Cancer versus not cancer on esophagram. [Gastrointestinal] [FL]

Quick one today. Take a look at Patient A and Patient B.

Patient A has a smooth focal indentation of the posterior cervical esophagus.

Patient B has a broader indentation that is also irregular and nodular along its contour.

Patient A has a cricopharyngeal bar, which is a prominence caused by the cricopharyngeus muscle that can cause dysphagia if it gets really prominent. Patient B has esophageal squamous cell carcinoma.