A 31-year-old man came to our hospital with left hip pain and intermittent fever for 1 month. For nearly a year, the patient occasionally has abdominal distention which alleviated after defecation. The frequency of defecation was about once every two days. The mass was seen as a reddish skin color around the anterior superior iliac spine which was painful and palpated.
The laboratory examination revealed white blood cell 13.25 x 109/L (3.5-9.5), neutrophil percentage 85% (40-75), platelet 420 x 109/L (125-350), C-reactive protein 82.6 mg/L (0-10) and erythrocyte sedimentation rate 48 mm/h (0-20). The tumor-related biomarkers (AFP, CEA, PSA, CA19-9, ferritin), serum tuberculosis antibodies and T-cell spot test for tuberculosis infection (T-TB.Spot) were within normal limits. The whole abdomen CT and pelvic contrast-enhanced MRI were performed. The imaging revealed a left PA (Figures 1A,B) Colonoscopy revealed mucosal stiffness and multiple polyps on the ascending colon (Figure 1C). Then, the mucosal biopsy of ascending colon was performed. To sum up, we think that it may be the PA secondary to inflammatory bowel disease. But pathology was not in line with the typical manifestations of inflammatory bowel disease.