NBME 16 Answers ↦
Another reason this is small cell lung cancer is the weakness of the proximal upper and lower extremities while also having augmentation (increasing) of strength with repetitive stimulation. This is characteristic of Lambert-Eaton myasthenic syndrome [where strength increases with stimulation; opposite of myasthenia gravis]. Lambert-Eaton can be caused by a paraneoplastic syndrome of small cell lung cancer (FA2020 p228 and 472)
What about the fact that it is a single well-demarcated mass. Wouldnt metastatic cancer present as multiple masses? This made me think primary brain cancer.
@passplease I originally thought this way too and it fucked me.
I think the easiest way is elimination + staining.
Pt is an adult - eliminate neuroblastoma, ependymoma as both are more common in kids
Pt is not immunocompromised - eliminate CNS lymphoma
GBM does not stain positive for cytokeratin, chromogranin, synaptophysin - eliminate GBM
Left with Small cell carcinoma