Abstract
Small renal masses (SRMs), typically defined as tumors ≤4 cm, are generally considered indolent and often managed with active surveillance. However, metastasis can occur even in small tumors. We report a 76-year-old man with a 26-mm renal mass and a periduodenal lesion initially suspected as pancreatic invasion. EUS-FNA suggested metastatic renal cell carcinoma. Nephrectomy revealed a 17-mm papillary RCC with high nucleolar grade (WHO/ISUP grade 2), tumor necrosis, venous invasion, and lymph node metastasis. This case underscores that biological aggressiveness may outweigh tumor size and that atypical imaging findings warrant careful evaluation.