Hi all, so I just finished the nbme 13 and have some questions. There might be some redundancy from previous posts, but I would really appreciate your feedback.
1. An autopsy is done on a 46 yr old woman who died of adenocarcinoma of the colon. Exam of the neck show a 5 cm rounded mass next to the bifurcation of the carotid artery. A section of the mass is shown in the photomicrograph. Immunohistochemistry of the section is positive for synaptophysin, chromagranin and neuron-specific enolase. Electron microscopy shows numerous electron-dense, membrane-bound neurosecretory granules. Exam of the adrenal glands shows no masses. Which of the following is the most likely diagnosis?
View attachment 200826
A. metastatic colonic adenocarcinoma
B. metastatic squamous cell carcinoma of the larynx
C. papillary carcinoma of the thyroid gland
D. paraganglioma
E. parathyroid adenoma
--> + chromogranin, I was thinking carcinoid and went for A, but it's wrong.
2. A 33 yr old woman who is right-handed is brought to the physician b/c of a 3 day hx of progressive weakness and numbness of her arms and legs. Neurologic exam shows proximal and distal weakness of the upper and lower extremities. There is areflexia. Sensation to vibration and joint position is decreased in the fingers and toes. Nerve conduction studies show a slow conduction velocity in the median, ulnar, peroneal, and tibial nerves. These electrophysiologic findings most likely indicate impaired function of which of the following ion channel?
A. neurotransmitter gated Ca2+ channels
B. neurotransmitter gated K+ channels
C. neurotransmitter gated Na+ channels
D. voltage gated Ca2+ channels
E. voltage gated K+ channels
F. voltage gated Na+ channels
--> Arent these symptoms due to hypocalcemia??? I went for A and got it wrong, so is it D?