WBR0202

Author	[[PageAuthor::Ayokunle Olubaniyi, M.B,B.S [1]]]
Exam Type	ExamType::USMLE Step 1
Main Category	MainCategory::Pathology
Sub Category	SubCategory::Oncology
Prompt	[[Prompt::A 12-year-old boy comes to the health center because he has had persistent fever and pain in his right leg for the past 2 months. He says that he recently added jogging to his weight-lifting workouts, and he started running 5 miles per day 2 weeks ago. He is 5 ft 7 inches tall and weighs 60kg. On physical examination, he has moderate tenderness over the diaphysis of the right leg. Additional tests were done which revealed a small, round, blue cell tumor, and a translocation between chromosomes 11 and 22. X-ray of the hip will most likely show which of the following?]]
Answer A	AnswerA::“Double bubble” sign
Answer A Explanation	AnswerAExp::Double bubble sign is a feature of Osteoclastoma. The age range is between 20-40 years and it is usually located at the epiphysis of long bones.
Answer B	AnswerB::Codman’s triangle or sunburst appearance pattern
Answer B Explanation	AnswerBExp::This is a feature of Osteosarcoma. It affects men between ages 10-20 years. It is usually around the metaphysis of long bones.
Answer C	AnswerC::“Onion-skin” appearance
Answer C Explanation	AnswerCExp::The “Onion-skin” appearance is a pathognomonic feature observed in Ewing's sarcoma.
Answer D	AnswerD::Glistering mass within the medullary cavity
Answer D Explanation	AnswerDExp::This is a feature of Chondrosarcoma. It affects men between the ages 30-60. It is commonly found in the pelvis, spine, scapula, tibia, and femur.
Answer E	AnswerE::Normal findings
Answer E Explanation	AnswerEExp::The presence of a small, round, blue cell tumor, and a translocation between chromosomes 11 and 22 are not normal in any individual.
Right Answer	RightAnswer::C
Explanation	[[Explanation::Ewing’s sarcoma is a malignant small, round, blue cell tumor in which cancer cells are found in the bone or in soft biological tissue. It is a rare disease commonly prevalent among boys less than 15 years of age. The most common locations are: pelvis, femur, humerus, ribs and clavicle (collar bone). The characteristic appearance on X-ray is the “Onion-skin” appearance. Treatment is chemotherapy. Educational Objective: References: ]]
Approved	Approved::Yes
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