URACHAL

CYST

URINARY

BLADDER

Fig. 16.9 Diagrammatic representation of a urachal cyst

Fig. 16.10 Abdominal ultrasound showing a urachal cyst

–It occurs primarily in the lower one-third of the urachus and less frequently in the upper one-third.

–Urachal cysts are usually small but vary considerably in size.

–They become symptomatic when they enlarge.

–Sometimes, they are found as incidental masses during routine examination.

–As with other urachal anomalies, infection is the most common complication of urachal cyst, and the majority of cysts are infected at the time of diagnosis.

–Rarely, spontaneous rupture of an infected cyst into the abdominal cavity leads to localized or generalized peritonitis.

–Percutaneous needle biopsy or fluid aspiration is mandatory for diagnosis and treatment.

–Total exciton of the cyst is essential because there is a 30 % reinfection rate and carcinoma may develop in an unresected or incompletely resected urachal. cyst.

–CT or US are helpful for the diagnosis and shows a fluid-filled cavity in the midline lower abdominal wall.

–Eggshell calcification of the cyst wall is rarely seen.

–Infected urachal cyst manifests as wall thickening and demonstrates an attenuation higher than that of water at CT and soft-tissue components and mixed echogenicity at US.

16.5Tumors and Urachal Remnants

•Urachal tumors are extremely rare and can be benign or malignant.

•Benign urachal tumors include:

–Adenomas

–Fibromas

–Fibroadenomas

–Fibromyomas

–Hamartomas

•Malignant urachal neoplasms represent less than 0.5 % of all urinary bladder cancers.

•The normal urachus is commonly lined by transitional epithelium, but it was found that urachal carcinoma predominantly are adenocarcinoma (90% of cases) and 75% of these cases are mucin producing.

•This is probably due to the metaplasia of the urachal mucosa into columnar epithelium followed by malignant transformation.

•The remaining urachal carcinomas are transitional, squamous, or anaplastic carcinomas.

•34 % of bladder adenocarcinomas are of urachal origin.

•These tumors are most commonly seen in patients 40–70 years of age, two-thirds of whom are men.

•Urachal carcinomas may be solid, cystic, or a combination of the two.

•Urachal tumors are typically silent because of their extraperitoneal location.

•The majority of patients exhibit local invasion or metastatic disease at presentation.

•Ninety percent of urachal carcinomas arise in the juxta vesical portion of the urachus and

extend superiorly toward the umbilicus and inferiorly through the bladder wall.

•A minority of urachal carcinomas are located in the middle of the urachus (6 % of cases) or near the umbilical end (4 %).

•50–70 % of urachal carcinomas produce psammomatous calcifications that may be punctate, stippled, or curvilinear and peripheral.

•The prognosis is generally poor because these tumors are usually clinically silent and discovered late after it has reached a large size and extended locally or metastasized. Metastases occur initially in the pelvic lymph nodes, followed by systemic metastases to the lung, brain, liver, and bone.

•It was shown that many of the features of urachal remnants, including congenital lesions

with or without superimposed infection and tumors, can be easily demonstrated by abdominal ultrasound.

•CT is more helpful in confirming the diagnosis and determining the extent of the disease.

16.6Management

•Asymptomatic remnants are managed conservatively.

•Surgical excision should be avoided for patients younger than 1 year because the remnant might spontaneously disappear.

•Infective complications of urachal remnants are treated with antibiotic therapy for the acute infection followed by surgical excision

•The presence of an abscess requires drainage preferably percutaneous drainage under ultrasound guidance and once the infection subsides, the remnant should be excised.

•It was reported that up to 30 % of infected urachal cysts recurred when not excised.

•It is generally recommended that all urachal remnants should be excised to avoid recurrent infection and because of possible malignant transformation later in life.

•Surgical excision is usually done through a transverse or midline infra-umbilical incision.

•Recently and as a result of advances in minimal invasive surgery, laparoscopic excision of urachal remnants was shown to be feasible and safe. The advantages of laparoscopic excision of urachal remnants include:

–It minimizes the morbidity associated with open surgery

–A shorter hospital stay

–Faster recovery

–Better cosmetic result

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