HY lecture notes:
3M + midline abdominal mass + HTN + eye movements; Dx? –> neuroblastoma; eye movements = opsoclonus-myoclonus syndrome (seen in neuroblastoma).
3M + midline abdominal mass + HTN + eye movements; next best step in Mx? –> USMLE wants “urinary homovanillic acid (HVA) and vanillylmandelic acid (VMA)”; these are catecholamine breakdown products. In contrast, for pheochromocytoma in adults, the answer is “urinary + serum metanephrines”; these are also catecholamine breakdown products.
If they ask imaging for neuroblastoma; answer? –> meta-iodobenzylguanidine scan (mIBG-avid), which can image >90% of neuroblastomas.
Neonatal male + midline abdo mass; Dx? –> posterior urethral valves (PUV); most common genitourinary abnormality in neonatal males.
PUV; next best step in diagnosis + Tx? –> voiding cystourethrogram to Dx; Tx = surgery.
3M + painless flank mass + no other info; Dx? –> Wilms tumor.
6M + painless flank mass + seizure + MRI of brain shows periventricular nodules; Dx? –> Tuberous sclerosis with renal angiomyolipoma.
Anything else about Wilms tumor? –> increased incidence in horseshoe kidney in Turner syndrome.
Horseshoe kidney key point? –> not only increased risk of Wilms tumor, but the kidney gets caught under the IMA.
What is WAGR complex? –> Wilms tumor, Aniridia, Genitourinary malformation, Retardation; caused by WT1 gene mutation.
What is Denys-Drash syndrome? –> Wilms tumor + male pseudohermaphroditism (secondary sex characteristics are female; primary sex characteristics are male); caused by WT1 gene mutation.
What is Beckwith-Wiedemann syndrome? –> Wilms tumor + neonatal hypoglycemia + macrosomia / macroglossia + hemihypertrophy +/- omphalocele; caused by WT2 gene mutation.
AR vs AD polycystic kidney disease? –> ARPKD is chromosome 6 and a pediatric condition; it’s associated with hepatic fibrosis. ADPKD is chromosome 16 and presents in 30s or 40s; associated with HTN and circle of Willis saccular (berry) aneurysms.
