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Hi, I'm James Smirniotopoulos and this is
a MedPix video for case 14328
This is also a case of the week and you can earn AMA category 1 CME credit from our website: rad.usuhs.edu/medpix
We have no significant financial nor other
conflict of interest disclosures. This case was contributed by Stephen J
Goldstein from the University of Kentucky
We have a 44-year-old woman was symptoms of sinusitis
who was evaluated by CT in Jan this
axial CT with bone windows demonstrates mucosal thickening
and some fluid accumulation within the sphenoid sinus.
We can also see that this sinus does not have air and
is completely opacified and very homogeneous
suggesting it is filled with fluid. The sinus also has slightly convex margins.
The sphenoid sinus is the third to aerate (pneumotize), and
the frontal is usually last and is not always aerated and often small.
In about eighty percent of cases, the sphenoid sinus will havel have a bone septation
and in 20 percent will have two septations. The sphenoid sinuses open or darin into
the posterior nasal cavity,
just above the call Wayne a in this pheno mortal recess
usually medial to the superior nasal turbinate.
Common lesions of the sphenoid sinus include sinusitis
as well as extension a pituitary adenoma,
inverting papilloma, metastatic disease & Lymphoma.
In this case, the lesion is so very homogeneous sugesting a fluid-filled
sinus cavity. Is this a "mucous retention cyst"?
Or, is it a mucocele? This is a very common and often
confusing question. A mucous retention cyst
is obstruction of a single paranasal sinus with retained secretions.
The prevalence is a little bit less than 10 - as found on panoramic dental films in otherwise normal patients.
But, up to 50% on CT scans done for orbit or
sinus symptoms show a mucocle.
Most mucous retention cysts are usually without symptoms and spontaneously regress.
They are typically lined by respiratory epithelium which may become modified
Retention cysts are most common in the maxillary sinus
and least commonly in the sphenoid signs. As an example, we show a CT image of
an asymptomatic maxillary sinus mucous retention cyst. We can see that the
lesion is relatively homogeneous and water like in its attenuation.
We can see that the sinus cavity is not remodeled by the cyst
and retains its normal shape as shown on the coronal image.
Using bone window display, we can see the classic
dome-shaped appearance of the upper margin of
the mucous retention cyst and, again, there is no
bony remodeling. Mucus retention cysts are most common in the maxillary antrum
and they are very prevalent and they have been observed to appear
and resolve without therapy. When they do become symptomatic the options should
include watchful waiting as well as treatment for the underlying sinusitis.
So our patient actually has a mucocele.l A mucocele is also fluid filled, and lined by
respiratory epithelium.
The fill with mucous secretions from the lining. The sinus drainage openind or "ostium"
is obstructed and the sinus cavity cannot drain, accumulating fluid.
This results in secondary expansion
of the sinus cavity with expansile bony remodeling. Histology is often nonspecific because of
the chronic nature of the obstructed sinus opening.
the most common location for an obstructed sinus and mucocele is in the frontal sinus;
and, the least common location is in the sphenoid sinus.
The sphenoid represents less than 10 percent of all mucoceles.
Now our patient returned for a follow-up visit in August because of worsening
symptoms
We can now see that there has been a progressive change with enlargement of
the sphenoid sinus cavity.
Further, there is high attenuation material accumulated within the sinus
cavity.
and we are not able to clearly see the bony margin of the sinus wall along the left lateral
maring - adjacent to the left middle cranial fossa in the area of the cavernous sinus
on this agile image we can see the mass homogeneous fluid signal
we can see the inferior, the middle,
and the superior nasal turbinates. Just as a reminder,
this is the location for the sphenoid sinus ostium
just medial to the superior nasal turbinate.
Our patient has now a new neurologic problem - an afferent pupillary defect in her
left eye. If we carefully compare the original image from January, back then
we could see the lateral bone margin. However, if we look at the current study
image from August, maybe the mass i snow expanded
and we have lost the bony detail from the lateral margin on the left side of the sinus
if we look more carefully at the MR scan, which we have already seen,
we can see the masshas fluid signal and we can also see the internal corroded flow
void in the cavernous sinus has a
a normal appearance on the right side but we do not see a corresponding
flow void on the left side and we have lost
the sclerotic bone margin. Now the differential diagnosis would include, in
addition an ossifying fibroma, inverting papilloma,
square a Miss carcinoma in base a bit to a teary-eyed no mccord Alma
in metastatic disease for a lesion involving the sphenoid bone
however in our case the case is homogeneous
and it was surgically treated with drainage up mucus eel
so again this has been a case about sphenoid sinus mucus seal
complicated by enlargement and erosion and scold a sin
invasion involving the cavernous sinus
Thank you very much for your attention I'm Jim Smirniotopoulos and I
approve this message.