A 28-year-old male presents to the clinic with a 2-week history of a painless swelling in his right testicle. He first noticed the lump while showering, and although it has gradually increased in size, he reports no pain or discomfort. He denies any history of trauma, fever, or changes in urinary habits. The patient is otherwise healthy and has no significant medical history. He is sexually active with no history of sexually transmitted infections. He does not smoke, drink alcohol, or use recreational drugs.

On physical examination, the patient appears well-nourished and healthy. Inspection of the genital area reveals no obvious abnormalities, but palpation of the right scrotum reveals a firm, non-tender mass about 3 cm in size in the testicle. The mass is not transilluminating, and no signs of inguinal lymphadenopathy are noted. The left testicle appears normal with no palpable abnormalities. There is no evidence of hydrocele or varicocele.

Given the suspicion of testicular cancer, the patient is referred for an ultrasound of the scrotum. The ultrasound confirms the presence of a solid, heterogeneous mass in the right testicle, highly suggestive of malignancy. Further blood tests reveal elevated levels of serum alpha-fetoprotein (AFP) and beta-hCG, markers commonly associated with testicular cancer. A referral to an oncologist is made for further staging and management, including possible orchiectomy (surgical removal of the affected testicle) and follow-up treatment such as chemotherapy.