🫘 Renal Masses & Cystic Diseases

🎯 Renal Cell Carcinoma

Complete RCC management from early stage to advanced disease

• Size-Based Risk: T1a (5.4%) → T2a (15-20%) metastatic rates
• Histologic Impact: Clear cell highest risk, chromophobe lowest
• Immunotherapy Revolution: Pembrolizumab + axitinib first-line
• Active Surveillance: Safe for selected T1a lesions
• Cryoablation Success: 95% success rate for ≤4cm tumors
• Long-term Outcomes: 10-year DSS 94% with cryoablation

🔴 Angiomyolipoma

Most common benign renal tumor - Conservative management

• Active Surveillance: First-line for most patients, including >4cm
• Conservative Success: 67% avoid intervention long-term
• Classification: Fat-rich, fat-poor, epithelioid variants
• Treatment Triggers: Pregnancy, growth >0.25cm/year
• TSC Association: mTOR inhibitors for multiple lesions
• Emergency Management: Retroperitoneal hemorrhage protocols

🩺 Renal Lymphoma & Metastases

Hematologic and metastatic disease to the kidney

• Renal Lymphoma: 5% CT detection, 30-60% autopsy studies
• Primary Origins: Lung, melanoma, breast, colon metastases
• B-cell NHL: Most common hematologic malignancy
• Diagnosis: Image-guided biopsy essential
• Treatment: Systemic therapy, not surgical
• Imaging Pattern: Bilateral enlargement, hypoenhancement

📊 Bosniak Classification 2019

Updated classification with enhanced precision

• Category I: Simple cysts - 0% malignancy risk
• Category II: Minimally complex - <1% risk
• Category IIF: Follow-up required - 0-38% risk
• Category III: Indeterminate - ~50% malignancy
• Category IV: Malignant-appearing - ~90% risk
• 2019 Updates: MRI integration, <30 HU benign rule

🧬 Autosomal Dominant PKD

Most common hereditary kidney disease worldwide

• Genetics: PKD1 (78%), PKD2 (15%) - progression correlation
• Risk Stratification: Mayo Classification 1A-1E
• Tolvaptan: First disease-modifying therapy approved
• Aneurysm Screening: 10-12% prevalence vs 2-3% general
• Liver Disease: 81.7% have hepatic cysts
• Height-Adjusted TKV: Best progression predictor

🔬 Other Cystic Diseases

Complete spectrum of cystic kidney diseases

• ARPKD: 1:20,000-50,000 births, PKHD1 mutations
• Nephronophthisis: AR inheritance, ESRD by age 13
• Medullary Cystic Disease: AD inheritance, hyperuricemia
• Medullary Sponge Kidney: 1:5,000 prevalence, stone risk
• Genetic Testing: Definitive diagnosis for complex cases
• Management: Symptomatic care, complication prevention

📅 Bosniak IIF Surveillance

• Initial Protocol: 6 months CT/MRI to establish stability
• Years 1-3: Annual imaging if stable
• Stable Rate: <1% malignancy in stable lesions
• Progression Criteria: New enhancement, thickness, nodules
• Patient Factors: Age, comorbidities, anxiety level
• Extended Follow-up: Consider longer intervals after 5 years

📈 ADPKD Monitoring

• High-Risk Patients: Annual height-adjusted TKV measurement
• Imaging Modality: MRI preferred (no radiation)
• Progression Assessment: TKV growth rate calculation
• Treatment Response: Monitor tolvaptan efficacy
• Aneurysm Screening: MRA every 5-10 years to age 60
• Liver Disease: Assess polycystic liver progression

🔍 Active Surveillance RCC

• T1a Protocol: CT/MRI at 3-6 months, then annually
• Growth Rate: Document size progression over time
• Intervention Triggers: Rapid growth, size >4cm, symptoms
• Patient Selection: Elderly, comorbid, patient preference
• Oncologic Safety: No adverse outcomes from delayed treatment
• Quality of Life: Preserve function, avoid treatment toxicity

🎯 Angiomyolipoma Follow-up

• Initial Assessment: CT/MRI at 6-12 months for growth rate
• Stable Lesions: Annual imaging for 2-3 years, then extend
• Growth Threshold: >0.25 cm/year suggests intervention
• Aneurysm Surveillance: Monitor for intralesional aneurysms
• TSC Patients: More frequent monitoring, consider mTOR inhibitors
• Pregnancy Planning: Pre-conception counseling and monitoring