Bladder adenocarcinoma is a rare malignant tumor of the bladder mucosa showing glandular differentiation, accounting for 0.5-2% of all bladder cancers. It has two main subtypes: urachal (dome origin, 30-40%) and non-urachal (trigone/base origin, 60-70%). Urachal adenocarcinoma arises from urachal remnants and presents as a midline mass between the bladder dome and umbilicus — this location is pathognomonic. The non-urachal type develops in the setting of chronic irritation (schistosomiasis, bladder exstrophy, intestinal metaplasia). Mucinous histology predominates and mucin production is reflected in imaging as low attenuation/high T2 signal. Mean age at diagnosis is 55-65 years. Usually advanced stage at diagnosis. Prognosis varies by histological subtype but is generally worse than urothelial carcinoma. Standard chemotherapy regimens differ from urothelial carcinoma — 5-FU-based regimens may be preferred.
Age Range
40-75
Peak Age
55
Gender
Male predominant
Prevalence
Bladder adenocarcinoma develops through two distinct pathogenetic pathways. The urachal type arises from glandular epithelial cells in remnants of the urachus (median umbilical ligament) that connected the allantois and bladder dome during fetal development. The urachus normally obliterates after birth but glandular remnants may persist — malignant transformation in these remnants produces urachal adenocarcinoma. The tumor begins extramucosal on the bladder dome and can grow into the lumen while also extending toward the umbilicus between dome and navel. Mucin production is characteristic — mucin (glycoprotein) shows low attenuation (10-30 HU) on CT and very high signal on MRI T2 due to high water content. Peripheral calcification (50-70%) results from dystrophic calcium deposition around the tumor. The non-urachal type develops in the setting of intestinal metaplasia due to chronic irritation — glandular structures form and adenocarcinoma transformation occurs. Enhancement varies depending on the proportion of solid and mucinous components: solid areas enhance while mucinous areas do not.
Midline mass or soft tissue tract extending from the bladder dome toward the umbilicus. Pathognomonic for urachal adenocarcinoma and a key component of Sheldon criteria. The tumor grows along the urachal remnant and can be traced beneath the anterior abdominal wall/peritoneum. This finding is the most reliable criterion distinguishing urachal-origin adenocarcinoma from any other bladder malignancy.
Heterogeneous density mass at midline location on the bladder dome on non-contrast CT. Mucinous component shows low attenuation (10-30 HU) while solid component is at soft tissue density. Calcification within or around the tumor is detected in 50-70% of cases — peripheral/curvilinear pattern or focal coarse calcification. The mass may extend into prevesical fat (space of Retzius) and may show midline extension toward the umbilicus.
Report Sentence
A heterogeneous density mass measuring approximately ___ mm at midline location on the bladder dome is seen on non-contrast CT, with mucinous component (low attenuation) and peripheral calcification; urachal adenocarcinoma should be the primary consideration.
The solid component within the mass shows enhancement on portal venous phase while the mucinous component does not enhance. This creates a heterogeneous enhancement pattern — solid septa or nodules enhance while mucinous areas remain low attenuation. The mass may extend from the bladder dome into prevesical fat and toward the umbilicus. Peritoneal implants and pelvic lymphadenopathy may accompany in advanced stage.
Report Sentence
The solid components of the bladder dome mass show enhancement on portal venous phase while mucinous areas remain low attenuation; the mass ___ (extends/does not extend) into prevesical fat.
Very high signal intensity mass at midline location on the bladder dome on T2W MRI, due to mucinous component. Mucinous areas show very high T2 signal similar to simple fluid. Solid component appears as intermediate signal septa or wall thickening. On T1W, the mucinous component shows variable signal — low-to-intermediate signal depending on protein/mucin concentration. Calcification appears as signal void on T2.
Report Sentence
A mass measuring approximately ___ mm at midline location on the bladder dome is seen on T2W MRI, containing mucinous component (very high T2 signal) and solid component (intermediate signal); urachal adenocarcinoma should be considered.
Solid components of the mass show diffusion restriction on DWI (high signal, low ADC). Mucinous component may show variable signal on DWI — viscous mucin may restrict diffusion (false positive due to T2 shine-through effect). Confirmation with ADC map is critical. Diffusion restriction in the solid component reflects tumor cellularity and supports malignancy.
Report Sentence
Solid components of the mass show diffusion restriction on DWI (ADC: low), while mucinous areas show high signal due to T2 shine-through effect.
Mixed-echogenicity mass on the bladder dome on US. Mucinous component is anechoic or low echogenicity, solid component is hyperechoic, calcification areas show strong echogenicity + acoustic shadowing. Mass may show intramural and/or intraluminal extension. Extension into prevesical fat can be evaluated with transabdominal US but dome location may create difficulty for optimal assessment.
Report Sentence
A mixed-echogenicity mass measuring approximately ___ mm on the bladder dome is seen on US, with cystic/mucinous areas and calcification; urachal adenocarcinoma should be considered.
Midline soft tissue extension from the bladder dome toward the umbilicus along the median umbilical ligament on delayed phase. This finding is pathognomonic for urachal adenocarcinoma and is a key component of Sheldon criteria. Extension is traced beneath the anterior abdominal wall and behind the peritoneum. Calcified and/or mucinous component may also be seen along this tract.
Report Sentence
Midline soft tissue extension from the bladder dome mass toward the umbilicus along the median umbilical ligament is seen, consistent with urachal adenocarcinoma.
Criteria
Adenocarcinoma arising from urachal remnants. Sheldon criteria: (1) dome location, (2) bulk of tumor in/through bladder wall, (3) absence of urothelial cystitis glandularis, (4) extension in prevesical fat. Comprises 30-40% of all bladder adenocarcinomas.
Distinct Features
Midline dome location, extension toward umbilicus, mucinous content (70%+), peripheral calcification (50-70%), early prevesical fat invasion. Mucinous pseudomyxoma peritonei complication possible. Surgery: partial cystectomy + en-bloc urachus excision + umbilectomy.
Criteria
Adenocarcinoma developing from glandular metaplasia of bladder urothelial mucosa. Diagnosed when urachal origin is excluded. Associated with chronic irritation (schistosomiasis, exstrophy, intestinal metaplasia).
Distinct Features
Non-dome location (trigone, lateral wall), no midline extension, variable mucinous content, calcification less common. Radical cystectomy is standard treatment. Prognosis worse than urachal type.
Criteria
Histological subtype with >50% extracellular mucin pools. Can be seen in both urachal and non-urachal types.
Distinct Features
Prominent low-attenuation areas on CT, very high signal on T2 MRI, minimal enhancement (sparse solid component). Higher risk of pseudomyxoma peritonei. Better prognosis (compared to non-mucinous type).
Distinguishing Feature
Urothelial carcinoma typically presents as papillary mass on posterolateral wall while adenocarcinoma presents as midline dome mass. Calcification and mucinous content are rare in urothelial carcinoma. Location is the most important distinguishing criterion.
Distinguishing Feature
Urachal cyst appears as a well-defined, thin-walled, simple fluid-containing cystic lesion. No solid component, enhancement, or calcification (unless infected). Solid component, enhancement, and calcification in adenocarcinoma are distinguishing.
Distinguishing Feature
Bladder calculus appears as a freely mobile, homogeneous high-density intraluminal structure. No soft tissue component. Calcification in adenocarcinoma is within/around the tumor mass and accompanied by soft tissue component.
Distinguishing Feature
Bladder endometriosis occurs in young women with cyclic symptoms. High signal on T1W (hemorrhagic content), variable signal on T2 ('shading' phenomenon). Calcification is rare. Solid enhancing component is usually absent. Calcification, mucinous content, and solid component in urachal adenocarcinoma are distinguishing.
Urgency
urgentManagement
surgicalBiopsy
NeededFollow-up
specialist-referralDiagnosis of bladder adenocarcinoma is confirmed by cystoscopy + biopsy. Sheldon criteria are evaluated for the urachal type. Treatment: urachal adenocarcinoma — partial cystectomy + en-bloc urachus excision + umbilectomy; non-urachal — radical cystectomy. Chemotherapy differs from urothelial carcinoma: 5-FU-based regimens (FOLFOX, XELOX) may be preferred. Mucinous pseudomyxoma peritonei complication should be monitored. Prognosis is stage-dependent: localized urachal type 5-year survival 50-60%, non-urachal 20-30%.
Bladder adenocarcinoma is a rare but aggressive tumor. The urachal type is the most common subgroup and uses the Sheldon staging system. Surgical treatment (partial cystectomy + urachus resection or radical cystectomy) is the primary treatment. Chemotherapy response is limited — standard TCC chemotherapy (cisplatin-based) is ineffective; colorectal chemotherapy regimens (5-FU based) may be tried. 5-year survival is stage-dependent (40-60%).