Appendiceal Adenocarcinoma Masquerading as a Chronic Intra-abdominal Abscess.

Appendiceal adenocarcinoma is a rare gastrointestinal malignancy that often presents with nonspecific symptoms and is frequently misdiagnosed as acute or chronic appendicitis. This condition is often characterized by chronic lower right quadrant abdominal pain, bloating, changes in bowel habits, and weight loss. Diagnostic delay is common, particularly in patients managed conservatively or those with comorbid conditions that obscure abdominal symptomatology. We present a case of appendiceal adenocarcinoma discovered following recurrent appendicitis complicated by chronic intra-abdominal abscess in an 81-year-old man with autosomal dominant polycystic kidney disease (PCKD). Given the patient's age and comorbidities, palliative care was pursued. This case highlights the diagnostic challenges of appendiceal malignancy, particularly in patients with recurrent appendicitis and PCKD, failed conservative management, and comorbid conditions that may obscure the diagnostic process.