A Subepithelial Lesion in the Colon Masquerading as Metastatic Prostate Cancer

Although the colon is a known site for tumor metastasis, it is relatively uncommon. In particular, prostate cancer may spread to the colon via locoregional penetration in locally advanced tumors. This can be easily seen on flexible sigmoidoscopy as an infiltrative lesion. However, a tumor deposit from prostate cancer presenting as a subepithelial lesion within the colon has never previously been reported. Here, we present a case of a patient with known prostate cancer who was found to have sigmoid colon uptake off imaging that demonstrated metastatic prostate cancer after endoscopic ultrasound-guided fine-needle biopsy of the subepithelial lesion.