mediastinum, and Pleura, Category:Inflammation,Infection)

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Case number: vq017

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