Renal Tumors

On this page

Renal Tumor Overview - Kidney's Lumpy Bumps

Kidney tumor types illustration

  • Renal tumors: diverse group, classified as benign or malignant.
  • Often detected incidentally; classic triad (hematuria, flank pain, mass) is uncommon, seen in <10% of Renal Cell Carcinoma (RCC) cases.
  • Major risk factors: smoking, obesity, hypertension, analgesic nephropathy, and genetic predisposition (e.g., Von Hippel-Lindau disease).
  • Malignant tumors (mainly RCC) are more common than benign (e.g., angiomyolipoma, oncocytoma).

⭐ Clear cell carcinoma is the most frequent subtype of RCC, constituting approximately 75-80% of cases, often associated with VHL gene mutations on chromosome 3p.

Benign Buddies - Harmless Kidney Knots

  • Angiomyolipoma (AML)
    • Components: Blood vessels, smooth muscle, mature adipose tissue.
    • Marker: HMB-45 positive.
    • Strongly associated with Tuberous Sclerosis (TSC).
    • Risk: Spontaneous hemorrhage if >4 cm.

    ⭐ AMLs in Tuberous Sclerosis are often bilateral & multiple; risk of life-threatening retroperitoneal hemorrhage (Wunderlich syndrome) if >4 cm.

  • Renal Oncocytoma
    • Origin: Intercalated cells of collecting ducts.
    • Gross: Classic mahogany brown color; may show central stellate scar.
    • Micro: Large eosinophilic cells with abundant granular cytoplasm (numerous mitochondria).
    • Generally benign course. Renal Angiomyolipoma Gross and Microscopic Pathology

RCC Spotlight - The Kidney Culprit

  • Risk Factors: Smoking (most significant), obesity, hypertension, cadmium exposure, acquired cystic disease (dialysis), genetic (von Hippel-Lindau).
  • Clinical Features:
    • Classic Triad (6-10%): Hematuria, flank pain, palpable abdominal mass. 📌 (Mnemonic: Heavy Flank Pain)
    • Paraneoplastic Syndromes: Polycythemia (↑EPO), hypercalcemia (PTHrP), hypertension (renin), Cushing's (ACTH), Stauffer syndrome (hepatic dysfunction).
  • Morphology:
    • Typically arises from renal tubules.
    • Gross: Yellow, variegated, often with hemorrhage/necrosis.
    • Micro: Clear cell (most common), papillary, chromophobe.
  • Grading: Fuhrman grading (nuclear features) or WHO/ISUP grading.

Renal Cell Carcinoma, gross cut section

⭐ Clear cell RCC is strongly associated with VHL gene mutations on chromosome 3p.

RCC Subtypes - The Varied Villains

  • Clear Cell RCC (ccRCC) (70-80%)
    • Genetics: VHL (3p del) (📌 VHL = Very Clear)
    • Histo: Clear cells (glycogen/lipid), chicken-wire vessels.
    • Prognosis: Variable, often aggressive.
  • Papillary RCC (pRCC) (10-15%)
    • Genetics: Type 1: MET, Trisomy 7, 17. Type 2: FH.
    • Histo: Papillary. T1: basophilic cells. T2: eosinophilic cells, prominent nucleoli.
    • Prognosis: T1 better than T2.
  • Chromophobe RCC (chRCC) (5-10%)
    • Genetics: Multiple chromosomal losses (📌 Chromo-phobes LOSE chromosomes).
    • Histo: Pale eosinophilic cells, plant-like membranes, perinuclear halo (Hale's colloidal iron +).
    • Prognosis: Good.

⭐ Clear Cell RCC is the most common subtype, strongly linked to VHL gene inactivation on chromosome 3p.

Wilms & Others - Childhood & Pelvic Foes

  • Wilms Tumor (Nephroblastoma): Most common renal malignancy in children (peak 2-5 yrs).
    • Genetics: WT1 (WAGR syndrome), WT2 (Beckwith-Wiedemann), CTNNB1.
    • Histology: Classically triphasic (blastemal, stromal, epithelial). Anaplasia indicates poor prognosis.
    • Presentation: Palpable abdominal mass, hematuria, hypertension. Wilms tumor triphasic histology
  • Urothelial Carcinoma (Renal Pelvis): Affects older adults.
    • Risk factors: Smoking, aniline dyes, cyclophosphamide, phenacetin.
    • Often multifocal (field effect); presents with painless hematuria.
  • Other Childhood Tumors:
    • Clear Cell Sarcoma of Kidney: Bone metastases common.
    • Malignant Rhabdoid Tumor: Aggressive; SMARCB1/INI1 gene mutation.

⭐ Wilms tumor is associated with WAGR syndrome: Wilms tumor, Aniridia, Genitourinary anomalies, mental Retardation (due to WT1 deletion).

High‑Yield Points - ⚡ Biggest Takeaways

  • Renal Cell Carcinoma (RCC): Most common adult renal tumor; clear cell type linked to VHL gene.
  • Classic RCC triad: hematuria, flank pain, mass; often presents late.
  • Paraneoplastic syndromes (e.g., polycythemia, hypercalcemia) are frequent with RCC.
  • Wilms' tumor: Most common renal malignancy in children; linked to WT1/WT2 genes, WAGR syndrome.
  • Angiomyolipoma: Benign; associated with tuberous sclerosis; contains vessels, muscle, fat.
  • Oncocytoma: Benign; large eosinophilic cells (mitochondria); may show central scar.
  • Transitional Cell Carcinoma (TCC) of renal pelvis: Smoking is a key risk factor.

Practice Questions: Renal Tumors

Test your understanding with these related questions

Which of the following statements about hypernephroma is true?

1 of 5

Flashcards: Renal Tumors

1/10

_____ Renal cell carcinoma has the best prognosis

TAP TO REVEAL ANSWER

_____ Renal cell carcinoma has the best prognosis

Chromophobe

browseSpaceflip

Enjoying this lesson?

Get full access to all lessons, practice questions, and more.

Start Your Free Trial