Appendiceal appearances: the great imitator

A 7 year old boy presented with a four week history of nocturnal back pain, weight loss, lethargy, intermittent temperatures, and new onset of scoliosis. On examination, he was clinically anaemic and cachectic, with widespread lymphadenopathy. There was an ill defined fibrous feeling mass overlying the right 7th–10th postero‐lateral rib area. The thoracolumbar scoliosis was positional and related to discomfort on movement. There was no organomegaly and abdominal examination was unremarkable. Haemoglobin was 87 g/l, white blood cell count was normal, and INR was 1.5. Childhood malignancy was suspected.

The antero‐posterior chest radiograph showed a mild dorsal scoliosis with lateral soft tissue swelling overlying the 9th–10th ribs. MRI scan showed a 6×4×4 cm partly solid partly cystic lesion lying postero‐lateral to the right lobe of the liver and immediately lateral to the upper pole of the kidney (see fig 1). This abscess also resulted in associated changes to the right intercostal muscles.

Figure 1 MRI scan of the thorax (T2 weighted image) illustrating abscess. Note the associated thoracic wall changes.

Surgical intervention revealed a perforated retrocaecal appendix, liver adherence to the ribs and diaphragm, and an abscess in the posterior aspect of the right liver lobe. The liver abscess pus was negative on culture and the child recovered fully following a course of intravenous antibiotics.

Recognised presenting features of acute appendicitis may be minimal or absent in children and may imitate childhood malignancy.¹ Radiologists have a major role in suggesting complicated inflammatory disease of the appendix as a cause.