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Age / Sex : 12 / F
Chief complaint: right hand pain for 2 months
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: 최진하/이민희(Choi Jinha / Lee Min Hee), 서울아산병원(Asan Medical Center)
Diagnosis: Enchondroma protuberans
Discussion
Findings:
Plain radiograph of a right
hand (AP projection) shows a geographic osteolytic intramedullary lesion with a
protruding bony mass in right 4th metacarpal bone. An intramedullary bony
lesion is expansile with endosteal scalloping and cortex is remodeled. T1-weighted,
fat-suppressed T2-weighted coronal MR images show a hyperintense mass within
the medullary cavity with contiguous soft-tissue extension. Contrast-enhanced T1-weighted
coronal MR image with fat-suppression shows peripheral and septal enhancement within
the mass.
Diagnosis
Enchondroma
protuberans
Differential
Diagnosis:
Low grade chondrosarcoma
Osteochondroma
Periosteal chondroid tumor
Discussion:
Enchondroma
protuberans is a rare benign chondromatous tumor that arises in the medullary
canal, forming an exophytic mass in the surrounding soft tissue. The presence
of an exophytic mass distinguishes enchondroma protuberans from conventional
enchondroma.
Typical
radiographic finding is a well –defined geographic, osteolytic, intramedullary
lesion that may have a speckled calcification combined with a cortical defect
and well-defined round soft tissue expansion. Sometimes plain radiography alone
does not show the protruded mass or the cortical defect. MR images clearly
delineate the connection between the intramedullary lesion and the exophytic
protrusion through the cortical defect as well as the tumors themselves, which enables
the diagnosis of enchondroma protuberans.
The
differential diagnosis includes osteochondroma, chondrosarcoma, and periosteal chondroid
tumors. The absence of a cartilage cap with underlying trabecular bone can exclude
osteochondroma. Periosteal chondroma develops subperiosteally and erodes the
underlying cortex, however, endosteal
surface may remain intact. Chondrosarcoma and enchondroma protuberans have
similar features, such as focal cortical defect and adjacent soft tissue mass
formation.
References:
1. An YY, Kim JY, Ahn MI,
Kang YK, Choi HJ. Enchondroma Protuberans of the hand. Am J Roentgenol. 2008
Jan;190(1):40-4.
2. Slesarenko YA, Sampson
SP, Gould ES, Dagum AB. Recurrent enchondroma protuberans: a case report. J
Hand Surg Am. 2005 Nov;30(6):1318-21.
3. Kita K, Masada K, Yasuda
M, Takeuchi E. Enchondroma protuberans of the phalanx: a case report. J Hand
Surg Am. 2003 Nov;28(6):1052-4.
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