Histo: Urology Flashcards
What are urinary calculi?
Crystal aggregates in the renal collecting ducts.
What is the epidemiology of urinary calculi?
- 15% lifetime incidence
- M:F = 3:1
List the three main types of urinary tract calculi in order of prevalence.
- Calcium oxalate (Weddelite) - 75%
- Magnesium ammonium phosphate (Struvite) - 15%
- Urate - 5%
What is the basic mechanism behind the formation of calcium oxalate stones?
Increased urinary calcium concentration (hypercalciuria)
List some underlying conditions that can lead to the formation of calcium oxalate stones.
- Absorptive hypercalciuria - excessive calcium absorption from the gut
- Renal hypercalciuria - impaired absorption of calcium in the proximal renal tubule
- Hypercalcaemia e.g. hyperparathyroidism (RARE)
Describe how magensium ammonium phosphate stones (triple stones) are formed.
- Results from infection by a urease-producing organism (e.g. Proteus)
- Ammonia produced by the bacteria alkalinises the urine leading to precipitation of magnesium ammonium phosphate stones
- They can become very large (e.g. staghorn calculi)
Which patients are predisposed to the formation of urate stones?
Conditions causing hyperuricaemia
- Gout
- Rapid cell turnover (e.g. chemotherapy)
Most patients do not actually have hyperuricaemia or increased uric acid excretion in urine
- Believed to be due to tendency to produce slightly acidic urine
What are 3 common presentations of urinary calculi?
- Haematuria
- Colic
- Recurrent UTI
Where do urinary calculi stones tend to get stuck within the urinary tract?
- Pelvic-ureteric junction
- Pelvic brim
- Vesico-ureteric junction
This causes renal colic symptoms
What are the consequences of large stones?
- Obstruction
- Risk of infection
- CKD
This is because large stones tend to get stuck in the kidney
List three types of benign renal neoplasm.
- Papillary adenoma
- Renal oncocytoma
- Angiomyolipoma
Define papillary adenoma.
Benign epithelial kidney tumour with a papillary or tubular architecture
- They must be <15 mm in size
- Well-circumscribed
- Linked to papillary renal cell carcinoma
Frequent found incidentally in nephretomies and autopsies (especially in those with damaged kidneys e.g. CKD)
What are the genetic associations of papillary adenomas?
- Trisomy 7 and 17
- Loss of Y chromosome (can occur in the cells of men with age)
What is a renal oncocytoma?
- Benign epithelial kidney tumour composed of oncocytic cells
- They are usually well-circumscribed and usually sporadic
NOTE: often an incidental finding
Oncocytes are cells that have accumlated numerous mitochondria
Name a syndrome that is associated with renal oncocytoma.
Birt-Hogg-Dubé syndrome
Describe the histological appearance of oncocytes.
- Large cells
- Pink (eosinophilic) granular cytoplasm (due to numerous mitchondria)
- Prominent nucleolus
What is an angiomyolipoma?
Benign mesenchymal kidney tumour composed of thick-walled blood vessels, smooth muscle and fat
- Derived from perivascular epitheloid cells
- Mostly sporadic
NOTE: often an incidental finding but may cause flank pain, haemorrhage and shock (if >4cm)
Which hereditary condition is associated with angiomyolipoma?
Tuberous sclerosis
What is renal cell carcinoma?
Malignant epithelial kidney tumour
List some risk factors for renal cell carcinoma.
- Smoking
- Hypertension
- Obesity
- CKD requiring long-term dialysis
- Genetic (e.g. von Hippel Lindau)
How does renal cell carcinoma tend to present?
- Painless haematuria (50% of cases)
- Remaining cases are detected incidentally on imaging
Name the subtypes of renal cell carcinoma in order of prevalence.
- Clear cell renal cell carcinoma (70%)
- Papillary renal cell carcinoma (15%)
- Chromophobe renal cell carcinoma (5%)
What are clear cell renal cell carcinoma.
- Epithelial kidney tumour composed of nests of clear cells set in a delicate capillary vascular netwrok
- Grossly apears golden-yellow with haemorrhagic areas
What is a common cytogenetic finding in clear cell renal carcinoma?
Loss of chromosome 3p
What are papillary renal cell carcinoma?
Epithelial kidney tumour composed of papillae and/or tubules
- By definition >15mm in size
- Cytogenetics show trisomy 7 and 17, and loss of Y chromosome
- 2 histological subtypes
- They appear grossly as a fragile, friable brown tumour
NOTE: this is the malignant counter part of papillary adenoma.
Describe the histological appearance of the two types of papillary renal cell carcinoma.
- Type 1: composed of a single layer of small and flat cells. You see a lot of islands of cells.
- Type 2: there is pseudostratification of the cells
NOTE: type 2 tends to have a worse prognosis than type 1
Define chromophobe renal cell carcinoma.
Epithelial kidney tumour composed of sheets of large cells that display
- Soap-bubble appearance
- sharply-defined cell borders
- reticular cytoplasm
- thick-walled vascular network
NOTE: grossly appears as a well-circumscribed solid brown tumour
What is the 5-year survival for renal cell carcinoma?
60% across all types
What grading system is used for clear cell and papillary renal cell carcinoma? What staging system is used?
- Grading: ISUP Nuclear Grade (1-4)
- Staging: TMN 8th Edition
What risk progression index is used for clear cell carcinoma?
Leibovich Risk Model (takes into account grade, stage, lymph node status etc.)
What is Nephroblastoma (Wilm’s tumour)?
Malignant triphasic kidney tumour of childhood:
- Blastema (small round blue cells)
- Epithelial
- Stromal
Typically present with an abdominal mass in children aged 2-5 years
NOTE: 95% have an excellent prognosis
Second most common childhood malignancy
What is urothelial carcinoma?
Also known as transitional cell carcinoma
Group of malignant epithelial neoplasms arising from the urothelial tract
- Bladder
- Renal pelvis
- Ureters
What are the major risk factors for urothelial carcinoma?
Smoking
Aromatic amines
How do most urothelial carcinomas present?
Haematuria
What are the three main subtypes of urothelial carcinoma?
- Non-invasive papillary urothelial carcinoma
- Infiltrating urothelial carcinoma
- Flat urothelial carcinoma in situ
Describe the macroscopic appearance of non-invasive papillary urothelial carcinoma.
- Appears as frond-like growths
- Can be divided into low or high grade dependent on nuclear atypia
- Low grade tumours have low risk of progression to invasive disease
- High grade tumours have high risk of invasion - are genetically unstable and carry numerous mutations including RB and TP53
Describe the histological appearance of invasive urothelial carcinoma.
- This is urothelial tumour that has started showing invasive behaviour
- Once urothelial cells to invade, the morphology becomes very diverse (e.g. squamous, adenocarcinoma, sarcoma etc.)
- Treatment is based on the depth of invasion: lamina propria, muscularis propria
What is flat urothelial carcinoma in situ?
High grade lesion in situ (high risk of progression to invasive)
Gross appeance: may be invisble or appear as a reddish area
Define benign prostatic hyperplasia. Which area of the prostate does it affect?
- Benign enlargement of the prostate gland as a consequence of increased cell number
- Arrises from the transitional zone (surrounds urethra)
Describe the epidemiology of BPH?
Very common - symptomatic in 25% of men by age 80
Histologically present in 90% of men by age 80
What is a possible mechanism for the onset of BPH?
Increased oestrogen with ageing induces androgen receptors and stimulates hyperplasia
List some treatment options for BPH.
- Alpha blockers
- 5alpha-reductase inhibitors
- TURP
How can BPH present?
- LUTS (most common)
- UTI
- Acute urinary retention
- Renal failure
What symptoms are included in LUTS?
- Frequency
- Urgency
- Nocturia
- Terminal dribbling
- Hesitancy
- Incomplete voiding
- Poor flow
- Straining
What is the most common malignant tumour in men?
Prostate cancer (adenocarcinoma)
Descibe the epidemiology of prostate adenocarcinoma?
- 25% of all male cancers
- Will affect 1 in 8 men
- 5-10x increased risk if first degree relative is affected
What is the precancerous lesion that prostate cancer arises from?
Prostatic intraepithelial neoplasia (PIN)
List some mutations that are implicated in prostate cancer.
- PTEN
- AMACR
- P27
- GST-pi
What are presenting symptoms of prostate adenocarcinoma?
- Usually asymptomatic - diagnosed on biopsy following raised PSA or DRE
- May have LUTS
- May present with metastatic disease - back pain, pathological fracture
- Weightloss and loss of appetitie if extensive disease
What scoring system is used for prostate cancer? Explain how it is calculated.
Gleason score (1-10)
- Expressed as x + y = z
- Calculated by adding the top two most common patterns/grades seen on histological grading
- Higher scores are associated with poorer prognosis
What is the epidemiology of testicular germ cell tumours?
- Account for 90% of testicular tumours
- Arise in men aged 20-45
List some risk factors for testicular germ cell tumours.
- Undescended testicles
- Low birth weight
What is the pre-malignant lesion associated with testicular germ cell tumours?
Germ cell neoplasia in situ
NOTE: this process probably begins in foetal life
Which genetic factor is associated with testicular germ cell tumours?
Amplification of i12p
How to testicular germ cell tumours present
Painless lump
10% present with symptoms related to metastasis
- Back pain
- Cough
- Dyspnoea
List the five histological subtypes of testicular germ cell tumours.
- Seminoma (most common)
- Embryonal carcinoma
- Post-pubertal teratoma
- Yolk sac tumour
- Choriocarcinoma
Single tumour may be purely one subtype or contain a mixture of multiple subtypes
Describe the histological appearance of:
- Seminoma
- Embryonal carcinoma
- Post-pubertal teratoma
- Yolk sac tumour
- Choriocarcinoma
-
Seminoma
- Mostly made up of clear cells with a prominent lymphocytic infiltrate
-
Embryonal carcinoma
- High-grade appearance with prominent nucleoli
-
Post-pubertal teratoma
- The tumour is trying to produce a variety of tissues (e.g. keratin, cartilage, glands)
- This is malignant - any component of the tumour can become malignant
-
Yolk sac tumour
- Smaller cells
- Lace-like pattern
- Some pink inclusions
-
Choriocarcinoma
- Made up of two cell types: cytotrophoblasts (clear looking cells) and syncytiotrophoblasts (multinucleated cell)
- NOTE: both components are needed to define choriocarcinoma
How are testicular germ cell tumours treated?
They are highly sensitive to platinum-based chemotherapy
Excellent prognosis: 5-year survival is 98%
Name three types of testicular non-germ cell tumours.
- Lymphoma - more in older men; highly aggressive with poor prognosis
- Leydig cell tumour - may cause precocious puberty (if pre-pubertal)
- Sertoli cell tumour - 90% benign
What are the causes of epididymitis?
- <35 years = N. gonorrhoea and C. trachomatis
- 35+ years = E. coli
What is a variocele and what is a hydrocele?
Variocele - dilated veins of the pampiniform plexus
Hydrocele - fluid accumulation between layers of tunica vaginalis
What is an adenomatoid tumour?
Benign tumour consisting of small tubules lined by mesothelial cells
List some types of benign penile diseases.
- Lichen sclerosus - inflammatory condition that causes phimosis
- Zoon’s balanitis - inflammatory condition that causes red areas
- Condylomas (gential warts) - HPV6 and 11
- Peyronie’s disease - scarring, inflammation and thickening of the corpus cavernosa
Penile lichen sclerosus also know as balanitis xerotica obliterans
List some risk factors for penile carcinoma.
- HPV
- Smoking
- Chronic lichen sclerosus
List and describe some benign diseases of the urethra.
- Urethritis - gonorrhoea and chlamydia
- Prostatic urethral polyp - papillary lesion in the prostatic urethra
- Urethral caruncle - common lesion at the urethral meatus in women
NOTE: malignant diseases include urethral carcinoma (squamous cell carcinoma) and malignant melanoma
List and describe some diseases of the scrotum.
- Epidermoid cyst (common)
- Scrotal calcinosis
- Angiokeratomas (benign vascular lesions)
- Fournier’s gangrene - necrotising fasciitis of the scrotum and perineum
- Scrotal squamous cell carcinoma
