The urachus is the remnant of the cloaca and allantois. It normally involutes and results in a fibrous cord between the umbilicus and the bladder dome in the preperitoneal space.

62-year-old woman had the underlying disease of hypertension under medication control and asthma history without medication control. She suffered from lower abdominal pain for 3days with associated symptoms of mid-lower abdomen skin erythematous change. She denied fever, nausea, vomiting, change of bowel habits, or dysuria. Physical examination showed bilateral mid-lower abdomen erythematous skin change with local heat and tenderness. Initial lab data revealed leukocytosis (WBC: 21.7k/uL), thrombocytosis (432k/uL) and elevated CRP (230 mg/L). Abdominal CT showed multiple hyperdense lesions on the lower abdominal wall, which need to rule out hematoma or abscess formation. Initially, she was admitted under the impression of sepsis focusing on abdominal wall cellulitis and antibiotic treatment with Augmentin.

After 7days of antibiotic treatment, the symptoms were not relieved but progressed. Abdominal CT followed-up reported lower abdomen skin thickening, subcutaneous fat straining with lobulated fluid densities, suspected inflammation with abscess formation. Thus, we operated on urachal cyst resection with partial cystectomy. Fibercystoscope showed no diverticulum or bladder lesion. Much of the pus drainage out once the incision wound was created. The plastic surgeon was consulted for abdominal wall fasciotomy and fasciectomy. The infected site was extending to the groin and flank. Then she was under wound care and antibiotic treatment. She received a fasciocutaneous rotation flap after the infection was under control. The pathology report of the urachus and bladder wall revealed xanthogranulomatous inflammation.

If the infectious urachal cyst progresses to necrotizing fasciitis, maximum wound debridement and partial cystectomy may be needed to cure the condition