Capsule endoscopy (CE) is a highly effective and safe technique for small-bowel evaluation, though capsule retention occurs in fewer than 2% of cases and may uncover significant pathology. We report a 56-year-old woman with iron-deficiency anemia and positive fecal occult blood whose CE revealed a friable, stenosing proximal jejunal lesion that blocked capsule progression. Retention was confirmed radiographically, and the capsule was successfully retrieved endoscopically. Biopsies identified a moderately differentiated jejunal adenocarcinoma, subsequently treated with curative surgery and adjuvant chemotherapy. This case illustrates how capsule retention, despite being rare, can represent the first diagnostic clue to small-bowel malignancy and highlights the need for pre-procedure assessment for potential strictures to ensure safe CE use.