Final answer:
The symptoms described are suggestive of epididymitis, an inflammation of the epididymis which can cause scrotal pain, swelling, and may lead to more serious complications if untreated. Testicular cancer may present similarly but typically includes a lump and heaviness in the scrotum. Consulting a healthcare provider for an accurate diagnosis and treatment is essential.
Step-by-step explanation:
The condition that presents with a dull aching and fullness of the scrotum, swelling of the scrotum, negative transillumination test, and increased swelling with Valsalva maneuver is likely epididymitis. This is an inflammation of the epididymis, a tube located at the back of the testicles that stores and carries sperm. When this occurs, the scrotum may show symptoms such as pain, swelling, redness, and warmth. If the symptoms are acute and there is a presence of fever, it is likely acute epididymitis, which can be caused by a bacterial infection and is common in sexually active individuals. A serious consequence of untreated acute epididymitis can be an abscess or even infertility.
Testicular cancer may also cause similar symptoms, but typically presents with a lump or swelling in one of the testes and can include a feeling of heaviness in the scrotum. Testicular cancer most often affects young males between 20 and 39 years and is relatively more common in males of European than African ancestry.
It is important to consult a healthcare provider for an accurate diagnosis and appropriate treatment, as symptoms do not always indicate the underlying cause. An examination, possibly including an ultrasound, is a key step in diagnosing conditions affecting the scrotum.