Background: Small bowel adenocarcinoma is a rare malignant tumor, with the typical age of diagnosis being 60 years old. In the field of risk factors, we can distinguish, between genetic disorders, inflammatory bowel diseases, smoking, and alcohol abuse. Guidelines for the screening methods are very wide, hence it may be difficult to make the right diagnosis at the early stages of cancer. Additional difficulties can be caused by similarities to inflammatory processes in the gastrointestinal tract. Case report: We present a case of a 22-year-old male patient, with the symptoms of weight loss, stool retention, abdominal pain, and vomiting. The patient was initially misdiagnosed with inflammatory bowel disease and received the first dose of anti-inflammatory treatment. At that point, the diagnostic process and the workflow of medical care were delayed due to the COVID-19 pandemic. After receiving the x-ray and computed tomography, the obstruction of the ileum was found, and an urgent operation was performed. Tissue samples obtained during surgery revealed the proper diagnosis, a low-differentiated adenocarcinoma (G3) of the small intestine, stage T4Nx. Conclusion: Taking into consideration the patient’s condition, age, and symptoms, we should always think about the probable malignant process. Inflammatory diseases are known for increasing cancer risk and should always be the indication of this disease. The age of onset of the disease is very unusual, however, we must be aware of such cases in our clinical practice. Keywords: Small bowel adenocarcinoma; ileus; covid-19