Stage I includes: pT1-4, N0, M0, SX. pT1: Tumor limited to the testis and epididymis without vascular/lymphatic invasion; tumor may invade into the tunica albuginea but not the tunica vaginalis. pT2: Tumor limited to the testis and epididymis with vascular/lymphatic invasion, or tumor extending through the tunica albuginea with involvement of the tunica vaginalis. pT3: Tumor invades the spermatic cord with or without vascular/lymphatic invasion. pT4: Tumor invades the scrotum with or without vascular/lymphatic invasion. N0: No regional lymph node metastasis. M0: No distant metastasis. SX: Marker studies not available or not performed. (AJCC 6th and 7th eds.) [from NCI]