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Case 8

History:

42 year old male presenting with green umbilical discharge

Findings:

CT of the abdomen showing non specific midline soft tissue mass near the umbilical region with intrinseque air.

Diagnosis:

Urachal Cyst

Discussion:

The urachus, is a midline tubular structure that extends upward from the anterior dome of the bladder toward the umbilicus. It typically involutes before birth, remaining as a fibrous band with no known function. However, persistence of an embryonic urachal remnant can give rise to various clinical problems, not only in infants and children but also in adults. Congenital urachal anomalies are twice as common in men as in women.

There are 4 types of urachal anomalies: patent urachus (50%), umbilical-urachal sinus (15%), vesicourachal diverticulum (about 3–5%) and urachal cyst (about 30%).

Urachal tract remnants that remain patent are often subject to infection and are often confused with a wide spectrum of midline intra-abdominal or pelvic inflammatory disorders at clinical examination and with malignant tumors at imaging. Urachal adenocarcinoma is rare but an important finding to look for. Urachal tumors are typically silent due to their extraperitoneal location; as a result the majority of cases can present with local invasion or metastatic disease. Many of the features of urachal remnant diseases, including congenital lesions with or without superimposed infection and tumors, are well displayed at sagittal US.

CT helps confirm the US findings and discloses the nature and local extension of the disease as well as any systemic metastases.

References:

  • Cilento BG, Jr, Bauer SB, Retik AB, Peters CA, Atala A. Urachal anomalies: defining the best diagnostic modality. Urology 1998; 52:120-122. Khati NJ, Enquist EG, Javitt MC. Imaging of the umbilicus and periumbilical region. RadioGraphics 1998; 18:413-431.
  • Schubert GE, Pavkovic MB, Bethke-Bedurftig BA. Tubular urachal remnants in adult bladders. J Urol 1983; 127:40-42.
  • Berman SM, Tolia BM, Laor E, Reid RE, Schweizerhof SP, Freed SZ. Urachal remnants in adults. Urology 1988; 31:17-21.
  • Brick SH, Friedman AC, Pollack HM, et al. Urachal carcinoma: CT findings. Radiology 1988; 169:377-381.
  • Friedland GW, Devries PA, Matilde NM, Cohen R, Rifkin MD. Congenital anomalies of the urinary tract. In: Pollack HM, eds. Clinical urography. Philadelphia, Pa: Saunders, 1990; 559-787.
  • Blichert-Toft M, Nielsen OV. A congenital patent urachus and acquired variants. Acta Chir Scand 1971; 137:807-814.
  • Blichert-Toft M, Koch F, Nielsen OV. Anatomic variants of the urachus related to clinical appearance and surgical treatment of urachal lesions. Surg Gynecol Obstet 1973; 137:51-54.