Age / Sex : 32 / M

Chief complaint: incidental mass lesion

1) What is your impression?

Two weeks later, you can see the final diagnosis with a brief discussion of this case.

(Quiz는 quiz일 뿐이오니 답안은 한개만 보내주시기 바라오며, 복수의 답안을 보내주시는 분은 정답이 포함되어 있더라도 부득이 semi-correct answer로 처리토록 하겠습니다.)

Courtesy: 이준우 (Joon Woo Lee), 분당서울대병원 (Seoul National University Bundang Hospital)

osteochondroma, arising from right transverse process of T6

Discussion

Findings:

MRI: Multilobular high SI lesion at right paravertebral space, continuous to underlying right 6^th transverse process. There is no enhancement on postcontrast image.

Differential Diagnosis:

Diagnosis: osteochondroma, arising from right transverse process of T6

Discussion: Osteochondroma is a cartilage-covered osseous excrescence arising from bone surface, which may be a developmental lesion, rather than true neoplasm. There are two types of the lesion including pedunculated and sessile types. Cartilage cap usually shows iso- to low SI on T1 weighted images and high SI on T2 weighted scan. When the thickness of cartilage cap is greater than 1.5cm, malignant transformation may be suspected and more common in hereditary multiple exostosis.

References: Bone and joint imaging, 3^rd ed. Elsevier. P 1146-54.