Although the incidence of testicular cancer has increased over the past few decades, testicular tumours are still rare and many GPs will only see one or two new diagnoses in their career. When examining scrotal swellings, the key question is whether the lump is intra- or extra-testicular, as palpable intra-testicular lesions are highly likely (around 90%) to be malignant, whereas those lying outside the testis are usually benign.