CTICasesApical Opacity of Proto (Subclavian Artery Pseudotumor)
Imaging findings
In a patient with a history of irradiated and resected lower extremity sarcoma undergoing screening, chest radiograph shows a faint nodular opacity in the right apex with a fainter mirror-image opacity on the left. CT correlation shows that this opacity corresponds to the normal subclavian/brachiocephalic artery as it courses toward the chest wall, indenting the adjacent lung and producing an ill-defined, fuzzy apical opacity, more pronounced on the right than the left.
Key takeaways
This is the apical opacity of Proto, a normal-anatomy pseudotumor caused by the subclavian or brachiocephalic artery indenting the lung apex near the first rib, originally described by Proto in the plain-film literature of the 1970s-80s before routine CT correlation was available; recognizing this entity, along with Proto's related description of extrapleural fat producing a pseudo-superior-accessory-fissure arc, prevents mistaking normal vascular anatomy for a true apical lung lesion.
AI-assisted summary — may contain errors. Verify against the source video. Learn more
More from this webinar
- Relapsing PolychondritisAutoimmune
- Hepatopulmonary SyndromeVascular
- Pulmonary TuberculosisInfection
- Purpureocillium lilacinum Cavitary Pulmonary InfectionInfection
- Angioinvasive Mucormycosis (Rhizopus) with Aspergillus Co-infectionInfection
- Pembrolizumab-Associated Sarcoid-like ReactionInflammatory
- Fibrotic Hypersensitivity Pneumonitis (Indeterminate for UIP Pattern)ILD
- Amplatzer Amulet Left Atrial Appendage Occlusion DeviceArtifact
See all cases from March 30, 2018 →