Weekly Case

Title : Case 685

Age / Sex : 47 / M

Chief complaint : Palpable hand mass

What is your diagnosis?

Two weeks later, you can see the final diagonosis with a brief discussion of this case (Please submit only one answer).

Courtesy : 
박찬규, Chankue Park, 양산부산대학교병원, Pusan National University Yangsan Hospital



Enchondroma protuberance



About 1.1 x 1.7 x 1.0cm sized exophytic mass in the right 3rd metacarpal bone.

- with intramedullary location and cortical expansion

- with lobulated shape and circumscribed margin

- with peripheral and septal enhancement


Differential Diagnosis:

Osteochondroma, Periosteal chondroma



Enchondroma protuberans (EP)

- rare form of enchondroma which demonstrates exophytic growth outside the margins of the bony cortex

- common site: hand (usually in the phalanges or metacarpal bones) > ribs > long bones of the arm


Radiologic findings

- Radiographs of EP typically show a well-defined geographic, osteolytic intramedullary lesion that may have poorly defined matriceal calcification combined with a cortical defect and well-defined round soft-tissue expansion. Although EP can usually be diagnosed using only radiographs, some cases could not be positively diagnosed using radiography alone because it did not reveal the protruded mass or the cortical defect. The MR images clearly delineated the connection between the intramedullary lesion and the exophytic protrusion through the cortical defect as well as the tumors themselves, which resulted in the diagnosis of EP.


Differential diagnosis

 - Osteochondroma: presence of a cartilage cap with underlying trabecular bone

 - Periosteal chondroma: periosteal location and lack of communication of the lesion with the medullary canal


Tip. Enchondroma typically appears as an intramedullary lucent lesion without mineralization at hand. However, if bone mass of the hand appears to be an exophytic mass with the characteristics of a chondroid tumor, consider enchondroma protuberans.



HS Kang, JM Ahn, Y Kang. Oncologic imaging: Bone tumors. Springer. 2017

A Kord, B Kravis, S Rsotami. Enchondroma protuberans of the hand: A case report. Radiology case report. 2020 15(7):943-946

An YY, Kim JY, Ahn MI. Enchondroma Protuberans of the hand. Am J Roentgenol. 2008 190(1):40-4.

Correct Answer
Total applicants 33 Correct answers 10
Name Institution
윤유성 순천향대 부천병원, 전문의
장민영 국민건강보험공단 일산병원, 전문의
김동언 서울아산병원, 전문의
조영민 전문의
이승보 서울아산병원, 전문의
권기언 서울아산병원, 전문의
이민욱 충남대학교병원, 전문의
김성진 365병원, 전문의
백승진 분당차병원, 전공의
심상우 서울아산병원, 전문의
Semi-Correct Answer
Total applicants 33 Semi-Correct answers 9
이규정 국군대전병원, 전문의
여현정 전문의
강지희 전문의
최수연 전문의
박선영 한림대학교 성심병원, 전문의
이혜란 전문의
김동수 전공의
김현진 서울성모병원, 전공의
윤나연 전공의