A 0.5 cm elevation is observed in the descending portion of the duodenum, with a smooth surface.

Under normal circumstances, a 0.5 cm smooth-surfaced protrusion in the descending part of the duodenum may be caused by factors such as duodenal papilla, duodenal ulcer, duodenal polyps, duodenal leiomyoma, or gastrointestinal stromal tumors, and targeted management is required. Specific analyses are as follows:

1. Duodenal Papilla

Due to differences in origin, it may be misdiagnosed as a duodenal protrusion. In most cases, this is a normal physiological structure. Diagnosis should combine endoscopic ultrasound examination for further assistance in accurate identification and effective treatment planning.

2. Duodenal Ulcer

Duodenal ulcers are mostly caused by Helicobacter pylori infection or excessive gastric acid secretion. These factors can irritate the duodenal mucosa, leading to local damage. Long-term inflammatory stimulation may also result in localized protrusions. Symptoms often include abdominal bloating, decreased appetite, acid reflux, and belching. Treatment may include oral medications such as omeprazole enteric-coated capsules, rabeprazole sodium enteric-coated tablets, and colloidal bismuth pectin capsules, taken under medical guidance.

3. Duodenal Polyp

Duodenal polyps usually originate from the mucosal layer or muscularis mucosae and are typically around 1 cm in size. They can often be cured clinically through minimally invasive endoscopic treatment.

4. Duodenal Leiomyoma

Duodenal leiomyoma is a tumor arising from the muscularis mucosae of the duodenum, associated with poor dietary habits or chronic inflammation. It can lead to local tumor-like growths and symptoms such as gastrointestinal bleeding and abdominal masses. Treatment options include myomectomy under endoscopy or bowel resection surgery.

5. Gastrointestinal Stromal Tumor (GIST)

Gastrointestinal stromal tumors are soft tissue sarcomas originating from Cajal interstitial cells and can occur anywhere in the digestive tract, most commonly in the stomach and small intestine. The duodenum, being the most fixed portion of the small intestine, if affected by a sarcoma, may present as a mucosal protrusion in the descending duodenum. Treatment may involve surgery and targeted therapy as directed by a physician.

If a patient has a duodenal protrusion, timely medical evaluation is essential to establish an accurate diagnosis and receive appropriate medication and treatment under medical supervision.