Appendiceal malignancies are rare clinic entities. The clinical presentation of appendiceal malignancies is often atypical. Acute abdominal pain and acute appendicitis, which requires early surgical intervention, are the most common clinical presentations of appendiceal malignancies. In this case report, an adenocarcinoma of the appendix in a 64-year-old male from a nursing home has been presented. He had right lower quadrant pain for the last 5 days. On physical examination, he had significant guarding. Intravenous contrast-enhanced abdominopelvic tomography revealed no pathological features. Laparotomy under general anesthesia was scheduled. During exploration, a perforated appendicitis was observed. Formal appendectomy was performed. The patient was lost due to pneumonia and septic shock 5 days after surgical intervention. In addition, the natural history of the disease and its basic diagnostic and therapeutic aspects are discussed. Preoperative or intraoperative diagnosis may not be available for some patients. Thus, routine histopathological examination is essential for adequate diagnosis and treatment.