Bladder - Adenocarcinoma-Urachal

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Bladder

Other carcinomas

Adenocarcinoma-Urachal

Reviewers: Rugvedita Parakh, M.D., HCG Oncology (see Reviewers page)
Revised: 19 June 2011, last major update June 2011
Copyright: (c) 2003-2011, PathologyOutlines.com, Inc.

Definition
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Criteria for urachal origin of adenocarcinoma:
● Centered in anterior wall or dome of bladder
● Predominant invasion of muscularis or deeper tissues with sharp demarcation between tumor and surface bladder urothelium
● Surface urothelium is free of glandular or polypoid proliferation (i.e. invasion is from outside in)
● No carcinoma in situ or glandular metaplasia other than (possibly) cystitis glandularis is present
● The presence of urachal remnants is helpful but not always identifiable
● No primary adenocarcinoma elsewhere

● Represents 10-30% of bladder adenocarcinomas, 0.3% of all bladder cancers

Epidemiology
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● Mean age 52 years but wide age range; no gender preference

Sites
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● Usually dome of bladder; occasionally anterior wall of bladder

Etiology
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● The urachus is the embryological remnant of the urogenital sinus and allantois, connecting the bladder to the umbilicus; involution usually happens before birth and the urachus becomes a fibrous cord known as the median umbilical ligament, which is not part of the adult bladder
● Remnants of the allantois may persist and develop into cysts or epithelial neoplasms
● Urachus - drawing

Clinical features
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● Staging may be difficult, since arises in bladder wall
● 40-50% recur locally
● Metastasizes to lymph nodes, lungs, peritoneal cavity, liver and bone
● Compared to non-urachal adenocarcinoma, patients/tumors are slightly younger (median age 56 vs. 69 years), less likely high grade (35% vs. 66%), distant metastases are more common (30% vs. 15%), but better survival (Cancer 2006;107:721)

Sheldon staging system:
● pT1-no invasion beyond the urachal mucosa (i.e. in situ)
● pT2-invasion confined to the urachus
● pT3-local extension to the (a) bladder, (b) abdominal wall, and (c) viscera other than the bladder
● pT4-metastasis to (a) regional lymph nodes and (b) distant sites
References: (J Urol 1984;131:1)

Prognostic factors
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● Poor prognosis (5 year survival of 50%) since diagnosed late in course of disease due to growth in a clinically silent space (between bladder and umbilicus)
● Prognostic factors are tumor stage and histologic differentiation (Hum Pathol 1996;27:240)

Case reports
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● 30 year old woman with vertebral metastasis (Arch Pathol Lab Med 2004;128:1043)
● 45 year old man with 11 cm tumor (World J Surg Oncol 2009 Nov 7;7:82)
● 54 year old man with in situ adenocarcinoma of the urachus arising in a giant urachal cyst, and associated pseudomyxoma peritonei (J Clin Pathol 2003;56:152)
● 55 year old man with enteric type tumor (Can J Urol 2009;16:4753)
● 55 year old man with mucinous colloid adenocarcinoma of urachus (RadioGraphics 2001;21:965)
● 58 year old man with mucinous urachal cystadenocarcinoma and pseudomyxoma peritonei (Magn Reson Med Sci 2009;8:85)
● Signet-ring cell type with linitis plastica growth (Arch Pathol Lab Med 1981;105:203)

Treatment
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● Umbilectomy with partial cystectomy, possibly laparoscopic (Clinics (Sao Paulo) 2008;63:731)
● Must excise entire tract of median umbilical ligament

Clinical images
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Axial CT image shows a large, predominantly solid, midline mass with peripheral calcifications (arrowheads); within the mass are scattered low-attenuation areas (arrows), which represent mucin

Cystoscopy demonstrates an area of ulceration at the bladder dome (arrow) in a background of normal pink bladder mucosa

Intraoperative image of suprapubic mass

Intraoperative image of cystic lesion at dome of bladder

Intraoperative image of urachal cyst

Intraoperative image of multilobulated cyst

Gross description
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● Arises in dome of bladder or anterior bladder or beneath anterior abdominal wall between umbilicus and bladder dome
● Tumor may occur anywhere along urachal tract

Gross images
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Tumor removed en bloc with umbilicus, lateral umbilical ligaments, adjacent peritoneum and bladder dome

Surgical resection extended from bladder dome mass (arrowheads) to umbilicus (arrow)

Polypoid ulcerated mass

Cystic mass with hemostat on umbilicus (arrow)

White mucinous center (black arrow) of cystic component; dome of the bladder is indicated by white arrow

Cut surface shows a glistening surface

Cut surface shows a large intramural mucinous mass

Tumor contains white gelatinous material

Micro description
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● Epicenter is in bladder wall
● Tumor is sharply demarcated from normal epithelium
● Most tumors arise from intramural portion of urachus, grow into bladder wall, may lack mucosal involvement
● Usually well-differentiated, mucin-producing adenocarcinomas
● Often enteric type; also colloid type (tumor cells float in mucin lakes), features of lymphoepithelioma-like carcinoma, urothelial carcinoma, signet-ring cell carcinoma
● Often NO intestinal metaplasia

Micro images
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Colloid type adenocarcinoma; mucin and tumor cells dissect through muscularis propria

Adenocarcinoma involves bladder wall with large lakes of mucin (arrows); bladder mucosa (arrowhead) is normal

Signet-ring and colloid components

Mucinous cystadenocarcinoma with invasion and mucin extravasation

Tumor extends to umbilicus

Papillary and glandular patterns

Moderately differentiated tumor in muscularis propria

Vertebral metastasis of above tumor

Complex mucin-secreting epithelium (black arrow)

Tall simple to pseudostratified columnar epithelium, including goblet cells

May resemble colonic adenocarcinoma

Mucin production and intestinal-like epithelium

Tumor has variable staining for CDX2, and is CK7+, CK20+

In situ tumor with no evidence of invasion

Videos
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55 year old man with robotic surgery

Positive stains
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● CK7; variable CK20 and CDX2 (Am J Surg Pathol 2011;35:787)

Differential diagnosis
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● Local extension of colonic or other adenocarcinoma: clinical history is important; diffuse positivity for 34BE12 supports urachal carcinoma, diffuse nuclear immunoreactivity for beta-catenin suggests not urachal carcinoma (Am J Surg Pathol 2009;33:659)
● Metastatic adenocarcinoma: clinical history is important
● Nonurachal adenocarcinoma of bladder: intraluminal mass, carcinoma in situ or extensive glandular metaplasia of adjacent urothelium
● Villous adenoma: noninvasive

End of Bladder > Other carcinomas > Adenocarcinoma-Urachal

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