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Robotic-assisted Laparoscopic Excision of Urachal Sinus found to be Mucinous Carcinoma: A Case for Umbilectomy

We present the case of a 26-year-old African-American female with umbilical discharge who was found to have a urachal sinus extending from the bladder to the level of the umbilicus.

Authors: Nathan A. Bockholt1, Kenneth G. Nepple1, Laila Dahmoush2, Chad R. Tracy

1. University of Iowa Departments of 1Urology and 2Pathology, Iowa City, Iowa

 
Corresponding Author: Chad R Tracy, MD, University of Iowa, Department of Urology, 200 Hawkins Dr, 3RCP, Iowa City, IA 52242-1089.  E-mail: [email protected]

Abstract
Urachal anomalies are rare and generally asymptomatic. However, the development of infection and malignancy suggest the case for excision regardless of age. Numerous reports have shown that leaving the umbilicus intact following remnant excision is feasible despite the risk of malignancy. We present the case of a 26-year-old African-American female with umbilical discharge who was found to have a urachal sinus extending from the bladder to the level of the umbilicus. There was no radiographic evidence of malignancy on CT scan. Robotic-assisted laparoscopic excision of the remnant including bladder cuff and complete umbilectomy was performed. Surgical pathology showed mucinous carcinoma on the umbilical portion of the specimen only. Radiographic imaging is not sensitive enough to evaluate microscopic urachal carcinoma and serious consideration should be given for complete excision of the urachal sinus including umbilicus due to the risk of malignancy. Urachal carcinoma isolated to the umbilical segment of a urachal sinus, without clinical or radiographic evidence of malignancy, is a rare entity and should be considered during surgical intervention.

 

Introduction
 
The urachus is a remnant derived from the obliteration of the embryologic allantois, extending from the dome of the bladder to the umbilicus and anatomically termed the medial umbilical ligament [1]. Urachal anomalies are found in ≤ 2% of adults with urachal cysts and are identified in 1 out of every 5000 births [2-4]. Urachal anomalies can be described based on the extent of urachal patency as a patent urachus (entire tract patent), urachal cyst/alternating sinus, umbilical-urachus sinus (umbilical side patent), and vesicourachal diverticulum (bladder side patent) occurring in 50%, 30%, 15%, and 3-5% of urachal abnormalities, respectively [4-6].
Despite the routine use of computer-assisted tomography for the diagnosis of urachal remnants/anomalies since the early 1980s [7-9], it is difficult to differentiate  malignancy from a benign process, stressing the importance of complete excision of the tract and umbilicus[10,11]. Numerous reports have confirmed the malignant potential of these lesions, particularly in adults, raising the question of earlier intervention in the paediatric population. A retrospective study by Ashley et al showed that over 50% of adults with urachal anomalies required more extensive surgical intervention with partial or radical cystectomy and over 50% were malignant, with patient age (> 55 years) and haematuria being the strongest predictors of urachal malignancy [12]. However, some authors argue that urachal remnants during childhood and the development of carcinoma later in life bear no connection. In fact, a non-operative approach in the management of urachal anomalies in the paediatric population has been proposed, especially after adequately draining urachal cysts, due to the rate of obliteration over time [6,13].
In addition to the various approaches regarding extent of surgical excision, various surgical techniques have been described as well. Initial minimally invasive surgical approaches were described in 1992 and 1993 by Neufang et al [14] and Trondsen et al [15], who performed the first reported laparoscopic excisions of a urachal fistula and sinus, respectively. More recent reports have incorporated robotic assistance using the da Vinci® surgical robotic system (Intuitive Surgical Inc. Sunnyvale, CA) [16-19]. In an effort to make the procedure less invasive, Patrzyk et al reported the first reported case of laparoendoscopic single site surgery for umbilectomy and bladder cuff excision [20].

 

Case Report
 
A 26-year-old African-American female presented with periumbilical abdominal pain, discharge from the umbilicus, and occasional urinary tract infections with symptoms present for 10 years. A CT scan of the abdomen and pelvis with contrast and 5 mm cuts was obtained, revealing a urachal remnant, favored to be a patent urachal sinus extending from the bladder dome to the level of the umbilicus without evidence of calcification or enhancement (Figure 1).
 

Figure 1. CT scan of the abdomen and pelvis with contrast and 5 mm cuts revealing a urachal remnant, favored to be a patent urachal sinus extending from the bladder dome to the level of the umbilicus without evidence of calcification or enhancement. Otherwise grossly normal urinary bladder.
CT scan of the abdomen and pelvis with contrast and 5 mm cuts revealing a urachal remnant, favored to be a patent urachal sinus extending from the bladder dome to the level of the umbilicus without evidence of calcification or enhancement.  Otherwise grossly normal urinary bladder.
Cystoscopy was performed, showing evidence of the urachal remnant near the dome of the bladder without suspicion of malignancy.
Robotic-assisted laparoscopic urachal excision was completed using 4 port sites in a configuration 4 cm cephalad to the typical position for prostatectomy, with a 12 mm supraumbilical camera port, two 8 mm da Vinci surgical ports 6 cm inferior to the camera port and adjacent to the rectus muscle, and a 5 mm assistant port in the mid-axillary line at the level of the umbilicus. A prominent urachal sinus approximately 1 cm in diameter tracking from the midline down to the dome of the bladder was visualized. The urachal sinus was then isolated from the bladder up to just below the umbilicus and the medial umbilical ligaments were split. The bladder was insufflated with carbon dioxide through the urethral catheter and a wide margin of the bladder dome circumferentially around the insertion of the urachal sinus was marked with cautery and then excised. The bladder was closed in 2 layers with 2-0 vicryl to obtain a watertight closure. A Jackson-Pratt drain was placed in the pelvis through the right lateral assistant port site. The urachal sinus was doubly clipped near the umbilical portion with hem-o-lok clips (Teleflex Medical, Durham, NC). The bladder portion of the remnant was then removed through the camera port and the umbilical portion was removed in an open fashion.
The umbilicus was grasped with a Kocher clamp, excised circumferentially, and extended down through the fascia, taking a cone of subcutaneous tissue with the specimen in order to completely excise the proximal portion of the umbilical sinus. The fascia was incised to identify the clipped portion of the urachal remnant just below the level of the fascia. The fascia was closed and an umbilicoplasty was performed using subdermal suturing.
The patient recovered well and was discharged on postoperative day 2 with a Foley catheter in place.  She returned to clinic 10 days later and a cystogram verified no extravasation and a bladder capacity >210 cc. The incision sites were well-healed and the umbilicoplasty was cosmetically pleasing to the patient. Surgical pathology showed mucinous carcinoma arising in the urachal remnant on the umbilical side only (Figure 2).

 

Figure 2. Microscopic examination. Resected urachal remnant reveals a tract lined by intestinal type epithelium which gives rise to an invasive mucinous carcinoma with lakes of mucin. Nests of adenocarcinomatous cells are seen floating. The invasive carcinoma was 0.8 cm in greatest dimension and all surgical margins were free of tumour.
Microscopic examination. Resected urachal remnant reveals a tract lined by intestinal type epithelium which gives rise to an invasive mucinous carcinoma with lakes of mucin. Nests of adenocarcinomatous cells are seen floating. The invasive carcinoma was 0.8 cm in greatest dimension and all surgical margins were free of tumour.

 

Discussion
 
Despite the many successful reported outcomes using standard laparoscopy and laparoscopy with robotic assistance, there remains controversy regarding the extent of resection involving urachal anomalies. Several recent studies in the minimally invasive literature advocate for umbilical retention without excision of the entire umbilical tract depending on mass size, lack of lymphadenopathy, findings suggestive of benign disease on exam or CT scan, and for cosmetic reasons [2,12,20-23]. Cadeddu et al reported results on 4 patients with urachal cysts who underwent successful laparoscopic excision [2]. The authors advocated wide excision of the urachal remnant from immediately caudal to the umbilicus down to the bladder dome, leaving the umbilicus intact due to the benign appearance of the remnant and lack of communication.  Okegawa et al performed laparoscopic excision of 6 urachal sinuses where the surgical resection extended just cephalad to the bladder up to the umbilicus. Again, the umbilicus was left intact as it was felt to offer a superior cosmetic result [21]. This approach has also been advocated by surgeons performing robotic surgery. Kim et al performed robotically-assisted urachal excisions on 4 patients, leaving the umbilicus intact due to small mass size, the absence of lymphadenopathy, and lack of concerning intraoperative findings [22]. Even when urachal carcinoma is certain, some authors continue to advocate that umbilectomy may not need to be performed [23].
Long-term follow-up and prospective studies in patients who have undergone incomplete excision or observation of urachal anomalies are lacking. Our patient presented with a radiographically benign appearing urachal sinus without evidence of calcification or enhancement, but subsequent excision showed urachal carcinoma in the umbilical segment. Urachal carcinoma often presents on CT scan as a complex calcified supravesicular mass located in the midline [24]. Other groups have reported on the malignant potential of the umbilical portion, advising removal. Carcinomas of urachal origin often present with disease at stage pT3 or higher due to their silent nature, predilection for local growth, and metastatic potential. Gopalan et al reported on 24 cases of urachal carcinoma where 29% recurred locally and the incidence of local recurrence was higher in patients who underwent a partial cystectomy alone (37.5%) versus those who had a more radical surgery (27%) [25]. 37.5% of patients in the study had metastatic disease. With urachal carcinoma comprising only 0.35-0.7% of bladder cancer cases and 22-35% of vesical adenocarcinomas, it can be low on a clinician’s differential despite the potential for advanced disease [10,26]. Surgical margins also play a significant role in local recurrence and survival. Five-year cancer-specific survival has been shown to range from 0-17% to 53-77% for positive and negative surgical margin status, respectively [27-29].
Malignancy often presents with a bladder mass located at the dome found on cystoscopy after an episode of hematuria, but even the urachal remnants that appear benign warrant surgical treatment due to the risk of infection and potential for malignant transformation. Surgical excision has been the mainstay treatment for known urachal carcinoma with en bloc excision of the bladder dome, urachal ligament, posterior rectus abdominis fascia and umbilicus [10,27,28]. A retrospective review completed by Siefker-Radtke et al, examining 42 patients with urachal carcinoma, found that no patient had disease confined to the urachal ligament [27].  Though en bloc resection including the urachal ligament and umbilicus was not statistically associated with survival, 13 of the 16 long-term survivors underwent the en bloc resection and umbilectomy. The Mayo Clinic’s 50-year experience with the disease showed that failure to perform umbilectomy was univariately associated with death [28].
Whereas urachal carcinoma demands radical excision, there remains controversy over the extent of resection surrounding urachal anomalies without obvious mass and whether or not observation is suitable for various age groups. The predilection for malignancy in urachal remnants has been well supported, but challenging to foretell based on presenting signs, symptoms, and preoperative imaging. Urachal remnants without epithelium are thought to be low risk for malignant potential even in the younger population.  Many urachal remnants do show adenomatous changes [27], but predicting histopathological composition based on the patient’s presenting signs and symptoms is difficult [30]. Sheldon et al showed that 7% of patients undergoing resection for urachal carcinoma had disease involving the umbilicus [10] and a retrospective study completed by Ashley et al confirmed that >50% of the urachal lesions in adults were carcinoma [12].
While some promote observation of urachal remnants, others would argue that if remnants are not excised soon after identification, the resulting urinary stasis, infection, and subsequent infection predisposes the patient to malignancy [12,13]. Observation has been described in the younger paediatric population, as urachal remnants can be physiological and resolution is possible by 6 months of age without requiring surgical intervention. After 6 months of age, resolution becomes less likely and excision is advised [6]. Regarding infected remnants in children, drainage alongside antibiotics has been proposed reasonable, as long as follow-up including serial imaging is conducted [13]. There should be little argument over the need for remnant excision including umbilectomy when tumour is present, regardless of age.  Given that the 5-year survival for urachal carcinoma fluctuates between 40% and 49%, there is little room for error in leaving behind a positive surgical margin.  Patients with tumour confined to the urachus, bladder and peri-urachal fat can reach an overall survival of 88% despite many malignancies presenting at an advanced stage [27-29,31].
As more minimally invasive techniques grow in popularity, it is important to follow oncologic principles established in open surgery.  While indications for en bloc resection and umbilectomy are relatively straightforward, there are no consistent findings predicting oncologic transformation in patients without an identifiable mass.  In the current case, the patient was a young woman with a symptomatic urachal sinus with no other identifiable risks for urachal carcinoma.  Nevertheless, surgical pathology revealed mucinous carcinoma only in the umbilical portion of the resected specimen, which would have, presumably, been left in place with an umbilical-sparing procedure, leading to a high risk of recurrent malignancy later in life.

 

Conclusions
Urachal anomalies and urachal carcinoma are uncommon.  En bloc excision of the bladder dome, urachal ligament, posterior rectus abdominis fascia and umbilicus is justified for the best oncologic outcomes in patients with a preoperatively diagnosed urachal mass.  Long-term studies in patients who have underwent incomplete excision of urachal anomalies without obvious mass are lacking, nonetheless, patients who retain their umbilicus after remnant excision require close follow-up.  Umbilectomy along with urachal sinus excision is warranted to prevent cancer recurrence and progression in this subset of the population, despite the absence of macroscopic evidence of malignancy on cystoscopy, CT scan, or physical exam.

 

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Date added to bjui.org: 12/04/2011 


DOI: 10.1002/BJUIw-2011-005-web

 

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