
Dear Friends,
Dr. Manel Martínez, a long-time friend of the Muppet, has provided the following case: an asymptomatic 67-year-old man in whom a mass was discovered in the chest radiographs.
Diagnosis:
1. Aortic aneurysm
2. Hydatic cyst of lung
3. Left pulmonary artery aneurysm
4. None of the above

PA chest, asymptomatic 67-year-old man

lateral chest, asymptomatic 67-year-old man
Click here for the answer to case #56
Findings: chest radiographs show a middle mediastinal mass, with visible peripheral lineal calcification in the PA view (arrows).

Fig. 1
According to the wise words of Dr. Pepe, a mass with this type of calcification is either a cyst or a vascular lesion. Hydatic cysts of the lung do not calcify. They may calcify when in the mediastinum, as well as congenital duplication cysts, but both are uncommon. Aneurysms of pulmonary artery are very unusual and the normal contour of left pulmonary artery (black arrows) excludes this possibility. The most likely diagnosis is saccular aneurysm of descending aorta, confirmed with enhanced CT (Fig. 2, arrows)

Fig. 2
Final diagnosis: saccular aneurysm of descending aorta.
Teaching point: when seeing lineal peripheral calcification, think of cyst vs. vascular (Dr. Pepe dixit).