Ureters Tumors and Tumor like Lesions

Slide 1 · Ureters: tumors andtumor-like lesions

Fibroepithelial polyp • papillary urothelial carcinoma • obstruction

Dr Abu Suraih Sakhri

MBBS, MD (Pathology)

www.abusuraihsakhri.com

Slide 2 · Learning outcomes

Distinguish benign fibroepithelial polyps from malignant urothelial tumors

Explain the papillary architecture of ureteral neoplasia

Connect luminal growth with hydroureter, hydronephrosis, and infection

Interpret multifocal disease across the urothelial tract

Slide 3 · A ureteral lesion exists in a continuous urothelial tract

Renal pelvis

Ureter

Urinary bladder

Proximal urethra

Shared urothelial lining links neoplastic patterns across sites

Schematic—anatomic sequence, not drawn to scale

Slide 4 · Normal urothelium: The reference point

Approximately five to six layers of epithelial cells description

Large superficial umbrella cells cap the epithelial surface

The basement membrane separates urothelium from lamina propria

A papillary mass must be evaluated for both lining cytology and supporting stroma

Slide 5 · Cross-section: Mucosa, wall, and lumen

Urothelial lining

Basement membrane

Subepithelial connective tissue / wall

Deeper wall (schematic)

Simplified conceptual cross-section—not diagnostic histology

Slide 6 · Two families of primary ureteral lesions

Tumor-like / benign

Benign primary tumors usually have mesenchymal origin

Fibroepithelial polyp is a characteristic tumor-like lesion

A lesion may obstruct despite benign biology

Malignant

Primary malignant ureteral lesions resemble tumors of pelvis and bladder

Papillary urothelial carcinoma predominates

Potential for obstruction and multilevel disease

Slide 7 · A rare tumor still requires a complete tissue diagnosis

Ureteral masses can have mesenchymal or urothelial origins

A luminal mass can be benign, malignant, or non-neoplastic obstruction

Distinguish the source compartment before labeling carcinoma

Document physiologic obstruction separately from tissue classification

Slide 8 · Benign and malignant lesions can share a presentation

Overlap

Both may produce an intraluminal mass

Both may compromise urinary drainage

A polypoid gross appearance alone is not definitive

Discriminators

Evaluate the architecture of the stromal core

Assess urothelial cytologic atypia

Determine whether invasion is present

Slide 9 · From mucosal lesion to obstructed lumen

Lesion

Upstream urine flow

Narrowed passage

Slide 10 · Diagnostic reasoning starts with the lesion compartment

First ask whether the lesion projects from the mucosal surface

Then distinguish a stromal polyp from a urothelial epithelial proliferation

Finally, evaluate cytologic grade, invasion, and accompanying lesions

Do not treat “polyp” as a synonym for “benign”

Slide 11 · Fibroepithelial polyp: The defining lesion

A tumor-like ureteral lesion, often encountered in children

Composed of loose, vascularized connective tissue

Covered by urothelial epithelium

The supporting stroma—not a malignant epithelial proliferation—defines the polyp

Slide 12 · Fibroepithelial polyp: Structural organization

Urothelial surface

Vascularized loose core

Schematic fibrovascular polyp—not an H&E photomicrograph

Slide 13 · Polyp core: What “fibroepithelial” means

“Fibro-” refers to connective-tissue support

“Epithelial” describes the urothelial surface covering

A vascularized stromal axis organizes the protruding lesion

The two components must be assessed together

Slide 14 · Low-power interpretation of a polyp

Urothelial covering

Fibrovascular stroma

Schematic polyp cross-section—not diagnostic H&E

Slide 15 · A tumor-like lesion is not automatically a carcinoma

A mass-forming lesion may reflect a benign stromal proliferation

Luminal protrusion itself does not establish malignancy

The diagnostic distinction is histologic, not just geometric

Recognize the fibroepithelial architecture before applying epithelial cancer grades

Slide 16 · Why a benign ureteral polyp can matter clinically

The ureter is a conduit: Luminal occupancy has functional consequences

An obstructing benign lesion can still impair urinary outflow

Hydroureter or hydronephrosis reflects obstruction, not necessarily cancer

Histologic biology and renal physiologic consequences must be reported separately

Slide 17 · Fibroepithelial polyp versus urothelial papilloma

Fibroepithelial polyp

Stromal lesion with loose vascularized core

Covered by urothelium

Defined chiefly by supporting mesenchymal tissue

Urothelial papilloma

A benign epithelial papillary neoplasm

Delicate fibrovascular papillae lined by normal-appearing urothelium

An epithelial neoplastic classification

Slide 18 · Fibroepithelial polyp versus papillary carcinoma

Polyp

Stroma is the primary lesion

Urothelial covering is not, by itself, evidence of cancer

Obstruction may be present without invasion

Papillary urothelial carcinoma

Neoplastic urothelial proliferation lines papillae

Nuclear atypia and architectural disorder determine grade

Assess for invasion beyond the basement membrane

Slide 19 · When a polypoid specimen is sampled

Document whether the lesion contains recognizable urothelial lining

Identify the quality and vascularity of the underlying stroma

Search for atypical epithelial growth beyond the benign lining

Avoid a definitive carcinoma classification without adequate supporting morphology

Slide 20 · Polyp differential: A structured decision

What drives the mass?

Loose vascularized stroma

Proliferating urothelium

Consider fibroepithelial polyp

Assess grade and invasion

Slide 21 · Case 1: Pediatric ureteral mass

Clinicopathologic application

A child has a polypoid ureteral lesion and impaired drainage

Sections show a loose vascularized core beneath urothelial covering

No destructive epithelial invasion is identified in the examined sections

What diagnosis best fits the described findings?

Slide 22 · Case 1: Interpretation

Most consistent morphologic diagnosis: Fibroepithelial polyp

The age and the stromal architecture are concordant with Robbins

Explain the obstruction separately from the benign classification

Evaluate the actual sampled lesion rather than relying on age alone

Slide 23 · Malignant ureteral tumors: The dominant phenotype

The majority of primary malignant ureteral tumors are papillary urothelial carcinomas

They resemble urothelial tumors in renal pelvis, calyces, and bladder

Their luminal location creates a direct route to mechanical obstruction

Concurrent tumors elsewhere in the urothelial tract are common

Slide 24 · Age distribution of ureteral malignancy

The peak frequency in the sixth and seventh decades

This is descriptive age information—not a diagnostic cutoff

A benign lesion and carcinoma can overlap by age

Let morphology adjudicate the differential

Slide 25 · Papillary carcinoma: Architecture before cytology

Finger-like luminal projections

Base of lesion

Schematic papillary architecture; Cytologic grade not depicted

Slide 26 · Papillary and flat urothelial growth

Papillary

Exophytic projections extend into the lumen

The source describes most ureteral carcinomas as papillary

Papillary form may facilitate obstruction

Flat / CIS

Cytologically malignant urothelium can remain flat

CIS may extend across urothelial sites

Flat morphology is not equivalent to benign behavior

Slide 27 · Noninvasive papillary tumor spectrum

Urothelial papilloma: Normal-appearing epithelium on delicate papillae

PUNLMP: Thicker and more cellular urothelial lining

Low-grade papillary carcinoma: Ordered architecture with mild atypia

High-grade papillary carcinoma: Marked cytologic atypia and disorder

Slide 28 · Papillary urothelial grading: Morphology

Feature

Low-grade

High-grade

Polarity

Generally maintained

Frequently disordered

Cohesion

Cohesive, orderly

May be discohesive

Nuclei

Limited variation; scattered hyperchromasia

Large, hyperchromatic; irregular chromatin

Mitoses

Infrequent, mainly basal

Often frequent, including atypical forms

Slide 29 · Low-grade papillary carcinoma: What to recognize

The epithelial architecture remains relatively orderly

Cells tend to be evenly spaced and retain polarity

Atypia is present, but less pronounced than in high-grade lesions

Histologic grade is an epithelial descriptor, not a measure of luminal obstruction

Slide 30 · High-grade papillary carcinoma: What changes

Marked nuclear hyperchromasia and irregular chromatin

Prominent nucleoli; Substantial variation in cell appearance

Mitoses may be numerous or atypical

Loss of polarity and discohesion distinguish it from an orderly papillary lesion

Slide 31 · Grade and depth are different questions

Grade

How abnormal the tumor cells and architecture appear

Low-grade versus high-grade cytology

Assessed within the urothelial epithelial proliferation

Invasion

Whether tumor has crossed the epithelial basement membrane

Extent into subjacent tissues, if present

Requires evaluation of tissue interface and sampling

Slide 32 · Noninvasive versus invasive urothelial carcinoma

Noninvasive

Invasive

Schematic: Basement membrane interface defines invasion

Slide 33 · Urothelial carcinoma in situ: A second pattern

Flat urothelium contains cytologically malignant cells

A visible papillary mass is not required for CIS

The bladder source notes that CIS can extend to ureters and urethra

Evaluate surrounding flat urothelium when relevant

Slide 34 · Why a normal-looking adjacent area may matter

Urothelial neoplasia can be multifocal

Renal pelvic cancer sections describe atypia or CIS in grossly normal remote urothelium

Macroscopic normality does not guarantee microscopic normality

This is a rationale for examining non-mass mucosa when sampled

Slide 35 · Ureteral carcinoma and renal-pelvis carcinoma overlap

Both arise in urothelial-lined upper-tract locations

Robbins explicitly compares primary ureteral malignancies to renal-pelvis cancers

Renal pelvic tumors can have associated sites of urothelial atypia

Site and extent still need careful anatomic designation

Slide 36 · Synchronous urothelial tumors: The anatomic map

Renal pelvis

Ureter

Urinary bladder

Proximal urethra

Shared urothelial lining links neoplastic patterns across sites

Schematic—anatomic sequence, not drawn to scale

Colored markers denote possible separate lesion sites, not observed tumors

Slide 37 · Multifocal urothelial disease changes the assessment

Ureteral carcinoma may coexist with lesions in the pelvis or bladder

Separate sites require separate anatomic description

A grossly normal surface may still contain atypia or in situ carcinoma

Finding one tumor does not exclude a second lesion elsewhere

Slide 38 · Cytology and shedding: Relevant background

High-grade papillary cancers and CIS may have reduced cellular cohesion

Shedding of atypical cells into urine is described for CIS

Urinary findings may therefore reflect urothelial disease at various levels

Urine cytology alone cannot specify anatomic site in this source

Slide 39 · Distinct axes of ureteral tumor description

Site: Ureteral segment and relation to renal pelvis or bladder

Architecture: Papillary, flat, or infiltrative pattern

Biology: Benign / low malignant potential / carcinoma

Extent: Confined to urothelium or infiltrating the wall

Slide 40 · Obstruction is a core consequence of ureteral carcinoma

Malignant ureteral neoplasms obstruct the lumen

A growing intraluminal mass reduces the passage available for urine

Obstruction links tumor morphology with kidney-level damage

Degree of obstruction should not be inferred from tumor grade alone

Slide 41 · Ureteral obstruction: The upstream sequence

Ureteral blockage

Narrowed lumen

Hydroureter

Upstream dilation

Hydronephrosis

Collecting-system dilation

Obstruction can also predispose to pyelonephritis

Slide 42 · Unilateral and bilateral obstruction patterns

Unilateral

Often due to a proximal intrinsic or extrinsic cause

Examples: Ureteral calculus or neoplasm

Can affect the upstream collecting system on one side

Bilateral

More often attributed to distal outflow causes

Textbook example: Nodular hyperplasia of prostate

Do not assume two ureteral primary tumors are present

Slide 43 · Intrinsic obstruction: Important alternatives

Cause

Pathologic mechanism / clue

Ureteral carcinoma

Primary intraluminal neoplastic growth

Fibroepithelial polyp

Benign mass within the lumen

Calculus

Mechanical intraluminal obstruction

Stricture

Congenital or acquired luminal narrowing

Blood clot

Possible consequence of urinary tract bleeding

Slide 44 · Extrinsic obstruction: Why a mass need not be ureteral

Cause group

Illustrative examples in Robbins

Pelvic / adjacent cancers

Rectum, bladder, prostate, ovary, uterus, cervix

Other neoplasms

Lymphoma, sarcoma

Inflammatory disease

Periureteral inflammatory processes

Fibroinflammatory disease

Sclerosing retroperitoneal fibrosis

Other conditions

Endometriosis; pregnancy

Slide 45 · Intrinsic mass versus external encasement

Intrinsic mass

External compression

Schematic compartments—no patient imaging

Slide 46 · Hydronephrosis is a consequence, not a diagnosis

Upstream collecting-system dilation may follow ureteral obstruction

A calculus, benign polyp, malignant tumor, or external process can be causal

Hydronephrosis alone cannot identify histologic tumor type

The etiologic lesion must be investigated separately

Slide 47 · Pyelonephritis as an obstructive complication

Pyelonephritis among consequences of ureteral blockage

Impaired urine flow may coexist with ascending infection

Inflammatory injury can compound the effects of urinary stasis

Obstruction and infection should be assessed as related but distinct problems

Slide 48 · Clinical presentation: Integrate site and morphology

The ureteral section explicitly emphasizes luminal obstruction

The renal-pelvis section links urothelial tumors with hematuria and flank pain

Clinical features overlap with non-neoplastic obstruction

Do not classify tumor grade from symptoms

Slide 49 · Hematuria versus obstruction: Distinct clues

Hematuria

Signals urinary tract bleeding but is not site-specific

Renal pelvic tumors are described as producing noticeable hematuria

Bleeding alone does not classify urothelial tumor grade

Obstruction

Signals impeded drainage, not necessarily carcinoma

Can cause hydroureter, hydronephrosis, or pyelonephritis

Requires intrinsic/extrinsic differential

Slide 50 · What a pathology description should resolve

Specify whether the lesion is stromal or urothelial in character

For urothelial neoplasia, describe grade where evaluable

Record evidence of invasion if the sampled tissue permits assessment

Avoid implying that insufficiently sampled wall establishes absence of invasion

Slide 51 · Sampling limitation: “not seen” versus “excluded”

A superficial fragment may show only epithelial papillae

A sample without underlying wall cannot fully assess deeper invasion

Do not equate absence of invasion in limited tissue with comprehensive staging

Interpret negative findings in relation to specimen adequacy

Slide 52 · Case 2: Papillary lesion in an older adult

Clinicopathologic application

A patient in the seventh decade has an obstructing ureteral mass

Histology reveals a papillary urothelial proliferation with marked atypia

A bladder lesion is also identified

What are the two most important diagnostic questions?

Slide 53 · Case 2: Interpretation

Evaluate papillary urothelial carcinoma and its grade

Determine whether the sampled tumor invades the ureteral wall

Assess each coexisting urothelial lesion by site

Obstruction and synchronous disease are expected considerations

Slide 54 · Case 3: Dilation with no mucosal mass

Clinicopathologic application

There is hydroureter and hydronephrosis

Examination shows periureteral encasement rather than an intraluminal tumor

Which diagnostic category should be considered before ureteral carcinoma?

Slide 55 · Case 3: Interpretation

An extrinsic obstructive process becomes more likely

Consider malignant encasement, periureteral inflammation, and fibrosis

Do not label external disease as a primary ureteral carcinoma

The pathologic lesion and its anatomic compartment determine terminology

Slide 56 · Final synthesis: A four-question framework

Question

Key discriminator

What is the lesion?

Fibroepithelial stromal polyp versus epithelial urothelial neoplasm

Is it malignant?

Urothelial cytologic features, architecture, and invasion

What does it do?

Luminal obstruction; upper-tract dilation; infection

Is disease elsewhere?

Renal pelvis and bladder may harbor coexisting lesions

Slide 57 · Essential conclusions

Primary ureteral tumors are rare; Most malignant lesions are papillary urothelial carcinomas

Fibroepithelial polyp has a loose vascularized stromal core covered by urothelium

Tumor biology, invasion, obstruction, and synchronous disease are separate assessments

Renal-pelvis and bladder pathology provide context, not ureter-specific rate estimates

Slide 58 · Core reading

Robbins, Cotran & Kumar: Pathologic Basis of Disease, 11th ed. (2026)

Chapter 21: Ureters—Tumors and Tumor-like Lesions

Related Chapter 21 sections: Urothelial Neoplasms; Obstructive Lesions

Related Chapter 20: Urothelial Carcinoma of the Renal Pelvis