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Urology/Lump on penile shaft during arousal


Age 32, male.  Taking mesalamine (500mg capsules, 2 capsules three times a day) and infleximab (remicade, one dose every 8 weeks.)  Both medications are for Crohn's disease.  Location: USA, Alabama.

A few weeks ago during masturbation I found a lump on the shaft of my penis, on the underside, around where the scrotum meets the shaft.  The lump is internal, feels hard, roundish, and is no more than a millimeter or two across, feeling overall something like a grain of sand.

I was unable to locate it later when not aroused, yet managed to find it again during masturbation.  Keeping my finger on it after arousal, the bump doesn't go away, but feels like it moves to the right, going deeper into the tissue between the corpus spongiosum and the corpus cavernosum on the right side until I can no longer feel it.  I have to pinch fairly deep into the penis to feel it while flaccid, and even then, not being totally familiar with the feel of my internal structures, it's hard to tell if I have actually located it.

The lump has persisted for a couple weeks, and is consistently present during arousal, taking 5 to 10 minutes to appear once the penis is erect.

There is no pain associated with the lump, and there have been no changes in erectile or urinary function, nor does the lump seem to be changing in size.  There have been no outwardly visible chnges in the genital area.  Also, I am circumcised in case that is relevant.

Other the the Crohn's, past history includes one melanoma in situ (located on arm, 2 years ago, follow up biopsy shows no reoccurrence) and exposure to HPV (4 years ago, not a genital wart strain, but specific strain is unknown to me, resulted in no outward changes to genital area).

I have an appointment with my doctor in a few weeks.  If I could get some idea of what to expect as far as what it might be, or suggestions as to what diagnostic tests I should request, I would greatly appreciate it.

Many thanks.

Matthew, as you might imagine, for this type of problem it is not possible for me to make an exact diagnosis or give recommendations over the internet because of the inability to take a more complete history and do a physical examination.  However, I shall try to help you.

What you are describing is most likely a type of benign inclusion cyst.  These typically originate in normal tissue planes and are, therefore, somewhat moveable and may be difficult to find when you look for them.  There are many lesions that can present as tiny (1-2mm) lesions in the penis.   The possibilities would include tiny areas of calcification or rarely amyloid deposits.  I am sure from your description that yours is not a case of Peyronie's disease.  In the latter, larger plaques of scar tissue form on the membrane surrounding the corpora cavernosa.  Although totally benign, they can, on occasion, produce mild discomfort and curvature of the penis with erection.

Even with proper examination by a urologist, a definitive diagnosis could probably not be made unless the lesion was excised and examined pathologically.  Most likely, surgery would not be recommended unless the lesion began to grow, which would be very unlikely from your description.  I suggest you see a urologist in consultation as you are much more likely to get a better evaluation for this type of problem than from your family doctor.  Good luck.  


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Arthur Goldstein, M.D.


Problems or questions related to the field of urology; ie urinary stone disease, urinary cancers (kidney, bladder, prostate, testis, etc.), urinary infections, etc. I no longer answer questions related to erection problems or male sexual dysfunction.


I am retired from the active practice of urology. My 34 years was totally in the clinical field and involved the entire gamut of genitourinary problems, with special interest in endourology.

American Medical Association, American Urological Association, American College of Surgeons

College degree - BS Medical degree - MD Master of Science - MS

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