Abstract
BACKGROUND: Mucosal adenocarcinoma of the descending duodenum is a very rare gastrointestinal tumor. Due to its low incidence, it has rarely been the focus of clinical and pathological studies. The clinical manifestations of these tumors are usually nonspecific, and they are easily misdiagnosed or missed. Pathological diagnosis is the gold standard for diagnosis, but due to the small number of cases, the relevant pathological characteristics and diagnostic criteria are not completely clear. The purpose of this study was to deepen the understanding of the diagnosis and treatment of this disease and to provide a clinical guidance. CASE SUMMARY: A 61-year-old woman who was hospitalized with recurrent abdominal pain for more than 20 days. The patient developed epigastric pain with no obvious cause more than 20 days prior, mainly left epigastric pain and middle epigastric pain, and presented persistent dull pain without nausea or vomiting, fever or chills. The patient was treated at a local hospital, gastroscopy revealed a new lesion in the circum-intestinal cavity in the descending part of the duodenum, and pathological biopsy revealed mucous adenocarcinoma in the descending part of the duodenum. Currently, for further diagnosis and treatment, the patient is admitted to our hospital for surgical treatment for "malignant tumor of the duodenum" in the outpatient department. CONCLUSION: Mucosal adenocarcinoma of the descending duodenum has a high misdiagnosis rate and missed diagnosis rate, clinical manifestations lack specificity, and pathological diagnosis is the main basis for diagnosis.