pathology is inconclusive, what is next?

A 63-year-old man presented with chronic abdominal pain of 2 months duration and was referred for upper GI endoscopy. The patient’s pain is diffuse and persistent and has not been referred to other sites with a severity of 7/10, according to the pain scale. The pain is associated with nausea and anorexia and prevents the patient from eating. The patient’s pain is not relieved with simple analgesics and antispasmodics. A computed tomography scan revealed mural thickening of the gastric pylorus and small bowel loops measuring 13 mm in maximum thickness with minimal ascites. The history is remarkable for an attack of shoulder and back pain 20 years ago that was treated with nonsteroidal anti-inflammatory drugs that affected the stomach and led to epigastric pain managed with PPIs. Clinical examination is remarkable for abdominal tenderness and generalized skin vitiligo. The patient underwent an upper digestive #endoscopy. The scope revealed inflammation in the pyloric region, duodenum, and lower esophagu