NBME 18 Metastatic carcinoma of the breast (NBME Answers)

Retired NBME 18 Answers

nbme18/Block 3/Question#21 (reveal difficulty score)
48 yo woman, gradual onset of back pain over ...
Metastatic carcinoma of the breast 🔍 / 📺 / 🌳 / 📖
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submitted by ∗ergogenic22(401)

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I went with metastatic breast because they made a point of saying metastatic as if the thyroid carcinoma has not spread to the bone.

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submitted by ∗flapjacks(110)

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2 lytic lesions sounds like a metastatic origin

The most common locations for bone metastasis: Prostate, Breast > Kidney, Thyroid, Lung

Lead (PB) K e T t L e

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lokotriene FA2020 p223 +

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submitted by ∗lamhtu(139)

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Stem should maybe say some lesions are lytic and some are sclerotic. Breast mets to bone is mixed type according to FA? If you go off the mets being purely lytic, one could think thyroid carcinoma is the correct primary tumor.

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lae thats also what I thought +11

pg32 Yeah I didn't pick breast for the same reason. Then I didn't pick thyroid because I doubt serologic studies would be normal in thyroid cancer (if you check T3/T4 and TSH). So I went with avascular necrosis -_- +3

lynn in the FA index, the only things listed under lytic bone lesions are adult T cell lymphoma, langerhan histiocytosis, and multiple myeloma. Obviously there's more than that but those might be the main ones we need to know. You could also say that a giant cell tumor is also technically lytic, considering they describe it as "osteoclastoma." Idk. I thyroid but looking at FA, none of the thyroid carcinomas describe metastatic lytic lesions. Medullary carcinoma might be the one to confuse you, but it secretes calcitonin which inhibits osteoclasts, so it shouldn't cause resorp or lytic lesions. Right?? +1

prp5c just a different view - I was between avascular necrosis and metastatic carcinoma, but ended up going with metastatic carcinoma because I figured avascular necrosis of the lumbar and thoracic region would be hard since you'd have the artery of Adamkiewicz as a dual supply to the vertebrae? +1

baja_blast I only picked breast over thyroid because it specified "metastatic". I agree this definitely threw me off. According to Dr Sattar, breast cancer causes "mixed lytic/blastic lesions". Most all other bone mets are lytic w/ the exception of the prostate which causes blastic mets. +

jaramaiha The likelihood of avascular necrosis specifically at T-10 and L-1 while skipping T-11 & T-12 didn't make any sense to me. Plus no Hx of trauma. I can't remember which Uworld question, but I remember a few of them describing the flow of metastatic breast cancer through the intercostal veins and can get access into the vertebral venous plexus and eventually spread to vertebra and brain. +

heenaasnani When i was on this question, i was confused between Thyroid and Breast too. However, breast can have both lytic and blastic lesions doesn't necessarily mean that it will have both at the time of presentation. It can have only lytic, only blastic or can also have both. So in my opinion, we should always choose the most common answer because which goes by the sequence of Prostate> Breast> Thyroid, Lung, Kidney. These were purely my thoughts. Correct me if i am wrong. I hope it helped. +

heenaasnani answer which* +

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submitted by ∗lae(33)

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uptodate says it can cause only osteolytic lesions too, and because it says "most likely" and breast cancer is the most common cancer in women, it is breast ...

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pelparente Yah ^ this is why I put breast over thyroid. +2

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submitted by ∗tekkenman101(19)

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A middle aged woman with multiple thoracic and lumbar bone lesions and no other medical history should automatically make you think metastatic breast cancer. Don't complicate things.

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