NBME 22 Prostate adenocarcinoma (NBME Answers)

Retired NBME 22 Answers

nbme22/Block 2/Question#16 (reveal difficulty score)
A 60-year-old man is brought to the emergency ...
Prostate adenocarcinoma 🔍 / 📺 / 🌳 / 📖
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submitted by ∗cocoxaurus(59)

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Almost got tricked by this one because osteosarcoma also causes osteoblastic lesion. Osteosarcoma most commonly metastasizes to lungs though.

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impostersyndromel1000 This was in pathoma, he said prostate cancer causes osteoblastic lesions and "the board examiners really want you to know that". also following the potential site of mets helps choose the answer +2

snripper Also, osteosarcoma is less common in the elderly, more common in males <20 y/o (per F.A 2020) +2

homersimpson Osteosarcoma causes lytic bone lesions @cocoxarus +

chaosawaits I definitely overthought this one to death. I had prostate adenocarcinoma, but then reread it to make sure I wasn't missing anything. The normal referenced labs made me reconsider. So I chose osteosarcoma. If anyone could explain the normal labs (no elevated ALP), I'd appreciate it. +1

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submitted by lisa(0)

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Hints. His age + Multilple blastic lesion pointing out at metastasis. Negative protein electrophoresis ruled out Multiple myeloma

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drjungly All primary bone cancer - mc seen in age b/t 20-40 peak at 25. Prostate adenocarcinoma - mc seen age >50 yr old. Source-FA 2018 +3

asharm10 Sometimes instead of osteoblastic they say osteosclerotic that's synonym of Osteoblastic. For multiple myeloma it's always osteolytic. +3

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submitted by nootnootpenguinn(9)

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Why are his labs normal?

Protein electrophoresis is to r/o MM. What are the others trying to rule out? Also, if it was prostate adenocarcinoma, wouldn't there be elevated PSA in the urine (which might result abnormal UA)?

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lsp1992 Urinalysis provides a microscopic examination of urine, which would tell you about the presence of RBC, WBC, casts, crystals, epithelial cells, and a chemical test for nitrites, bili, urobilinogen, ph, specific gravity, proteins, glucose, blood, and ketones. PSA is a specific protein that would be found in the blood, and a lab test that would have to be ordered specifically. +1

chaosawaits Does the same logic apply for no report of elevated ALP? +

l0ud_minority So chemistry profiling is supposed to mean a BMP? This could be interpreted just as easily as a CMP which would give you Alk Phos. Poorly written question. +

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