WBR0930

Author	PageAuthor::William J Gibson
Exam Type	ExamType::USMLE Step 1
Main Category	MainCategory::Pathology, MainCategory::Pharmacology
Sub Category	SubCategory::Hematology
Prompt	Prompt::A 35 year old man is treated for acute promyelocytic leukemia with a sustained course of arsenic trioxide and All-trans-retinoic acid. If he develops a secondary malignancy due to this therapy, which of the following is most probable?
Answer A	AnswerA::Gastric cancer
Answer A Explanation	AnswerAExp::'''Incorrect:''' Gastric cancer can occur as a result of nistrosamine exposure. Nitrosamines are carcinogenic chemical compounds present in various foods, notably smoked meats.
Answer B	AnswerB::Leukemia
Answer B Explanation	AnswerBExp::'''Incorrect:''' Leukemia can occur as a result of previous genotoxic chemotherapy, such as alkylating agents.
Answer C	AnswerC::Transitional cell carcinoma of the bladder
Answer C Explanation	AnswerCExp::'''Incorrect:''' Transitional cell carcinoma of the bladder is associated with previous exposure to napthylamine compounds (used in the manufacture of aniline synthetic dyes).
Answer D	AnswerD::Hepatocellular carcinoma
Answer D Explanation	AnswerDExp::'''Incorrect:''' Hepatocellular carcinoma is caused by exposure to aflatoxin.
Answer E	AnswerE::Angiosarcoma
Answer E Explanation	AnswerEExp::'''Correct:''' Angiosarcoma is a potential late complication of exposure to arsenic.
Right Answer	RightAnswer::E
Explanation	[[Explanation::Acute promyelocytic leukemia (APML) is rare subset of acute myeloid leukemia (AML). APML is characterized by a chromosomal translocation involving the retinoic acid receptor-alpha gene on chromosome 17 (RARA). These cells undergo a differentiation arrest, which can be reversed with all-trans retinoic acid. Arsenic is thought to act by inhibiting the enzyme thioredoxin reductase.Histologically, APML is notable for leukemic cells containing rod-like cytoplasmic inclusions called “Auer rods”. Treatment of APML can precipitate release of these inclusion and cause DIC. Educational Objective: Angiosarcoma is a potential late complication of exposure to arsenic. References: First Aid 2013 page 223 First Aid 2012 page 255 http://ctdbase.org/detail.go?type=relationship&chemAcc=C006632&diseaseAcc=D006394&diseaseDb=MESH The carcinogenicity of arsenic. Pershagen G. Environ Health Perspect. 1981 Aug;40:93-100. Review. PMID: 7023936 Educational Objective: References: ]]
Approved	Approved::Yes
Keyword	WBRKeyword::Cancer, WBRKeyword::Chemotherapy, WBRKeyword::Side effect, WBRKeyword::Leukemia, WBRKeyword::Acute promyelocytic leukemia, WBRKeyword::Toxin
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