Kidney and Lower Urinary Tract

What is the renal capsule?

Thin fibrous layer overlaying cortex

May adhere to perinephric fat with tumor invasion

Why is the renal capsule important during gross examination?

It’s relationship to tumor

• Tumor may invade through the capsule and into surrounding perinephric tissue

What is the orientation of the renal cortex and medulla?

Cortex extends inward as renal columns

Medulla forms renal pyramids that terminate at papillae → Minor calyces

Why is the renal sinus an important area when evaluating a renal tumor?

Due to lack of capsule, it is an important pathway for tumor extension and spread

What is the renal sinus?

Fat-filled space between pelvis mucosa and parenchyma

• No capsule here

What structures are enclosed by Gerota’s fascia?

• Kidney

• Perinephric fat

• Adrenal gland

It is typically located anterolaterally on radical nephrectomy specimens

What is the anterior-to-posterior arrangement of the hilar structures of the kidney?

Vein → Artery → Ureter

• NOTE: Tumors may distort normal anatomy

(VAU)

How can a nephrectomy specimen be oriented using the hilar structures and adrenal gland?

Renal vein — Anterior to the artery

Ureter — Extends inferiorly

Adrenal gland — Superior and slightly medial

What is typically included in a partial nephrectomy specimen?

Tumor (confined to a pole)

• Encapsulated tumor

Renal parenchyma

Renal capsule

± Perinephric fat

What is typically included in a radical nephrectomy specimen?

Kidney

Segment of ureter

Perinephric fat

Gerota’s fascia

± Adrenal gland

What is typically included in a simple nephrectomy specimen?

Kidney

Ureteric portions

(Generally removed for non-neoplastic/non-tumorous kidneys)

What is the typical gross examination for radical nephrectomy specimen?

Weigh and measure

Describe envelope

Ink margins

Hilar structures

Bivalve kidney

Measure and describe tumor

Sample margins and interfaces

What should be documented when examining the outer envelope of a radical nephrectomy?

Presence/absence of perinephric fat

Presence/absence of Gerota's fascia

Presence/absence of adrenal gland

Any defects or disruptions of the specimen envelope

What surfaces should be inked in a radical nephrectomy containing a tumor?

Perinephric fat overlying the tumor

Gerota’s fascia near the tumor

(Ink outer surface and bivalve (section along ureter and into kidney if TCC))

How should the hilar structures be handled in a radical nephrectomy?

Measure the length and diameter of the:

• Renal vein

• Renal artery

• Ureter

Take cross-sections of each margin

What measurements should be obtained for a radical nephrectomy specimen?

Weight of the entire specimen

Overall specimen dimensions

Dimensions of the kidney proper

Measurements of associated structures when present, such as the adrenal gland and hilar structures

Why is the ureter probed before bivalving a kidney?

Helps guide sectioning along the collecting system

• Allows exposure of the collecting system and tumor–renal sinus interface

Allows bivalve specimen if fixing overnight

What tumor features should be documented in a renal tumor?

Size in 3D

• IMPORTANT FOR STAGING THRESHOLD

Location

Color/Appearance

Percentage of necrosis

Hemorrhage

Cystic change

What important tumor interfaces should be sampled in a radical nephrectomy?

Sample tumor in relation to:

• Renal capsule

• Renal sinus fat

• Renal vein

• Renal pelvis

• Renal parenchyma

Also sample uninvolved parenchyma and adrenal gland when present

What are the most important structures to evaluate for extension of a renal tumor (radical nephrectomy specimen)?

Evaluate involvement of:

• Renal sinus

• Capsule

• Perirenal fat

• Gerota's fascia

• Calyces

• Renal vein and its branches

• Inferior vena cava, when applicable

After bivalving a kidney with a tumor, how should the kidney be further sectioned?

Bread-loaf the kidney at approximately 0.5 cm intervals

Section extensively to identify:

• Additional tumors

• Tumor extension into adjacent structures

What is the classic gross appearance of clear cell (conventional) RCC?

Golden-yellow

• Due to its lipid-rich nature

It may also show:

• Cystic change

• Hemorrhage

• Necrosis

• Calcification

What is the typical gross appearance of papillary RCC?

Tan-yellow to dark brown

Variegated

Often surrounded by a fibrous pseudocapsule

May show extensive necrosis

What is the typical gross appearance of chromophobe RCC?

Solitary

Well-circumscribed

Lobulated

Homogeneous pale tan to dark brown

May have central scarring

What is the typical gross appearance of collecting duct carcinoma?

Unifocal

Poorly circumscribed

Centered in the medulla

Solid

Tan-white

Firm

How is gross tumor necrosis described, and why should the percentage be documented?

Gross necrosis may appear:

• Geographic

• Yellow-white

• Soft

• Granular/friable

• Dry on the cut surface

The percentage of necrosis should be recorded because it has prognostic importance

What gross features may suggest sarcomatoid change in a renal tumor?

Solid gray-white appearance

Invasive margins

Firm, fleshy-to-fibrous cut surface

Often associated with hemorrhage and necrosis

How should a partial nephrectomy specimen be inked?

Ink the cauterized parenchymal margin one color

Ink the perinephric/Gerota's fascia surface a different color

How should a partial nephrectomy be sectioned?

Serially section the specimen perpendicular to the resection (cauterized) margin

What tumor features should be assessed in a partial nephrectomy?

Determine:

• Whether the tumor is contained within the capsule

• Tumor size + distance to each margin

• Relationship to capsule and perinephric tissue

• Features of uninvolved renal parenchyma and corticomedullary junction

What should be submitted from a partial nephrectomy with tumor?

Submit sections demonstrating:

• Tumor to all margins

• Tumor to capsule

• Tumor to perinephric fat/fascia

• Representative uninvolved renal parenchyma

What type of specimen is this cross section?

Partial nephrectomy

What is missing from this partial nephrectomy?

No perinephric fat attached

• MAKE NOTE OF THAT IN DICTATION

How is Wilms tumor grossed differently from RCC?

Wilms tumor is grossed generally like an RCC

• An important additional step is mapping the tumor

Its staging system is also NOT TNM-based

What ancillary studies may be requested for Wilms tumor?

Depending on available tissue:

• Snap freezing for molecular studies

• Cytogenetics

• FISH (formalin fixed paraffin sections)

• IHC, including markers such as:

  • p53

  • WT1

  • CD56

What is this?

Wilms tumor

What is this?

Adult polycystic kidney disease

What is this?

Pediatric polycystic kidney disease (autosomal recessive)

What is meant by the continuous urothelial unit?

The urothelial-lined system extends continuously from the minor calyces to the ureterovesical junction (UVJ)

What are the major wall layers of the upper urinary tract?

1. Urothelium

2. Lamina propria

3. Muscularis propria

The walls of minor calyces overlying the papillae are particularly thin

Should be sampled generously to avoid overstaging

What are the approximate dimensions of the ureter?

~30 cm long

~0.5 cm in diameter

What is the bladder cuff in a nephroureterectomy specimen?

The distal-most ureter at the ureterovesical junction (UVJ)
Is included in a nephroureterectomy specimen

Why is it important to distinguish intrarenal from extrarenal renal pelvis?

Intrarenal pelvis — Surrounded by renal parenchyma

• pT3 invasion involves renal parenchyma

Extrarenal pelvis — Surrounded by peripelvic fat

• pT3 invasion involves peripelvic fat

What are the regional LNs associated with the renal pelvis?

Renal hilar

Paracaval

Para-aortic

Retroperitoneal

What are the regional LNs associated with the ureters

Renal hilar

Paracaval

Iliac (common/internal/external)

Periureteral

Pelvic

What gross appearance is typical of an upper tract urothelial carcinoma?

Soft

Friable

Gray-pink

Glistening or granular

Polypoid, papillary, or sessile

What gross appearance is typical of more invasive upper tract urothelial carcinoma?

Tend to be:

• Firm

• Solid

• Infiltrative

May cause stricture, hydroureter, or hydronephrosis

(NOT soft or friable anymore)

What should be measured in a ureterectomy specimen?

Length and diameter

Also document:

• Disruption

• Dilatation

• Visible tumor

What is the typical gross examination for ureterectomy specimen?

Measure

Ink periureteral surface

Palpate for tumor

Section around tumor

Measure invasion depth

Assess uninvolved urothelium

How should the external surface of a ureterectomy specimen be inked?

Ink the periureteral surface

• The proximal, middle, and distal thirds → Use three colors to preserve orientation

How should a ureter with a tumor be sectioned?

Serially cross-section through the tumor

Open the remaining ureter longitudinally with scissors

• Avoid cutting directly through the tumor when opening the uninvolved portion

What tumor measurements should be recorded for a ureteral tumor?

3-dimensional size when possible

• Or 2 dimensions plus depth if flattened

Depth of invasion

Distance to the inked margin

What additional findings should be evaluated in the uninvolved ureter?

Additional lesions

Hemorrhage

Discoloration

Dilatation/Stenosis

What is the typical gross examination for radical nephroureterectomy with bladder cuff specimen?

Weigh and measure

Bladder cuff

Ink margins

Bivalve kidney

Localize tumor

Assess invasion depth

Document extension

Sample uninvolved tissue

What structures and measurements should be documented in a radical nephroureterectomy with bladder cuff?

Entire specimen weight and 3D dimensions

Kidney proper

Ureter length and diameter

Renal vein and artery

Bladder cuff dimensions

How should the bladder cuff be handled?

Measured in 3 dimensions

Inked

Amputated if the tumor is not adjacent

Radially sectioned from the ureteral orifice

Submitted entirely

What margins or surfaces are inked in a radical nephroureterectomy?

Hilar soft tissue

Periureteral soft tissue

Bladder cuff

(cross-section hilar vascular margins)

How should the kidney be opened in a radical nephroureterectomy with a pelvic tumor?

Bivalve from the lateral/convex surface through the pelvis toward the hilum

• Keep the hilum intact

Adequate fixation is important because pelvic tumors may be friable

What tumor information should be documented for an upper tract urothelial carcinoma?

Location: calyces, renal pelvis, UPJ, or ureter

Unifocal vs multifocal

Size in 3 dimensions

Depth of invasion

Extension into adjacent structures

Why should the tumor-to-wall interface be sampled extensively in upper tract tumors?

Portions of the upper urinary tract can make depth of invasion difficult to assess

• Especially the thin subepithelial areas overlying papillae

Thorough sampling helps avoid overstaging or understaging

What sites of extension should be evaluated in a renal pelvis/ureter tumor?

Pelvic wall

Hilar/peripelvic fat

Renal parenchyma

Renal sinus fat

Ureter

Capsule/perinephric fat

Gerota's fascia

Adrenal gland

What uninvolved tissues should be sampled in a radical nephroureterectomy?

Pelvic and ureteral urothelium

Renal parenchyma with corticomedullary junction

Adrenal gland

Hilar lymph nodes, if present

What are the layers of the urinary bladder wall?

1. Urothelium (stratified “transitional” epithelium)

   • 3 layers when distended; 5-7 when relaxed

2. Lamina propria

3. Muscularis propria (detrusor muscle)

4. Serosa or adventitia, depending on location

   • Serosa → Dome

   • Adventitia → Remainder

(inner to outer)

What is the difference between bladder serosa and adventitia?

Serosa — Covers only the bladder dome and is continuous with the peritoneum

• NOTE: Perivesical fat is the true surgical margin, NOT serosa

Elsewhere, the bladder has adventitia

What is the muscularis propria of the bladder?

Detrusor muscle

Consists of three smooth muscle layers:

• Inner longitudinal

• Middle circular

• Outer longitudinal

Why is identifying muscularis propria important in bladder tumor specimens?

Relationship of tumor to the bladder wall and depth of invasion into or through the muscularis propria is critical to pathologic assessment and staging

What is the typical gross examination for bladder specimen?

Size (including ureters, prostate etc…)

Probe ureters and ink margins

Fill with formalin and fix if possible

Open anteriorly with a Y-shaped cut (scissors work well) avoiding mass

Measure mass, report location and distance from margins (need closest at least)

Section and report depth/structures involved

Open ureters longitudinally to look for lesions

How should a bladder biopsy be grossed?

Measure the aggregate tissue in 3 dimensions

Submit the specimen entirely

How should a TURBT specimen be grossed?

Weigh and measure aggregate fragments in 3 dimensions

Fragments are often pink-tan and cauterized, with or without blood

Submit the specimen entirely

What is TURBT?

Transurethral Resection of Bladder Tumor

What is the gross appearance of papillary urothelial carcinoma?

• Large

• Exophytic

• Friable mass

Pattern is usually low grade and arises from hyperplasia

What is the gross appearance of flat urothelial carcinoma/CIS-associated lesions?

• Hemorrhagic

• Granular

• Flattened areas

These contrast with the normal mucosal folds and arise from dysplasia/CIS

Associated pattern with higher-grade disease

What gross appearance may be seen in a cystectomy after a prior TURBT?

Rather than a discrete mass, there may be a flat, granular tumor bed or biopsy site

When is a partial cystectomies commonly used for?

Used for bladder dome tumors

What is the typical gross examination for partial cystectomy specimen?

Measure specimen (3D)

Note serosal integrity/attached perivesical ST

Any orientation markers?

Ink transmural resection margin

Section through mass

Measure tumor distance to adjacent structures

Describe remaining mucosa/average wall thickness

How should a partial cystectomy specimen be oriented?

Look for surgeon-placed orienting sutures

• Many partial cystectomy specimens have no inherent orientation

What margin is inked in a partial cystectomy?

Ink the transmural resection margin:

• One color if unoriented

• Multiple colors if orientation is provided

What should be assessed when sectioning through a bladder tumor in a partial cystectomy?

Third dimension of the tumor

Depth of invasion into or through muscularis propria

Distance to serosa

Distance to perivesical margin

Distance to the transmural excision margin

How can a radical cystectomy specimen be oriented?

Identify the ureters entering posterolaterally

Assess the integrity and amount of perivesical soft tissue/fat

What measurements should be obtained for a radical cystectomy?

Measure:

• Bladder in 3 dimensions

• Urethra in 2 dimensions

• Ureters in 2 dimensions

How should a radical cystectomy be opened?

Cut anteriorly through the urethra and into the bladder

Extend the cuts right and left in a Y-shaped fashion

• Reflect anterior wall upwards

Avoid cutting through the tumor

What should be documented for a bladder tumor in a radical cystectomy?

Location

Size

Gross appearance

Depth of invasion into or through muscularis propria

Distance to perivesical soft tissue margin

Distance to urethral margin

Distance to each ureteral margin

How are ureteral margins handled in a radical cystectomy?

The ureteral margins are shaved and submitted separately

• The ureters are opened longitudinally to evaluate for additional lesions

Where should lymph nodes be searched for in a radical cystectomy?

The perivesical fat should be sectioned and examined for lymph nodes

What additional structures are present in a cystoprostatectomy compared with a radical cystectomy?

In addition to the radical cystectomy specimen, a cystoprostatectomy includes:

• Prostate

• Seminal vesicles

• Vas deferentia

What is the typical gross examination of a cystoprostatectomy specimen?

Identify and ink

• Prostate (R/L), anterior staple margin, bladder margins (A/P)

Serially section prostate

Seminal vesicles and vas deferens?

Assess prostatic invasion

Apex margin

Incidental findings

How should the prostate be sectioned in a cystoprostatectomy according to the lecture?

Serially section the prostate from:

• Posterior aspect

• Base to apex

At approximately 5 mm intervals

What important distinction must be made when assessing prostatic involvement by bladder carcinoma?

Distinguish

• Transmural invasion into prostatic stroma

from

• Transurethral mucosal spread

How should the apical prostate margin be handled?

Shave the apical prostate margin

Bisect it into right and left portions

Section it perpendicularly

Submit it entirely

What margins from the seminal vesicles and vas deferens should be submitted?

Submit base of the:

• Seminal vesicles

• Vas deferens

margins en face

What is the key principle when selecting sections from a genitourinary tumor specimen?

Representative sections should demonstrate:

• Tumor

• Maximum depth of invasion

• Tumor-to-margin relationship

• Tumor-to-important anatomic interfaces

• Uninvolved tissue

• Adjacent structures

• Lymph nodes, when present

What are the most important interfaces to demonstrate in a renal tumor?

Sample tumor in relation to:

• Renal capsule

• Renal sinus fat

• Renal vein

• Renal pelvis

• Renal parenchyma

• Perinephric fat

• Gerota's fascia

• Adrenal gland

(Depending on the specimen)

What are the important margins in bladder cancer specimens?

Ureteral margins

Distal urethral margin

Deep/perivesical soft tissue margin

Transmural excision margin in partial cystectomy

Distance of carcinoma from the closest margin when margins are uninvolved

(Depending on the procedure)

What should always be included when documenting a urinary tract tumor grossly?

When documenting a UTT, one should include:

• Tumor location + size

• Gross appearance

• Focality, when relevant

• Depth/extent of invasion

• Relationship to adjacent structures

• Relationship to surgical margins

• Presence and extent of necrosis or other significant changes when applicable

(At the minimum)

What is the key pathway for renal tumor spread between the pelvis mucosa and renal parenchyma?

The renal sinus

• It is fat-filled and lacks a capsule

What are the list of bladder regions that should be selected if applicable tumor sites?

Trigone

R. lateral wall

L. lateral wall

Anterior wall

Posterior wall

Dome

Other (specify)

Not specified

What surrounds the abdominal vs the distal ureter?

Abdominal → Adventitia (Gerota’s fascia)

Distal → Pelvic fat

What are the two growth patterns of urothelial carcinoma?

Papillary

Flat

How should an intact radical cystectomy vs a pre-opened radical cystectomy be fixed?

Intact → Perfuse w/ formalin overnight via urethra

Pre-opened → Pin out on paraffin/cork board, fix overnight