Testicular seminoma is a malignant germ cell tumor of the testes that is rarely encountered in clinical practice. Painless unilateral testicular swelling is most frequently reported by patients, but because of the indolent clinical course, the diagnosis may often be delayed. A thorough imaging, laboratory, and histological workup is mandatory in determining tumor stage.
Despite the fact that testicular tumors comprise about 1% of all malignancies seen in males, it is the most common solid tumor encountered in males between 15-35 years of age . Cryptorchidism is the most important risk factor for the development of testicular cancers , whereas genetic factors, a positive family history, and unexplained infertility have been associated with an increased incidence of this tumor  . The clinical presentation in virtually all patients starts with the appearance of a painless lump or swelling within the testes that is incidentally discovered by the patient himself  . Swelling is usually unilateral, and only a small number of males report bilateral symptoms . The presence of pain is noted in approximately a third of patients, most commonly in the form of a dull ache, whereas acute pain is seen in only 10% of cases . Fortunately, the majority of individuals are diagnosed in early stages of the disease, but abdominal or back pain, headaches, hemoptysis and other signs of distant tumor spread are seen in 25-35% of cases .
An extensive diagnostic workup is necessary if signs and symptoms are suggestive of a testicular tumor. A thorough patient history that will confirm the onset of swelling and accompanying symptoms (if present) should be performed, followed by a detailed physical examination of the scrotum. Testicular ultrasonography must be conducted immediately if swelling or a lump is observed, which may be sufficient to make an initial diagnosis . In order to classify the tumor into its appropriate stage, the following criteria should be used    :
Such criteria can only be obtained after a detailed imaging and histopathological workup, indicating that computed tomography (CT) and magnetic resonance imaging (MRI) of the pelvis, abdomen, and thorax, as well as microscopic examination of the tumor (most frequently performed after a sample is obtained during radical orchiectomy), are essential in order to make a definite diagnosis . For patients in whom metastatic spread is suspected, positron emission tomography (PET) scanning can be useful as well .