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NBME 21 Answers

nbme21/Block 2/Question#37
A 17-year-old boy is evaluated for ...
Craniopharyngioma🔍

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 +5  upvote downvote
submitted by sbryant6(91),

Craniopharyngioma with Calcifications and Cholesterol Crystals (motor-oil fluid). Remnant of Rathke's pouch. Not to be confused with pituitary adenoma.

dubywow  Also, craniopharyngioma is most common supratentorial childhood tumor. That was the big clue for me. +  



 +2  upvote downvote
submitted by aesalmon(65),

Can anyone explain why this is not a pituitary adenoma? Is it just a lack of other symptoms?

benzjonez  I think that they just wanted you to notice the **calcifications**. Per FA, "calcifications are common in craniopharyngiomas," whereas I don't think you'd expect to see calcifications in a prolactinoma. +10  
epr94  also the option is prolactinoma not broad pituitary calcifications and he doesnt show any specific signs of high prolactin +  
madojo  It says hes coming in for constituional delay in growth and puberty, i took this to mean that he had low LH, FSH due to decreased GnRH from the prolactinoma. Why did they have to say low-normal serum gonadotropin, why not just say normal? fck u nbme +  
madojo  It says hes coming in for constituional delay in growth and puberty, i took this to mean that he had low LH, FSH due to decreased GnRH from the prolactinoma. Why did they have to say low-normal serum gonadotropin, why not just say normal? fck u nbme +1  
ac3  @madojo I believe since suprasellar tumors can cause a mass effect on pituitary gland to decrease gonadotropin levels. Where as prolactinoma causes a rise in prolactin which downregulates gonadotropin secretion. Please correct me if I'm wrong +1  
teepot123  fa '19 pg 516 +  



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