288) A 38 year old caucasian man is seen in the office during a routine follow up visit. His past medical history is significant for testicular non-seminomatous germ cell tumor diagnosed 9 months ago and was treated with radical orchiectomy of left testicle and chemotherapy. He completed chemotherapy 6 months ago and achieved a complete response. His tumor markers and imaging studies 3 months after completion of therapy were normal. He complains of decreased sexual drive and energy. He denies smoking tobacco or alcohol. He uses Marijuana on a daily basis but quit 2 months ago. His family history is unremarkable. Physical examination shows absent left testicle. Rest of the physical is normal. Serum alpha-fetoprotein is normal. Beta HCG is elevated at 15U/L ( Normal < 5 U/L) . A chest X-ray , CT scan of the abdomen and pelvis are normal. His routine laboratory investigations including complete blood count are within normal limits. Which of the following is most likely reason for his elevated Beta-HCG?
A) Recurrent tumor
B) Marijuana Use
C) Hypogonadism
D) Chemotherapy effect
E) Hyperthyroidism
Filed under: Uncategorized, USMLE Test Prep | Tagged: Archer endocrinology, Archer oncology, ARCHER UROLOGY, internal medicine board review, serum testosterone, STEP 3 ONCOLOGY, usmle step 3 endocrinology, USMLE STEP 3 ONCOLOGY, usmle step 3 urology |
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A
a
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B) Marijuana Use
A…….. β-HCG is an excellent tumor marker for the monitoring of germ cell tumors.
Marijuana use? No, he stop marijuana 2 month ago and stil if he si using marijuana, how we can test marijuana with bHCG, even false positive. No I do not think so….false positive b HCG we can see in IgA deficiency (up to 30% of the IgA deficient sera analysed lead to a false positive pregnancy test), but no marijuana.
A
C) Hypogonadism
Slight increase in HCG is due to Hypogonadism after treatment of testicular cancer. Slightly increased hCG concentrations have occasionally been misinterpreted to indicate a relapse, leading to inappropriate chemotherapy.
Excellent!
In pts like this, elevated hCG could be due to tumor relapse, hypogonadism or marijuana use.
If the pt uses marijuana make them abstain form it for a while and retest, hcg should be low after abstaining.
Hypogonadism causes a falsely elevated hcg because in hypogonadism (due to chemo and orchiectomy) testostrone is low and LH is high. LH cross-reacts with the substance used to test for hcg so since LH is high, titer shows high hcg too. To r/o hypogonadism out, if you give pt testosterone treatment the hcg will normalize because LH should normalize too. If it does not happen, then the cause of elevated hcg is tumor relapse