A 50-year-old white male presented with concurrent Paget's disease of bone and metastatic adenocarcinoma. Our review of the literature and our clinical experience suggests that carcinoma coexisting at the site of bone involved with Paget's disease occurs more commonly than has been recognized. The paucity of reports of tumor metastatic to sites of Paget's disease of bone may be due to an artifact of data collection. The differentiation of metastatic from de novo tumors must be accomplished by biopsy, and the diagnosis is essential for appropriate treatment. Commonly a correlation of known tumor types with Paget's disease is made, and metastatic tumors are excluded.