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Renal Tumors

• There are three types of renal tumors: Nephroblastoma, renal cell carcinoma, and urothelial carcinoma of renal pelvis.

Wilm's Tumors

• Wilm's Tumors include: Malignant neoplasm of embryonic nephrogenic elements.
• It is the most frequent abdominal solid tumor in children, the most common primary renal tumor in children and the fourth most common pediatric malignancy.
• Wilm's Tumors occurs primarily in children around 50% of cases before 3 years and 90% before age 6.
• In 90% of cases a palpable abdominal mass is the initial sign.
• Hematuria, abdominal pain and hypertension may be present.
• In 90% of cases the tumor is sporadic and unilateral, where only 5% of cases the tumor arises in the context of three different congenital malformation syndromes: WAGR syndrome, Denys-Drash syndrome, and Beckwith-Wiedeman syndrome.
• Tumor development in some cases is associated with Wilm's tumor-associated genes WT1 and WT2, both located on the short arm of chromosome 11.
• Macroscopic analysis of the tumor presents Large, solitary, and well circumscribed renal mass in 90% of cases.
• The classic microscopic combination of embryonic blastemal, stromal and epithelial elements is observed in most cases.
• The treatment and clinical course of patients with Wilm's tumor depends on tumor stage and histologic category (presence or absence of anaplasia). -The long-term survival rate is 90%.
• Stage descriptions:
  • Stage I tumors are confined to the kidney and are completely resected.
  • Stage II tumors extend locally beyond the kidney but are completely resected.
  • Stage III tumors are residual, confined to the abdomen, without hematogenous spread.
  • Stage IV tumors have hematogenous metastasis or lymph node involvement beyond the renal drainage region.
  • Stage V tumors are bilateral.
• Anaplasia can be present which features enlarged hyperchromatic nuclei at least three times larger than normal nuclei and abnormal mitotic figures.
• Most Wilm's tumors are low-stage with favorable histology and have an excellent prognosis.
• Treatment for those patients includes nephrectomy, double-agent chemotherapy without radiotherapy.

Renal Cell Carcinoma

• Renal Cell Carcinoma is the most common primary cancer of the kidney.
• It arises from the renal tubular epithelium and occur most often in older individuals, with peak incidence in the sixth decade.
• The most important etiologic factor is tobacco smoking and most cases are sporadic where about 5% are inherited and are in the context of three distinct syndromes: Von-Hippel Lindau syndrome, Hereditary clear cell carcinoma, Hereditary papillary carcinoma.
• Common initial symptoms are hematuria (60%), flank pain (50%) or an abdominal mass (33%).
• Systemic metastasis is identified in 25% to 30% of patients at initial evaluation.
• The most common sites of distant metastases include the lung, bone, liver, adrenal gland, and brain.
• Tumors may produce a diversity of systemic symptoms and paraneoplastic effects attributable to ectopic hormone production: Polycythemia(erythropoietin), Hypertension(renin), Hypercalcemia(parathormone-related peptide), and Maculinization or Feminization(steroid hormones)
• RCC Clear Cell Type is the most common type of renal cell carcinoma which accounts for 70-80% of cases.
• In 98% of these tumors, there is loss of sequences on the short arm of chromosome 3, specifically 3p14, 3p21.3, and 3p25.3 (the location of the VHL gene).
• Most tumors appear centered on the cortex and are solitary and unilateral.
• Typical cross sections shows a yellowish spherical mass which contains hemorrhagic or cystic areas.
• Tumor cells have characteristic transparent cytoplasm in formalin-fixed sections.
• RCC Papillary Type accounts for 10-15% of renal cell carcinomas.
• It is not associated with 3p deletion.
• Multifocality and bilaterality are more common than in clear cell type.
• The most common type occurs in association to dialysis-related acquired cystic disease.
• Clinical Course includes staging and grading which both are very important
• RCC with Xp11.2 Translocation arises in children and young adults. A distinctive appearance occurs with alveolar and papillary architecture, clear cells, and psammoma bodies. It is characterized by the Xp11.2 translocation which can be detected by molecular testing. The gene product of the Xp11.2 locus is the TFE-3 protein and the Xp11.2 translocation may be shared with multiple partners, particularly with loci at chr. 1 and 17.
• Grading descriptions include:
  • Grade I: Round uniform nuclei, nucleoli not visible.
  • Grade 2: Irregular large nuclei, small nucleoli present.
  • Grade 3: Irregular larger nuclei, prominent nucleoli.
  • Grade 4: Pleomorphic nuclei, prominent nucleoli.
• Stage Descriptions include:
  • Stage I: Tumor confined within the renal capsule.
  • Stage II: Tumor confined by Gerota's fascia.
  • Stage III: Involvement of the renal vein, the vena cava or regional lymph nodes.
  • Stage IV: Invasion of adjacent organs or distant metastasis.
• Treatment involves a radical nephrectomy which is standard therapy for localized RCC.
• Immunotherapy protocols are under study.
• The average 5-year survival rate is about 45% but rises to 70% in the absence of distant metastasis.
• With the renal vein invasion or extension into the perinephric fat, the 5-year survival rate is reduced to 15% to 20%.

Urothelial Carcinoma of Renal Pelvis

• Urothelial Carcinoma accounts for about 5-10% of renal cancers in adults.
• Peak incidence occurs in the sixth to seventh decade of life.
• Epidemiologic risk factors for development of urinary bladder carcinoma are tobacco use, occupational exposure to arylamines, radiation, chronic inflammation, and calculi.
• Analgesic abuse is an important risk factor.
• Painless gross hematuria is the most common initial symptom (70% to 80% of patients).
• Depending on their location, large tumors may cause urinary outflow obstruction and hydronephrosis.
• Renal pelvis urothelial carcinomas are commonly associated with multifocal tumors.
• Synchronous or metachronous cancer are seen involving the ipsilateral or contralateral ureter, renal pelvis, or urinary bladder in about 40% to 50% of patients.
• Macroscopic analysis presents most commonly in exophytic papillary masses with frond-like growth on the mucosal surface.
• Tumors may extend down the ureter, or invade the renal medulla and cortex.
• Most tumors exhibit a papillary growth pattern, and they may be invasive or non-invasive microscopically.
• Grading takes into account cytologic features.
  • Grade I: Slight nuclear enlargement, without pleomorphism or mitotic activity.
  • Grade II: Moderate pleomorphism, prominent nucleoli, readily identified mitoses.
  • Grade III: Marked pleomorphism, prominent nucleoli and frequent mitoses.
• Treatment includes a nephoureterectomy with bladder cuff which is the standard therapy for pyeloureteral urothelial carcinoma. Adjuvant chemotherapy and radiation therapy may be used in the treatment of advanced disease.
• Approximately 75% of renal pelvis urothelial carcinomas are low-grade and low-stage. Muscle invasion and metastasis to regional lymph nodes are adverse prognosis factors.
• Patients with high-grade / high-stage lesions usually die within 2 years of diagnosis, where the overall 5-year survival rate after radical surgery ranges from 20% to 45%.
• The poorest prognosis factor is the presence of distant metastasis.
• Common sites include the lung, liver, bone and peritoneum.