Barrett esophagus

A 69-year-old man presents to the primary care physician with dysphagia. The patient reports progressive difficulty swallowing, now to the point where he has trouble tolerating liquids and sometimes vomits after eating. The patient has a significant history of alcohol abuse, 50-pack-year smoking history, as well as hypertension and hyperlipidemia. Temperature is 37°C (98.6°F), pulse is 68/min, respirations are 14/min and blood pressure is 130/82 mmHg. Physical exam shows a thin male with bitemporal wasting and non-tender anterior cervical lymphadenopathy. Oral and neck examination is unremarkable aside from poor dentition. Laboratory results are as follows:  
 

Laboratory value	Result
CBC, Serum
Hemoglobin	11.2  g/dL
Hematocrit	33.6%
Leukocyte count	10,100 /mm3
Platelet count	149,000/mm3
MCV	72 fL
RDW	11.5-14.5%
Iron Studies, Serum
Serum Iron	90 μg/dL
Ferritin	Ferritin 170 ng/mL
Total iron binding capacity	220 μg/dL

A barium swallow study reveals an esophageal mass that significantly narrows the lumen in the middle of the esophagus. Which of the following pathologic features is most likely to be found on upper endoscopy?