Embryology USMLE Step 1 Practice Question
A 3-month-old boy is brought to the emergency department with failure to thrive, irritability, and pallor. On examination, a firm abdominal mass is palpable below the right costal margin. Vital signs show tachycardia (HR 148/min), tachypnea (RR 35/min), and hypertension (BP 102/68 mmHg). Laboratory studies reveal elevated urinary vanillylmandelic acid and plasma norepinephrine. Abdominal ultrasound demonstrates a 5.5-cm heterogeneous mass arising from the right adrenal gland with areas of cystic degeneration. Histopathology shows immature sympathetic neurons and ganglion cells with minimal mitotic activity. There is no evidence of metastatic disease. From which embryologic origin did this tumor arise?
Answer choices
- AMesodermal cells of the adrenal cortex derived from the urogenital ridge
- BEndodermal cells from the dorsal mesentery of the foregut
- CEctodermal cells from the basal lamina of the neural tube
- DNeural crest cells that migrated to form the adrenal medullaCorrect answer
- ESplanchnic mesoderm that differentiated into chromaffin tissue
- FEndodermal cells from the coelomic epithelium
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