This app is the free version in the Tumorpedia series, a collection of apps that serve as an encyclopedia of orthopaedic oncology based on www.bonetumor.org. This version includes a selected collection of 28 orthopaedic tumors. Each topic is divided into general information, incidence and demographics, xrays, MRI, CT, pathology, differential diagnosis, and treatment. The amount of information presented for each topic is variable, but generally a specific and informative overview of the topic is included. The images are especially useful for demonstrating “typical” appearances on imaging exams and pathologic specimens. The app also includes an “updated” feature, suggesting that the database may undergo regular updates in the future. Overall, this series of orthopaedic tumor information is a useful reference for orthopaedic trainees, nurses, and other medical providers who diagnose and treat musculoskeletal tumors.