Former President Joesph Biden has what a spokesman described as a “small nodule” in his prostate. How worried a patient should be by such a finding depends on the circumstances, urologists said.

In some cases, nodules are caused by inflammation, which can make the prostate feel firmer, or can lead to calcifications in the prostate that feel like nodules. These are benign.

They can also result from a common condition in older men, nodular benign prostatic hypertrophy, in which nonthreatening nodules form in the prostate, enlarging it. These also pose no risk.

But in the worst cases, they can be cancers.

When a urologist feels a nodule in a man’s prostate, it is not always clear what to make of it, said Dr. Scott Eggener, a urologist at the University of Chicago.

“There absolutely are times when it is vague and equivocal and you don’t know what it is,” he said, adding that a growth may feel like “a big bulky rock that is almost certainly cancer.”

But, Dr. Eggener said, he wonders why a doctor was manually examining Mr. Biden’s prostate in the first place. Perhaps he had a new symptom, like a urinary issue, or pain, or an elevated level of prostate-specific antigen, or PSA, a blood protein whose level rises with prostate cancer.