A 24 year old sexually active male
complains of painless warts on his penis.
He is worried that he may have
transmitted them to his girlfriend.
Biopsy of the lesions shows cells with perinuclear
cytoplasmic vacuolization and nuclear enlargement.
The doctor treats the patient by chemically
ablating the warts with 1% acetic acid solution.
The patient encourages his
girlfriend to get tested too
and he is worried that she may get an increased risk of
developing malignancy if she has contracted the condition.
What cancer is this
patient worried about?
Answer choice (A)
- kaposi sarcoma
Answer choice (B) -
Answer choice (C) -
hairy cell leukemia
Answer choice (D) -
and answer choice (E) -
Now take a moment to come to the answer
alone before we go through it together.
Now let's go through
the question together.
Now this is a microbiology question.
For even though we're showing
a pathological lesion,
we need to know how the underlying
pathophysiology and the microbiology works
to identify the organism at play and what
cancer risk that organism induces.
Now this is a 2-step question.
The first step is to diagnose
the cause of the warts
and then we have to determine what type
of cancer is associated with these warts.
And of course the stem is required as it provides
significant clinical information and image
and the type of question that we need to pursue.
So let's walk through
this question together.
Step 1- we need to determine the
diagnosis and the cause of the warts.
Now this patient has what is called genital warts
which is also named 'condylomata accuminata'.
Now genital warts are caused by
human papillomavirus or HPV.
Now human papillomavirus is the most
common sexually transmitted infection.
Now that we know the patient has
genital warts and is caused by HPV,
we have step 2 of this question which is determining
what type of cancer is associated with HPV infections.
Now the serotypes 6 and 11 of HPV are related
to approximately 90% of genital warts.
Now, HPV infection increases the risk of cervical cancer
and cancers of the vulva, vagina, penis and anus.
Now let's refer to our image where we can see how
cervical cancer can be related and caused by HPV.
We'll start with the image of the cervix
shown there and also shown the uterus
and those green little dots we have the
infection caused by human papillomavirus.
And then we zoomed in to actually look at the basal
cell in the cell layers within the actual cervix itself
and we see that we have
infection of the basal cells.
And then weeks later, we have HPV in the epithelial cells
actually inside and we even have viral replication.
Now thankfully, 90% of people will self
heal without intervention within 2 years.
Now looking several decades into the
future, what we can have happened is
about 0.8 percent of people exposed to human
papillomavirus will have developed cancer
and it will be invasive as we can see as it goes through the
basal cell layer and can develop cervical cancer as in this case.
So the answer to this question then is
answer choice (E) - cervical carcinoma.
Now let's go through some
of the other answer choices
to discuss what are the microbiology associated
wth the other type of cancers that we see listed.
Now answer choice (A) shows kaposi sarcoma which
is associated with human herpes virus 8.
Answer choice (B) which is Burkitt lymphoma
is associated with Epstein-Barr virus
Answer choice (C) hairy cell leukemia is
associated with human T-lymphotropic virus type 1.
And answer choice (D) which is hepatocellular carcinoma
is associated with hepatitis B and C viruses.
Each of these is extremely high-yield to know
essentially fundamental basic microbiology knowledge
that we should have available on
our memory at a drop of a hat
for either examination of USMLE step 1
or upon questioning during the wards.
So in this case, the answer is
again (E) - cervical carcinoma.
Now let's go over some high-yield facts
regarding genital warts and HPV.
Now genital warts, which is also called condyloma accuminata
is when you will see on a patient as we do on the image,
small bumps or groups of bumps in the genital area and
this can be associated with pain, discomfort or itching.
As we see in the image, this is the ventral
aspect of the penis and we have these lesions
right at the junction of the glans and the- shaft of the penis and
several small lesions in the ventral aspect of the shaft itself.
Now these lesions can be small or large,
they can be flat or they can be raised.
But most commonly they do
look like cauliflower,
very important for your board exams to keep
this image in mind in case you see it again.
And very important to note that genital
warts can affect both men and women.
Now almost all cases of genital warts are caused
by human papillomavirus serotype 6 and 11.
Now speaking of human papillomavirus, HPV is the most common
sexually transmitted infection with 79 million Americans,
most in their late teens and
early 20s infected with HPV.
It is transmitted through intimate skin-to-skin
contact, generally through vaginal or anal sex
and can be transmitted by a person even if they are
asymptomatic and thus they are still cariers of the virus.
Now HPV infects the basal layer of the skin
and mucus membranes with viral replication
occuring following the latent period leading
the hyperkeratosis and wart formation,
very high-yield to know that basal
layer of skin and mucus membranes.
Now very very important to know - there are
more than 70 serotypes of human papillomavirus,
the HPV serotypes 6 and 11 are related to approximately
90 cases of condyloma accuminata or genital warts.
Now, these two subtypes 6 and 11
have a very low neoplastic potential
as we saw in our image that there's a
0.8 percent risk of developing cancer.
Now the other two serotypes that you need to know
which are high-yield that actually have a much higher
pre-neoplastic potential are serotypes 16
and 18 that are also seen in papillomavirus.