案例報告：成人之臍尿管囊腫感染以不常見的臨床表現

鄭偉權¹、顏元豪²、蔡牧堯¹

高雄長庚紀念醫院¹泌尿科；²整型外科

Case report: An infected urachal cyst in an adult with unusual presentation

Wei-Quen Tee¹, Yuan-Hao Yen², Mu-Yao Tsai¹

Department of Urology¹and Plastic Surgery², Chang Gung Memorial Hospital, Kaohsiung Medical Center, Chang Gung University College of Medicine, Kaohsiung, Taiwan.

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. Involution of the urachus is usually complete at birth, but incomplete involution results in urachal abnormalities. The four main types of urachal remnants are patent urachus or urachal fistula, umbilical-urachal sinus, vesicourachal diverticulum, and urachal cyst.

We present a case of an infected urachal cyst in an adult with unusual presentation. This 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. She also denied trauma or fell down history.  Physical examination showed bilateral mid-lower abdomen erythematous skin change with local heat and tenderness. Initial lab data revealed leukocytosis (WBC: 21.7k/uL) with elevated segment percentage (86.5%), 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. Fever episode was noted and the abdominal skin erythematous lesion with tenderness getting worse. Follow-up lab data showed progressive WBC and CRP levels. Augmentin shifted to Ceftaroline. Abdominal CT followed-up reported supravesical ill define soft tissue density mass lesion (47mm), DDx: urachal tumor, infected urachal cyst/diverticulum, 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.

Discussion

The incidence rate of urachal anomalies has varied among studies. In the adult population, the incidence of urachal anomalies is approximately 1 in 5000. Typically, cyst formation occurs in the lower one-third of the urachus, which is relatively small. The clinical findings included umbilical drainage, lower abdominal pain, umbilicus palpable mass, infection, or asymptomatic. Urachal anomalies may not be detected until adulthood and patients may present with infection, hemorrhage, or tumor (adenocarcinoma). Because of various symptoms, infected urachal cysts have been frequently confused with appendicitis or Meckel’s diverticula. Urachal cyst infections predispose patients to many acute complications, including bladder fistula formation, cyst rupture, peritonitis, necrotizing fasciitis, and sepsis. The treatment of choice for a urachal abscess in the adult patient included broad-spectrum antibiotics and drainage or debridement.