The appendiceal tumor is a rare entity; it is usually discovered during appendectomy. This is the case of a 21-year-old man admitted due to abdominal pain accompanied by vomiting, high fever, and weight loss. Paraclinical lab test results: hematocrit, 30.7%; hemoglobin, 10.1g/dl. He is examined by the General Surgery unit, and underwent surgery due to clinical signs of acute appendicitis. The surgical findings are granulomatous lesions, and congestive appendix with tumor. The biopsy performed reveals the presence of malignant epithelial neoplasm consistent with adenocarcinoma. He is eventually discharged from the hospital with good prognosis.