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  #1  
Old 11-29-2009
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Zygote embryological origin

a 34 year old male patient is coming for a routine exam because he has a congenital disease. His BP is 130/70, pulse is 70 bpm, he weighs 80 Kg, BMI is 21. While you were examining his neck you found a 2x2 solitary mass just right to the middle of the base of the neck that he hasn't been aware of, it's not tender nor painful. There are no other masses, but you notice that his limbs are exceptionally long and he has a high arched palate. Which of the following share the embryological origin of his neck mass:

a- Parathyroid glands
b- Adenohypophysis
c- Spleen and kidneys
d- Odontoblasts
e- Retina
f- Gut luminal cells
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Old 11-29-2009
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I'd say this is thyroglossal cyst and it shares with parathyroids
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Old 11-29-2009
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Oh my God, this is so confusing
The high arched palate and the long limbs are pointing to Marfan syndrome.
But what has that got to do with the neck mass?
If it is a thyroglossal cyst then it must share the same origin with the thyroid and therefore endoderm and therefore choice F is the correct one.
But what if the mass is a branchial cyst because it's mentioned a little to the right!
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Old 11-29-2009
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I agree with cardalla
I think it's choice F
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Old 11-30-2009
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You are right, the patient has Marfanoid habitus, think of an association with a neck mass
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Old 12-02-2009
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This patient has marfanoid habitus, he has high arched palate, long limbs and tall stature (given the BMI and weight, this patient is 195 cm) If you see heavy weight and low BMI then this patient is really tall.

Marfanoid habitus is associated with MEN type 2b syndrome, along with skeletal abnormalities, abnormal dental enamel and multiple mucosal neuromas. MEN type2b is associated with medullary carcinoma which originates from parafollicular c cells, these originate from the neural crest.

Other common associations with marfanoid features : Marfan syndrom, Homocyctinuria (MR, atherosclerosis) and spontanuous pneumothorax.

a- and f- could not be the right answer as the parathyroid and enterocytes are both derived from endoderm.
b- adenohypophysis originates from surface ectoderm
c-spleen and kidney originate from mesodorm
d-odontoblasts originate from neural crest cells (correct answer) while enamel originates from surface ectoderm
e-Retina takes origin from neuroectoderm

Last edited by DrSeddik; 12-29-2009 at 03:09 AM.
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Old 12-02-2009
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Quote:
Originally Posted by DrSeddik View Post
This patient has marfanoid habitus, he has high arched palate, long limbs and tall stature (given the BMI and weight, this patient is 195 cm) I had a question in CK that implied tall stature in the same way, if you see heavy weight and low BMI then this patient is really tall.

Marfanoid habitus is associated with MEN type 2b syndrome, along with skeletal abnormalities, abnormal dental enamel and multiple mucosal neuromas. MEN type2b is associated with medullary carcinoma which originates from parafollicular c cells, these originate from the neural crest.

Other common associations with marfanoid features : Marfan syndrom, Homocyctinuria (MR, atherosclerosis) and spontanuous pneumothorax.

a- and f- could not be the right answer as the parathyroid and enterocytes are both derived from endoderm.
b- adenohypophysis originates from surface ectoderm
c-spleen and kidney originate from mesodorm
d-odontoblasts originate from neural crest cells (correct answer) while enamel originates from surface ectoderm
e-Retina takes origin from neuroectoderm
That's a great question
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