Pelvic schwannomas are rare; it is even more rare for a pelvic schwannoma to occur concurrently with a colon cancer. The authors report the case of a 62-year-old woman with a cecal mass that was surgically removed and the histopathologic diagnosis was adenocarcinoma of the colon. Meanwhile, aretroperitonealpelvic nodalmasswas detected as questionable metastasis of the primary tumor. A subsequent computed tomography-guided fine-needle biopsy was carried out to establish the tumor stage. Surprisingly, the fine-needle biopsy revealed a benign schwannoma. This unusual case posed a dilemma in postoperative staging of the colon cancer.