Combined diagnostic imaging of a non-traumatic swelling of the popliteal cavity.

: A case of a 13-year-old female patient with a non-traumatic hard-elastic swelling in the right popliteal cavity, associated with functional impairment in maximal knee flexion and mild pain, is presented. The combination of clinical and radiologic findings (radiography, CT and MRI) suggested a number of differential diagnoses within bone and soft tissue tumors. The collected diagnostic information did not allow a definitive diagnosis that was established only after biopsy.