Correct!
4. Arteriovenous malformation
While the appearance of the mass on the chest radiograph is ultimately fairly non-specific, the least likely possibility among the considerations above is arteriovenous malformation [AVM]. Typically, AVMs, particularly when they reach the size of the lesion in this patient, are associated with tubular opacities entering and exiting the mass, representing the “feeding” artery[ies] and “draining vein[s], and such opacities are not seen in this case. Primary pulmonary malignancy is certainly a possibility, and the lesion’s location near the chest wall and left major fissure indicate that a lesion arising from the pleura is possible as well. Although pulmonary lymphoma is a rare lesion, the morphology of the mass is consistent with that diagnosis. Hamartoma is possible, although many hamartomas that reach this size often show internal calcification, which is not visible in this lesion. Nevertheless, the appreciation of calcification within a nodule or mass at chest radiography can be difficult, and the lack of visualization of such does not exclude its presence, rendering choice “d” the best answer for this question.
Clinical Course: The patient subsequently underwent thoracic CT (Figures 2A-C) for further characterization of the lesion seen at chest radiography.
Figure 2: Axial and coronal contrast-enhanced thoracic CT in soft tissue windows (Panels A & B) and axial lung window (Panel C) show that the mass is peripherally located in the medial left upper thorax and appears solid. The lesion does not show aggressive features, such as rib destruction. The lung windows show that the lesion has lobulated and irregular borders, but without frank spiculation. The lesion has extensive contact with the chest wall, which can be seen with peripheral lung lesions, but also raises the possibility that the lesion could arise from the pleura or posterior mediastinum.
Click here for a movie of the axial CT scan
Click here for a movie of the coronal CT scan
Regarding the CT appearance of the lesion, which of the following is most accurate?
