## Why option 1 is right Renal cell carcinoma originates from the **proximal convoluted tubule epithelium**. The clear cell subtype accounts for 70–80% of all RCC cases and is characteristically associated with **VHL gene mutations on chromosome 3p25** (von Hippel-Lindau syndrome, both sporadic and hereditary forms). The heterogeneous solid mass marked **A** with internal vascularity and hypoechoic foci on ultrasound is the classic imaging presentation of RCC. This option directly expresses the pathogenesis and molecular basis of the most common RCC subtype, which is the anchor fact from the textbook. ## Why each distractor is wrong - **Option 2**: Collecting duct carcinoma is a rare and aggressive RCC subtype, but it does NOT arise from the collecting duct epithelium in the context of RCC classification—it is a distinct entity. More critically, it is NOT the most common subtype and is associated with poor prognosis, not the typical presentation. The anchor requires knowledge of the proximal tubule origin and clear cell subtype prevalence. - **Option 3**: Papillary RCC (10–15%) is NOT the most common subtype—clear cell RCC is. Papillary RCC arises from proximal tubule epithelium but is associated with MET proto-oncogene mutations, not VHL. This distractor confuses subtype frequency and molecular associations. - **Option 4**: RCC does NOT arise from the loop of Henle epithelium. Chromophobe RCC (5%) has the **best** prognosis among RCC subtypes, not the worst. This option contains two factual errors designed to trap students who confuse RCC origins and prognosis rankings. **High-Yield:** Clear cell RCC (70–80%, VHL 3p25) > Papillary RCC (10–15%, MET) > Chromophobe RCC (5%, best prognosis) — all arise from proximal tubule. [cite: Rumack Diagnostic Ultrasound 6e Ch 9; Campbell-Walsh Urology 12e Ch 97]
Sign up free to access AI-powered MCQ practice with detailed explanations and adaptive learning.