Diagnostic tests in a person with known cancer with priapism
If a patient with known cancer presents with priapism, what diagnosis must be considered?
Metastatic disease to the penis is extremely rare but may result in a persistent nonsexual erection lasting >4 hours, known as malignant priapism, which is the initial clinical presentation in 20% to 50% of cases.
This occurs most commonly with prostate and bladder cancers and less commonly with colorectal cancer and other cancers.
Unfortunately, patients with metastatic disease to the penis generally have a very poor clinical outcome.
On cross-sectional imaging, enhancing penile nodules or diffuse infiltration of the corpora cavernosa by tumor may be seen.
Cavernosal thrombosis may also be present, which manifests as decreased or absent blood flow on Doppler US, increased T1-weighted and decreased T2-weighted signal intensity on MRI, partial or complete lack of enhancement of one or both corpora cavernosa, and expansion of one or both corpora cavernosa with mass effect upon adjacent structures.
