Renal Tumours - Benign and Malignant😍

Benign Renal Tumours

• 4 cm is the size of decision for Kidney tumors

Angiomyolipoma

• Features:
• Type of Hamartoma
• Benign,
• common in 5th-6th decade,
• origin from perivascular epitheloid cells (EPC).
• Neovascular tumor
• Only condition where fat is seen in kidney
• A/w Tuberous sclerosis complex (TSC).

• Clinical Features:
• Usually asymptomatic.

CECT (IOC)

• Fat → looks dirty black on CT.

• B/L angiomyolipomas
• A/w tuberous sclerosis.

Management:

• < 4cm & asymptomatic:
• Observation.

• ≥ 4cm & symptomatic:
• Partial nephrectomy or nephron-sparing surgery.

• Bleeding positive:
• Angioembolization → Partial nephrectomy.

Oncocytoma:

• Color: Mahogany brown.

• Most common benign kidney tumour.

• Etiology:
• Sporadic > Familial (common in Birt-Hogg-Dubé Syndrome).

• Clinical Features:
• Usually asymptomatic.

• Gross/Radiology: 
• Central stellate scar.

• Microscopy:
• Rich in mitochondria ("oncocyte" means mitochondria).
• Eosinophilic cytoplasm (rich in mitochondria),
• tan-brown appearance,
• cytokeratin negative (differentiates from chromophobe RCC).

• Mnemonic:
• Oncall (oncocytoma) is Mighty (mitochondria) Stella (stellate scar) Mahagony (Mahagony brown) → Oncall cannot sit (No cytokeratin)

• Investigations:
• CECT (IOC) shows central stellate scar.

• Management:
• < 4 cm: Observation.
• ≥ 4cm: Partial nephrectomy.

Birt-Hogg-Dubé Syndrome

• defect in Folliculin gene

• Plant like
• Oncocytomas
• Chromophobe RCC

• Fibrofolliculomas

• Trichodiscomas

• Lung cyst

• Multicoloured (chromophobe) Bird (Birt) Plant () site on Plant Fibre (Fibrofolliculoma) → playing disco (Trichodiscoma)

Malignant Renal Tumours

Wilms' Tumor (Nephroblastoma)

• Other name: 
• Nephroblastoma.

• Features:
• Most common paediatric renal malignancy.
• Second most common abdominal malignancy in children.
• Note: most common → Neuroblastoma

• Cell of origin: 
• Nephrogenic rest (undifferentiated mesenchyme of the kidney).

• Clinical Features:
• Age: 2 to 5 years.
• Mass:
• Does not cross midline (differentiates from neuroblastoma).
• Hematuria.
• ↑ Renin → Hypertension in children.

• Etiology:
• Sporadic > Familial.

• Investigations:
• CECT (helps differentiate from neuroblastoma).

Microscopy: 

• Triphasic tumor (E M B):
• Epithelial cells (form tubules).
• Mesenchymal cells (loose stroma).
• Blastemal cells (blue color, most prominent identifying feature).

Malformations:

• Horse shoe kidney → 4 times risk of Wilms' tumor.

• Cryptorchidism/undescended testis.

• Hypospadias.

Genetics:

• A/w WT1 gene and WT2 gene.

• National Wilms Tumor Staging (NTWS):
• Stage V: Bilateral Wilms tumor.

• Site of Metastasis
• Lung (most common) > Lymph node > Liver.

• Anaplasia:
• Indicates p-53 mutation.
• Leads to poor response to chemotherapy.
• Has prognostic significance.

WT 1 Gene

• Located on chromosome 11p13

• Most important gene for epithelial mesenchymal interaction in urogenital tract

• Mutation in WTI gene causes:
• WAGR syndrome
• Denys Drash syndrome

WAGR Syndrome

• Wilms tumor

• Aniridia: Absence of iris.

• Genitourinary abnormalities

• Mental retardation

Denys Drash Syndrome

• Denys–Drash = WT1 mutation → Congenital nephrotic syndrome (diffuse mesangial sclerosis) + Gonadal dysgenesis + Wilms tumor risk

• Male pseudo hermaphroditism

• Denys rash driving → loss kidney, and genitalia

• DD → gonadal Dysghenesis, Diffuse mesangial sclerosis

PRK-A Gene

• U/L renal agenesis

• PRK → Partial

RET/GDNF Pathway

• B/L Kidney agenesis

• GDNF → global reath (RET) → b/l

WT-2 gene (11p 15) mutation:

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Beckwith-Wiedemann syndrome.

• BWS = 11p15 imprinting defect → Overgrowth + Macroglossia + Omphalocele + Tumor risk (Wilms, Hepatoblastoma).

• Cause: ↑ copies of imprinted genes (placental overgrowth).

• LGA baby with hemihypertrophy.

• Macroglossia / Protruding tongue

• Omphalocele.

• Organomegaly (liver/spleen).

• Horseshoe kidney

• Double → Ear lobe creases.

• Increased risk of embryonal Tumors:
• Wilms tumor (nephroblastoma)
• Hepatoblastoma
• Neuroblastoma, rhabdomyosarcoma (less common)

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WT-2 gene (11p 15) mutation:

Beckwith-Wiedemann syndrome.

• BWS = 11p15 imprinting defect → Overgrowth + Macroglossia + Omphalocele + Tumor risk (Wilms, Hepatoblastoma).

• Cause: ↑ copies of imprinted genes (placental overgrowth).

• LGA baby with hemihypertrophy.

• Macroglossia / Protruding tongue

• Omphalocele.

• Organomegaly (liver/spleen).

• Horseshoe kidney

• Double → Ear lobe creases.

• Increased risk of embryonal Tumors:
• Wilms tumor (nephroblastoma)
• Hepatoblastoma
• Neuroblastoma, rhabdomyosarcoma (less common)

Staging (Children Oncology Group - COG)

Treatment

• Nephrectomy:
• Radical nephrectomy:
• For Stages 1-4.
• Stages 1/2: Chemotherapy:
• [Vincristine + Actinomycin D] for 18 weeks.
• Stage 3/4: Chemotherapy:
• [Vincristine + Actinomycin D + Doxorubicin] for 24 weeks AND.
• Radiotherapy.
• Partial nephrectomy:
• For Stage 5.
• Surgery + Chemotherapy + Radiotherapy.

Treatment of RCC vs. Wilms Tumor:

• RCC:
• Chemo/Radio resistant (Surgery is primary treatment).
• Prognostic factor: Pathological stage.

• Wilms Tumor:
• Chemo/Radio sensitive (Used along with surgery).
• Prognostic factor: Tumor histology.

Renal Cell Carcinoma or Hypernephroma

Adult - Renal Cell Carcinoma

General Information

• AKA:
• Hypernephroma,
• Renal adenocarcinoma,
• Grawitz tumor
• Grow → in RCC poor child

• Age at presentation: 60-70 yrs.

• Risk factors:
• Males > Females
• Smoking
• Obesity
• Petroleum products
• Asbestos
• DM, hypertension, tobacco, high protein intake,
• Thorotrast,
• Thorotrast linked to
• HCC,
• cholangiocarcinoma &
• renal cell carcinoma.
• Angiosarcoma (VAT → Plastic)

Clinical Features

• Classic Triad:
1. Abdominal mass
2. Hematuria
3. Flank pain

Paraneoplastic syndrome of RCC:

• Increased ESR (most common).

• Hypercalcemia

• Polycythemia

• Stauffer syndrome:
• increased serum bilirubin and ALP,
• IL-6 mediated
• RCC + nonmetastatic hepatic dysfunction.
• improves after surgery.

• Galactorrhea

• Cushing's syndrome, amyloidosis, anemia, vasculopathy, coagulopathy.

Hematogenous spread:

• Renal vein involvement → varicocele

Histologic Types

Clear Cell RCC

• Cells arranged in sheets.

• Nuclei are central.

• Peripheral clearing of cytoplasm due to glycogen/fat content.

• Clear sheet of paper

Papillary RCC

• Microscopy shows papillae (finger-like projections).

• Foamy histiocytes present within papillae.

• Psammoma bodies are seen.

• Most important determinant of malignant potential → the size of the tumor.
• Size < 1.5cm ⇒ Adenoma
• Size >=1.5cm ⇒ Papillary RCC

Psammoma Bodies

• Onion skinning, round pattern
• Mnemonic: PSM Squared

• Monckeberg's Sclerosis (CMD):
• Ca in tunica media (old age).

Feature	Details
Foci of dystrophic calcification	• Dead parasite, bacteria, TB • Degenerating tissue • Atherosclerosis Seen in • Papillary RCC • Papillary carcinoma of thyroid • Mesothelioma • Meningioma • Serous cystadenoma of ovary • Prolactinoma • Somatostatinoma Mesa (mesothelioma) ulla serious (serous) men (meningioma) like Milk (prolactinoma) & pappam (PP)

Stain for Calcium	Color	Mnemonic
Von Kossa stain	Black/kala color	Calcium sounds like calcine → Von Kossa kala
Alizarin Red S	Red color	Al for Alizarin

• First Site of Calcium Deposition:
• Mitochondria
• Exception (kidney): Basement membrane.

Chromophobe RCC

• Composed of polyhedral cells.

• Plant like cells

• Central stellate scar

• Cells have well-defined borders.

• Nuclei are central and resinoid.

• Prominent perinuclear clearing.

• Special stain: Hale's colloidal iron.

Investigations:

Staging of RCC (TNM Staging):

Management:

• Partial Nephrectomy:
• Indications:
• T1 tumors (< 7 cm),
• restricted to poles,
• bilateral RCC,
• RCC in solitary functioning kidney,
• Relative indications
• RCC in kidney with contralateral hydronephrosis/stones.

• Radical Nephrectomy:
• Structures removed:
• Kidney,
• para-aortic lymph nodes,  
• +/- ipsilateral adrenal gland,
• Gerota’s fascia,
• ureter till brim.

• Cryoablation:
• Tumor freezing (at -20°C) in
• T1a RCC (< 4cm).
• Elderly patients.
• Advanced/metastatic tumours

• Others
• Tyrosine kinase inhibitors (TKIs)
• Recommended for metastatic RCC
• Angioembolization
• Used in unfit patients