(Radiographics. 2001;21:965-969.)
© RSNA, 2001
Best Cases from the AFIP: Mucinous Colloid Adenocarcinoma of the Urachus1
Francis J. Mangiacapra, MD,
Janet L. Scheraga, MD and
Lee A. Jones, MD
1 From the Department of Radiology, Upstate Medical University, 750 E Adams St, Syracuse, NY 13210 (F.J.M.); and Departments of Radiology (J.L.S.) and Pathology (L.A.J.), Veterans Administration Medical Center, Syracuse, NY. Received February 7, 2001; revision requested March 7 and received April 10; accepted April 11. Address correspondence to F.J.M. (e-mail: mangiacf@upstate.edu).
 |
History
|
|---|
A 55-year-old man presented with a complaint of abdominal pain of 2 months duration. The patient was found to have gross hematuria, and during his evaluation he stated that he had been passing mucus in his urine for about 4 years. The patient had not observed any umbilical discharge. The patient had undergone abdominal surgery for pyloric stenosis as a child and had a history of smoking. Results of the physical examination were unremarkable.
|
Imaging Findings
|
|---|
Radiography of the abdomen and pelvis was performed during the initial evaluation. Abdominal radiography revealed no renal or ureteral calculi; however, a calcified mass was identified in the midline projecting over the left sacrum (Fig 1). Findings at renal ultrasonography (US) were normal, but interrogation of the supravesical region revealed a 7 x 4-cm mass with mixed echogenicity that indented the dome of the bladder (Fig 2).
View larger version (127K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 2a. (a) Longitudinal sonogram of the bladder demonstrates a heterogeneous mass (*) arising near the dome of the urinary bladder (arrow). (b) Transverse view through the superior portion of the lesion demonstrates the well-defined margin of the mass (*).
|
|
View larger version (110K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 2b. (a) Longitudinal sonogram of the bladder demonstrates a heterogeneous mass (*) arising near the dome of the urinary bladder (arrow). (b) Transverse view through the superior portion of the lesion demonstrates the well-defined margin of the mass (*).
|
|
Contrast material–enhanced computed tomography (CT) of the abdomen and pelvis was performed to evaluate the US findings. A 4 x 4 x 10-cm mass that extended from the dome of the bladder superiorly in the anterior abdomen was identified (Fig 3). Peripheral calcification in the mass was confirmed.
View larger version (94K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 3a. (a) Axial contrast-enhanced CT scan of the pelvis obtained through the superior portion of the lesion demonstrates a moderate amount of peripheral calcification with a central area of low attenuation. (b) Another CT scan obtained at a lower level shows that the mass extends down to and appears contiguous with the dome of the bladder.
|
|
View larger version (101K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 3b. (a) Axial contrast-enhanced CT scan of the pelvis obtained through the superior portion of the lesion demonstrates a moderate amount of peripheral calcification with a central area of low attenuation. (3) Another CT scan obtained at a lower level shows that the mass extends down to and appears contiguous with the dome of the bladder.
|
|
|
Pathologic Evaluation
|
|---|
Cystoscopy was performed and revealed an area of ulceration in the dome of the bladder (Fig 4). Biopsy specimens from the bladder wall lesion contained adenomatous glands with mild to moderate dysplasia and focal areas of local direct invasion suggestive of malignancy.
About 2 months after the initial presentation, the patient underwent definitive surgery, including excision of the mass with partial cystectomy. At surgery (Figs 5, 6), a large cystic mass was identified with a smaller solid mass that extended from the superior bladder wall and caused ulceration of the bladder mucosa. Histologic analysis of the resected specimen demonstrated a mucin-secreting epithelium containing areas of calcification within the mucinous debris (Fig 7). The cell type of the solid mass proved to be well-differentiated mucinous colloid adenocarcinoma, consistent with a urachal origin. The cystic mass was identified as a urachal cyst.
View larger version (161K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 7a. (a) Low-power photomicrograph (original magnification, x22; hematoxylin-eosin stain) of a resected specimen from the junction of the urinary bladder and the conjoined mass shows complex mucin-secreting epithelium (black arrow) overlying a zone of fibrous connective tissue extensively infiltrated by mucin and containing foci of calcification (white arrow). To the right is fibrous connective tissue containing lymphocytic aggregates, beyond which (further right and not shown) is uninvolved smooth muscle of the bladder wall. (b) High-power photomicrograph (original magnification, x225; hematoxylin-eosin stain) shows the tall simple to pseudostratified columnar epithelium, including goblet cells (arrows), which characterizes mucinous colloid adenocarcinoma of urachal origin.
|
|
View larger version (139K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 7b. (a) Low-power photomicrograph (original magnification, x22; hematoxylin-eosin stain) of a resected specimen from the junction of the urinary bladder and the conjoined mass shows complex mucin-secreting epithelium (black arrow) overlying a zone of fibrous connective tissue extensively infiltrated by mucin and containing foci of calcification (white arrow). To the right is fibrous connective tissue containing lymphocytic aggregates, beyond which (further right and not shown) is uninvolved smooth muscle of the bladder wall. (b) High-power photomicrograph (original magnification, x225; hematoxylin-eosin stain) shows the tall simple to pseudostratified columnar epithelium, including goblet cells (arrows), which characterizes mucinous colloid adenocarcinoma of urachal origin.
|
|
|
Discussion
|
|---|
The urachus is a remnant of the intraembryonic portion of the allantois. The urachus is typically closed at birth and is identifiable only as a fibrous band, the median umbilical ligament, which extends from the bladder dome to the umbilicus. The urachus is an extraperitoneal structure located in the space of Retzius (which is bounded by the transversalis fascia ventrally and the parietal peritoneum dorsally). If the urachus persists beyond birth, it can give rise to a number of congenital and acquired disorders (1).
Congenital disorders include a patent urachus, urachal sinus, vesicourachal diverticulum, urachal cyst, and umbilical-urachal sinus. A patent urachus is simply a fistula through the urachus between the bladder and the umbilicus. A urachal sinus is patent only from the urachus to the umbilicus. A vesicourachal diverticulum is a communication only between the bladder dome and the urachus. A urachal cyst does not communicate with either the bladder or the umbilicus. Lastly, an umbilical-urachal sinus is a cystic dilatation of the urachus, which periodically empties into either the bladder or the umbilicus.
Acquired conditions relating to these congenital anomalies include infection, which is the most common complication, as well as benign and malignant neoplasms. Benign neoplasms of the urachus include adenomas, fibromas, fibroadenomas, fibromyomas, and hamartomas and are extremely rare. These urachal remnant anomalies and diseases can be radiologically evaluated with US or CT, with fistulography or cystography performed to demonstrate contiguity with the urachus (1,2).
Urachal carcinoma is a rare neoplasm, accounting for only 0.01% of all malignancies. Urachal carcinoma involves the bladder by infiltration, constituting up to 0.34% of bladder carcinomas (3–5). Adenocarcinoma of the urachus is by far the most common type (90% of cases), although there are reports in the literature of isolated cases of tumors of different cell types such as squamous cell carcinoma, transitional cell carcinoma, sarcoma, teratoma, rhabdomyosarcoma, and neuroblastoma (4,6–9). Conversely, 34% of bladder adenocarcinomas are of urachal origin, and an adenocarcinoma arising from the dome of the bladder should be considered urachal in origin until proved otherwise (2,3).
Urachal carcinoma has a male predilection and is most commonly seen in patients between 40 and 70 years of age (10). Urachal carcinoma is usually associated with a poor prognosis, since the tumor produces few symptoms until late in the course of the disease. Henly et al (11) reported in their study that 95% of patients presented with muscle invasion or metastatic cancer at the time of diagnosis. Typically, the cancer spreads locally in the space of Retzius, abdominal wall, and peritoneum, which allows for a long silent course before detection (3,11). A urachal cyst may become symptomatic when infection develops or occasionally when a urachal sinus develops and an umbilical discharge is produced. Symptomatic lesions of the urachus are usually painful but may cause no dysuria or hematuria unless there is involvement of the bladder or perivesicular tissues. Our patient had mucinuria for a period of 4 years; however, this symptom alone did not lead him to seek medical attention. Mucinuria is an uncommon urologic symptom, occurring in about 25% of patients with urachal tumors, but histologic analysis reveals mucin production in about 75% of cases (10,12). Mucinuria can also occur from a primary adenocarcinoma of the bladder, although this tumor is much less common than transitional cell carcinoma.
Mucinous tumors also tend to contain calcifications. Since 90% of urachal carcinomas arise in the juxtavesicular portion of the urachus (13), the radiographic finding of supravesical calcification associated with a bladder lesion has been considered nearly pathognomonic for urachal adenocarcinoma (14–16). However, calcification is seen in less than 5% of cases at radiography (14,17). CT is more sensitive in the detection of calcification in the lesion, and a stippled pattern has been suggested as being highly suggestive of urachal carcinoma (16).
CT is also helpful in differentiating between urachal carcinoma and primary bladder carcinoma arising in the mucosa of the bladder apex, since the latter usually has less of an extravesicular component (17,18). According to Narumi et al (18), the extension of urachal carcinoma along the space of Retzius anterosuperior to the bladder dome helps differentiate it from advanced bladder carcinoma, which predominantly shows intravesical growth. However, pure squamous cell carcinoma of the bladder dome may display predominantly extravesical growth (18).
The characteristic midline position of urachal carcinoma just above the urinary bladder and directly posterior to the linea alba is an important factor in the CT diagnosis (19). Another CT characteristic of urachal carcinoma is the central low attenuation of the lesion, a finding consistent with the mucin content of the tumor (20). Although US may be helpful in identifying the supravesicular component of the lesion, which is suggestive of a diagnosis of urachal carcinoma, CT or magnetic resonance imaging adds more information about the extent of local disease as well as nodal metastasis (13,18,19).
Treatment options for urachal carcinoma are surgical: either (a) en bloc radical cystoprostatectomy with wide excision of the urachus and umbilicus or (b) partial cystectomy with urachectomy. Urachal carcinoma is almost uniformly resistant to chemotherapy and radiation therapy (10). Several studies have shown that partial cystectomy with urachectomy can be as effective as more radical excision and causes less morbidity in cases of well-differentiated adenocarcinoma (11,21). Recent studies of cases treated with partial cystectomy revealed a 5-year overall survival rate of 43% (11, 21). Our patient underwent excision of the urachal mass with partial cystectomy and at 1-year follow-up has no evidence of recurrence.
|
Acknowledgments
|
|---|
We thank J. C. Trussell, MD, Department of Urology, Upstate Medical University, for providing intraoperative photographs for correlation.
|
Footnotes
|
|---|
Index terms: Genitourinary system, neoplasms, 839.3233 Urachus, 839.3233
|
References
|
|---|
-
Khati NJ, Enquist EG, Javitt MC. Imaging of the umbilicus and periumbilical region. RadioGraphics 1998; 18:413-431.[Abstract]
-
Yu JS, Kim KW, Lee HJ, Lee YJ, Yoon CS, Kim MJ. Urachal remnant diseases: spectrum of CT and US findings. RadioGraphics 2001; 21:451-461.[Abstract/Free Full Text]
-
Ravi R, Shrivastava BR, Chandrasekher GM, Prahlad S, Balasubramanian KV, Mallikarjuna VS. Adenocarcinoma of the urachus. J Surg Oncol 1992; 50:201-203.[Medline]
-
Chow YC, Lin WC, Tzen CY, Chow YK, Lo KY. Squamous cell carcinoma of the urachus. J Urol 2000; 163:903-904.[Medline]
-
Cornil C, Reynolds CT, Kickham CJE. Carcinoma of the urachus. J Urol 1967; 98:93-95.[Medline]
-
Rubin JP, Kasznica JM, Davis CA, III, Carpinito GA, Hirsch EF. Transitional cell carcinoma in a urachal cyst. J Urol 1999; 162:1687-1688.[Medline]
-
Defabiani N, Iselin CE, Khan HG, Pache JC, Rohner S. Benign teratoma of the urachus. Br J Urol 1998; 81:760-761.[Medline]
-
Yokoyama S, Hayashida Y, Nagahama J, et al. Rhabdomyosarcoma of the urachus: a case report. Acta Cytol 1997; 41:1293-1298.[Medline]
-
Clapuyt P, Saint-Martin C, De Batselier P, Brichard B, Wese FX, Gosseye S. Urachal neuroblastoma: first case report. Pediatr Radiol 1999; 29:320-321.[Medline]
-
Sheldon CA, Clayman RV, Gonzalez R, Williams RD, Fraley EE. Malignant urachal lesions. J Urol 1984; 131:1-8.[Medline]
-
Henly DR, Farrow GW, Zincke H. Urachal cancer: role of conservative surgery. Urology 1993; 42:635-639.[Medline]
-
Paul AB, Hunt CR, Harney JM, Jenkins JPR, McMahon RFT. Stage 0 mucinous adenocarcinoma in situ of the urachus. J Clin Pathol 1998; 51:483-484.[Abstract]
-
Wong-You-Cheong JJ, Krebs TL, Daly B, et al. General case of the day. RadioGraphics 1998; 18:1614-1616.[Medline]
-
Cooperman LR. Carcinoma of the urachus with extensive abdominal calcification. Urology 1978; 12:614-616.[Medline]
-
McAfee JG, Cooley RN. Differential diagnosis of calcification encountered in abdominal radiographs. Am J Med Sci 1962; 243:609-650.
-
Nesbitt JA, Walther PJ. Computed tomographic imaging of microscopic dystrophic calcification in urachal adenocarcinoma. Urology 1986; 27:184-186.[Medline]
-
Korobkin M, Cambier L, Drake J. Computed tomography of urachal carcinoma. J Comput Assist Tomogr 1988; 12:981-987.[Medline]
-
Narumi Y, Sato T, Kuriyama K, et al. Vesical dome tumors: significance of extravesical extension on CT. Radiology 1988; 169:383-385.[Abstract/Free Full Text]
-
Brick SH, Friedman AC, Pollack HM, et al. Urachal carcinoma: CT findings. Radiology 1988; 169:383-385.
-
Lee SH, Kitchens HH, Kim BS. Adenocarcinoma of the urachus: CT findings. J Comput Assist Tomogr 1990; 14:232-235.[Medline]
-
Santucci RA, True LD, Lange PH. Is partial cystectomy the treatment of choice for mucinous adenocarcinoma of the urachus?. Urology 1997; 49:536-540.[Medline]
Top
History
Imaging Findings
