Pathology and Basic Science
Core concepts
Integrate histology, molecular biology, and pathophysiology. Know urothelial carcinoma variants and grading, prostate adenocarcinoma grading (Gleason/ISUP), renal cell carcinoma subtypes, and testicular germ cell tumors. Understand bladder carcinogenesis (field effect), tumor suppressor pathways (p53, RB), and prostate cancer biology (androgen receptor). Basic science includes renal physiology (countercurrent mechanism, acid-base), stone formation physics, and bladder smooth muscle pharmacology (muscarinic receptors, beta-3).
Traps
Do not confuse histologic grade with clinical stage. High-grade urothelial carcinoma has worse prognosis and needs aggressive intravesical therapy. Clear cell RCC has characteristic clear cytoplasm and rich vasculature; papillary RCC has papillary architecture. Gleason 4+3 is grade group 3, worse than 3+4 (group 2).
Worked example
A bladder tumor pathology report shows high-grade Ta: despite being non-muscle-invasive, high grade warrants BCG after TURBT. The trap is assuming Ta means low risk.
Exam strategy
Translate pathology into risk and management; memorize grade group conversions.