Bladder, ureter & renal pelvis
General
Staging-bladder carcinoma
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Last author update: 13 January 2021
Last staff update: 2 February 2021
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Cite this page: Zynger DL. Staging-bladder carcinoma. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/bladderstaging.html. Accessed March 26th, 2023.
Definition / general
- All carcinomas of the bladder are covered by this staging system
- These topics are not covered: urachal carcinoma, paraganglioma, sarcoma or lymphoma
Essential features
- AJCC 7th edition staging was sunset on December 31, 2017; as of January 1, 2018, use of the 8th edition is mandatory
Primary tumor (pT)
- pTX: cannot be assessed
- pT0: no evidence of primary tumor
- pTa: noninvasive papillary carcinoma
- pTis: carcinoma in situ
- pT1: invades lamina propria
- pT2a: invades inner half of muscularis propria
- pT2b: invades outer half of muscularis propria
- pT3a: microscopically invades perivesical tissue
- pT3b: macroscopically invades perivesical tissue
- pT4a: directly invades prostatic stroma, seminal vesicles, uterus or vagina
- pT4b: directly invades pelvic wall or abdominal wall
Lamina propria (pT1):
- Lamina propria contains connective tissues between urothelium and detrusor muscle (muscularis propria), made of loose stroma, variably sized blood vessels and thin muscle bands of muscularis mucosae
- Has nests, clusters or single tumor cells, sometimes with prominent retraction artifact (mimics lymphovascular invasion)
- Often has desmoplastic or inflammatory stromal response and absent or irregular basement membrane (not seen with noninvasive low grade papillary carcinoma with inverted pattern)
- Tumor cells often have abundant eosinophilic cytoplasm at advancing edge ("paradoxical differentiation")
- If tumor cells hug the mucosa, they should be more anaplastic than benign mucosal cells
- Pitfalls include tangential sectioning, poor specimen orientation, inflammation, thermal injury, deceptively bland cytology and pseudoinvasive nests of benign proliferative urothelial cells (Pathology 2003;35:484)
- Substaging of pT1 based on muscularis mucosae is technically difficult and not reproducible (Mod Pathol 1996;9:1035)
- Hyperplastic muscular mucosa may resemble muscularis propria (Am J Surg Pathol 2007;31:1420)
- pTa cases may actually be invasive when studied by electron microscopy; significance unclear (Am J Clin Pathol 2003;120:188)
- Invasion of lamina propria can be subjective and is not as clinically crucial as invasion of muscularis propria (pT2)
- 50% recur
Muscularis propria (pT2):
- Muscularis propria is thick aggregated muscle bundles of detrusor muscle; must distinguish from hypertrophic muscularis mucosae
- Muscularis propria invasion prompts definitive therapy, typically cystectomy with or without neoadjuvant therapy
- Muscularis propria presence should be specified in transurethral resections and cold cup biopsies
- Difficult to substage as pT2a or pT2b unless pathologist has full thickness bladder wall and well oriented section
- Can use muscle markers such as desmin or SMA to highlight muscle and keratins, such as AE1 / AE3 to highlight carcinoma
Perivesical fat (pT3):
- Perivesical adipose tissue is deep to muscularis propria but is also present within deep lamina propria, usually as small localized aggregates and within muscularis propria (superficial and deep)
- Beware of inappropriate staging as pT3 due to tumor infiltration of adipose tissue, particularly in TURBT specimens (Am J Surg Pathol 2000;24:1286)
Prostate gland (pT4 versus pT2):
- If carcinoma of the bladder transmurally invades through the bladder wall and into the prostatic stroma, the tumor is designated as pT4a
- If carcinoma of the bladder colonizes the prostatic urethra
via in situ spread and then invades the underlying prostatic stroma, it is not pT4a (but can be considered a separate tumor of the prostatic urethra with a pT2 designation, see staging of the prostatic urethra)
Regional lymph nodes (pN)
- pNX: cannot be assessed
- pN0: no regional lymph node metastasis
- pN1: metastasis in 1 true pelvic lymph node
- pN2: metastasis in greater than 1 true pelvic lymph node
- pN3: metastasis in common iliac lymph node
Notes:
- Regional lymph nodes are the true pelvic lymph nodes which include the following:
- Perivesical
- Hypogastric / deep obturator / fossa of Marcille / internal iliac
- Obturator
- External iliac
- Presacral / sacral / lateral sacral / sacral promontory
Prefixes
- y: preoperative radiotherapy or chemotherapy
- r: recurrent tumor stage
AJCC prognostic stage groups
| Stage group 0a: | Ta | N0 | M0
|
| Stage group 0is: | Tis | N0 | M0
|
| Stage group I: | T1 | N0 | M0
|
| Stage group II: | T2a - 2b | N0 | M0
|
| Stage group IIIA: | T3a - 4a | N0 | M0
|
| T1 - 4a | N1 | M0
|
| Stage group IIIB: | T1 - 4a | N2 - 3 | M0
|
| Stage group IVA: | T4b | any N | M0
|
| any T | any N | M1a
|
| Stage group IVB: | any T | any N | M1b
|
Registry data collection variables
- Extranodal extension
- Number of lymph nodes examined and number positive
- Grade
- Lymphovascular invasion
- Concurrent pTa with pTis
Histologic grade (G)
- Urothelial carcinoma
- LG: low grade
- HG: high grade
- Squamous cell carcinoma and adenocarcinoma
- GX: cannot be assessed
- G1: well differentiated
- G2: moderately differentiated
- G3: poorly differentiated
Notes:
- Clinical management with respect to intravesicular BCG / chemotherapy and frequency of surveillance differs for high grade versus low grade tumors
Histopathologic type
- Noninvasive low grade papillary urothelial carcinoma
- Noninvasive high grade papillary urothelial carcinoma
- Urothelial carcinoma in situ
- Invasive urothelial carcinoma
- Invasive urothelial carcinoma variants
- Squamous
- Glandular
- Nested
- Microcystic
- Micropapillary
- Lymphoepithelioma-like
- Plasmacytoid
- Giant cell
- Lipid rich
- Clear cell
- Sarcomatoid
- Squamous cell carcinoma
- Adenocarcinoma
- Small cell neuroendocrine carcinoma
Gross images
Contributed by Debra L. Zynger, M.D.
Muscularis propria invasion (pT2b)
Prostatic invasion (pT4a)
Microscopic (histologic) images
Contributed by Debra L. Zynger, M.D.
Noninvasive low grade (pTa)
Microinvasion (pT1)
Lamina propria invasion (pT1)
Within muscularis mucosae (pT1)
Within muscularis propria (pT2)
Within perivesicular adipose (pT3)
Lung metastasis (pM1b)
Uterus metastasis (pM1b)
Common iliac lymph node metastasis (pN3)
Board review style question #1
Invasion of which structure typically is treated with cystectomy?
- Urothelium
- Lamina propria
- Muscularis mucosae
- Muscularis propria
Board review style answer #1
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