Appendix intussusception: a challenging differential diagnosis

Abstract

Appendix intussusception: a challenging differential diagnosis A 68-year-old man was admitted to our hospital for diffuse abdominal pain, bloating and diarrhoea alternating with constipation for the last 6 days. On examination, abdominal distension was noticed with pain in the right iliac fossa (RIF), worsened with palpation, positive Blumberg sign and normal digital rectal examination. Plain abdominal X-ray showed mild intestinal distension in the lower quadrant of the abdomen and some air fluid levels. Blood tests revealed leucocytosis with neutrophilia, mild normochromic normocytic anaemia and high levels of erythrocyte sedimentation rate, fibrinogen and C-reactive protein. The abdominal ultrasound detected a hypoechoic mass in the RIF, without other compelling features. Owing to these non-specific findings, an abdominal computed tomography (CT) scan was performed, which demonstrated thick caecal walls (1.5 cm), particularly on the medial segment, with an 8-mm appendix, more consistent with plastron appendicitis, rather than a caecal tumour. Therefore, the patient received intravenous antibiotics and analgesics, with favourable evolution. Owing to several risk factors (gender, age, clinical presentation and atypical imaging appearance), a high suspicion for colorectal cancer persisted. A complete colonoscopy was performed after remission of symptoms and inflammatory response. It identified marked oedema, hyperaemia of the caecum and narrowed appendix orifice that expressed pus and fibrin (Fig. 1). Serial biopsies showed inflammatory changes that correlated with negative Carbohydrate antigen 19-9 (CA 19-9) and Carcinoembryonic antigen (CEA). Consequently, the patient was discharged with oral antibiotics and analgesics for another week and was readmitted for the surgical treatment after 2 months. After readmission, a second abdominal CT scan was performed, which revealed remission of caecal inflammation and raised the suspicion of partial appendix intussusceptions (Fig. 2). A laparoscopic appendectomy with caecum base resection was performed. Macroscopic examination of the specimen confirmed the diagnosis (Fig. 3).