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USMLE Step 1 Forum USMLE Step 1 Discussion Forum: Let's talk about anything related to USMLE Step 1 exam |
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#1
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Hi, I'm new to these forums so sorry if this isn't where I should be posting questions. I'm listening to Pathoma videos right now and going through the text and I'm a bit confused about a couple things if anyone can help.
1. He says you shouldn't biopsy testicular tumors, which makes sense to me. However in this section it says that both embryonal carcinoma and choriocarcinoma can spread quickly and early through the blood, causing diffuse metastasis in the body, and both may have B-HCG elevated (choriocarcinoma will have it, and embryonal could have HCG and/or AFP elevated, or neither). Maybe I'm thinking too much into it but how can you differentiate between the two in a case where you have a tumor thats metastasized everywhere and an elevated B-HCG? Do you assume it's choriocarcinoma? Would this ever be asked of us, or do you just proceed with radial orchidoplexy without determining for sure the type of tumor, and then check the tumor histology after removing it? 2. In the ovarian tumor section, Leydig cell tumors produce androgen which cause virilization / hirustism in adults. In the testicular tumors section he mentions the same mechanism but says they cause gynaecomastia. This is an opposite, estrogen like effect- is this because the androgens are converted into estrogen by aromatase? If so, then why is that not happening in the female sertoli-leydig cell tumor? The same histological characteristic of Reinke crystals is seen in both so I'm curious about the different effects. Thanks!! |
#2
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Anyone??
I also have another question. How are hyperpigmentation and hyperkalemia used to distinguish primary from secondary adrenal insufficiency? |
#3
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In secondary adrenal insufficiency,there's inc ACTH.
ACTH has a byproduct called Melanin stimulating hormone,this MSH increases melanin production. Hope that helped. |
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#4
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I'm sorry I've no idea about those testicular and ovarian tumors; for your second question have a look at: https://en.wikipedia.org/wiki/Proopiomelanocortin
ACTH stems from a big complex called Proopiomelanocortin, which is cutted to the mentioned peptides. Hope that concept was kind of helpful Tim |
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