<--- This is a picture
of the bottom of the right foot of a patient
with two little seed corns that are also called porokeratotic lesions or plugged sweat ducts.
Note that the seed corns seem to occur in the middle of a more typical and
regular callus. They seem to be a specialized callus. Whatever they are called they are
They grow into a second little callus that feels like you are walking on a little grain of sand
or rice. When you pick at them you often get a little piece of skin from the center that
people sometime mistake for a "seed", hence the name. When the seed comes out
you are under the wonderful delusion that you have gotten the center of the lesion and you
are done with the thing. Wrong-O! the thing is still there and continues to grow and cause
complications.
1. 
2. 
The left picture is a photograph of
another patient with a little seed corn (porokeratotic lesion) on the bottom of
the right foot. The second picture (2) shows it in close-up. It is called a seed
corn because picking at it with a fingernail often results in the removal of a
little piece of keratin that tends to make people think in unfounded optimism
"I've gotten it our at last." Sorry, but you haven't. We will see you
in the office.
Why they even develop is still a mystery. The
best guess is they are a special type of callus. In fact they seem to develop in calluses.
In the case pictured it is developing in a linear callus running between the first and
second metatarsal heads of the foot. Look closely and you will see two separate seed corns
in the long callus.
They are called plugged sweat ducts because of
the mistaken notion that an underlying sweat duct must be plugged. Rumor has it that some
researcher found a sweat gland under a lesion when looking at it with a special electron
microscope (and you thought your job was boring). Later research has never verified this
finding and the name is probably an anomaly.
Treating
The Aggravating Little Monster (ALM)
Treatments for a porokeratotic lesion are as
follows:
1. Ignore it!
This is a benign lesion that can be safely ignored if it does not cause any harm
and doesn't hurt. It does not "need" treatment just because it is
there.
2. Wear comfortable
shoes and socks. If wearing padded shoes and socks keeps the ALM from hurting, then
go for it. Ask at the office for our list of shoe recommendations.
3. Trimming the
lesion. In the office I can make these guys stop hurting for weeks (sometimes
many weeks or months) by just trimming the lesion with a sharp scalpel blade.
4. Padding the lesion.
Putting a pad around the lesion will protect the ALM and frequently keep it from
hurting. Putting a pad on the lesion is a natural thought when something hurts but avoid
that; put the pad around the lesion. In the office I use an "aperture" pad made
of felt with a circle cut into it. Putting the pad around the lesion makes it feel
much better.
5. Removing it
surgically. Sometimes an attempt will be made to remove the ALM under local
anesthesia using a scalpel blade and a tool that I call a "melon baller for
ants" (technically a curette) that scoops the lesion out of the skin. While it works
great for warts, for a known sweat duct this is not a highly productive maneuver. It
permanently removes the ALM only 10-20% of the time. This is a great technique for a
"suspected" porokeratosis. With this technique you can remove foreign bodies
like glass or pet hair (really! - pet hair from short haired dogs and cats can actually
work its way into the skin). If this is really a wart masquerading as a seed corn, it will
also remove it.
6. Sclerosing: I
an one of the few people who use a technique to kill off seed corns with a series of injections.
I have lectured to this technique to other podiatrists a number of times. Just under the skin
I place 4% alcohol solution in anesthetic solution. This is more fully described under the
section called sclerosing. Click the green word sclerosing to go to the sclerosing page
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7. Surgical removal using
two completely through the skin incisions is 100%
effective but has a risk of permanent scarring. To reduce the scarring you should stay off
of your feet for 2-3 weeks (crutches!). Needless to say this is the least common method of
treating a seed corn. 7. Surgical removal using
two completely through the skin incisions is 100%
effective but has a risk of permanent scarring. To reduce the scarring you should stay off
of your feet for 2-3 weeks (crutches!). Needless to say this is the least common method of
treating a seed corn.
