3.  An esophageal biopsy from a 25-year-old man with retrosternal pain shows the histopathologic changes in this picture. This form of esophagitis is due to:

  4.  A histologic change that definitively supports a diagnosis of Barrett esophagus within an esophageal biopsy is:

  5.  An esophageal biopsy is taken from a patient with history of GERD. The most significant histopathologic changes are shown in this photomicrograph. Which of the following diagnostic categories is most appropriate to this case?

  6.  An esophageal biopsy is taken from a patient with history of GERD. The most significant histopathologic changes are shown in this photomicrograph. Which of the following diagnostic categories is most appropriate to this case?

  7.  The histopathologic changes seen in this esophageal biopsy from a patient with Barrett esophagus are most consistent with:

  8.  Superficial squamous cell carcinoma of the esophagus is defined by:

  9.  A 54-year-old man presents with dysphagia. Endoscopy reveals a large fungating mass in the middle third of the esophagus. This photomicrograph shows its histologic appearance. Which of the following is the most likely diagnosis?