Weekly Case

Title : Case 576

Age / Sex : 58 / F


Chief complaint: Left wrist pain for 2 days

What is your impression?

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

Courtesy of Yun Sun Choi, MD, Eulji Hospital, Eulji University



Discussion


Answer: Osteoid osteoma of the capitate


 


Findings:


Anteroposterior radiograph of the left wrist shows a sclerosis area in the distal pole of the capitate. Coronal T1-weighted FSE MR image shows a well-circumscribed lesion with a central low signal in the capitate. On coronal and axial fat-suppressed T2-weighted FSE MR images, this lesion shows a low signal center (calcified nidus) surrounded by the thin high signal rim in the volar aspect of capitate. There is edema in the remaining capitate bone, as well as joint effusion and synovitis in the midcarpal and carpometacarpal joints.


 


Differential Diagnosis:



  1. Osteoblastoma

  2. Osteonecrosis

  3. Osteomyelitis

  4. Bone island


 


Diagnosis: Osteoid osteoma of the capitate


 


Discussion:


Osteoid osteoma of the wrist is rare with reported incidences ranging between 2.8 and 10.2%. In the carpal bones, an osteoid osteoma is commonly found in the capitate or the scaphoid and usually arises in the medullary spongiosa. The diagnosis of an osteoid osteoma of the wrist and hand is often delayed because typical clinical (e. g. responding to nonsteroidal anti-inflammatory drugs) and radiological findings are lacking. The latter is due to the fact that either the reactive sclerosis of the adjacent bone is lacking or the nidus itself appears as an area of extensive sclerosis more than of radiolucency. This explains why approximately 25% of these tumors are not detected on radiographs, making osteoid osteoma of the wrist a difficult lesion to diagnose. MRI shows a well-circumscribed lesion in the capitate bone. The focal nature of the lesion and the marked enhancement of the non-sclerotic parts of the nidus after contrast agent injection favors a highly vascularized tumorous lesion. The dense calcification of the nidus is hypointense on all sequences. The presence of an adjacent bone marrow edema is also well known in osteoid osteoma and may be due to elevated prostaglandin levels in the nidus which, together with a stimulation of bradykinin, leads to an increased permeability of the capillaries. Occasionally, the aggressive appearance of the edema can be misleading. Thin-slice CT scan is considered as the reference imaging technique for the diagnosis of osteoid osteoma and is particularly useful when the nidus is hidden by complex anatomy.


 


References:



  1. Murray PM, Berger RA, Inwards CY. Primary neoplasms of the carpal bones. J Hand Surg Am. 1999;24(5):1008-1013

  2. Al Shaikhi A, Hébert-Davies J, Moser T, Maillot E, Danino AM. Osteoid osteoma of the capitate: a case report and literature review. Eplasty. 2009;9:e38

  3. Kreitner KF, Löw R, Mayer A. Unusual manifestation of an osteoid osteoma of the capitate. Eur Radiol. 1999;9(6):1098-1100


 



Correct Answer
Total applicants 47 Correct answers 24
Name Institution
전성희 전문의
박지원 전문의
장성원 중앙보훈병원, 전공의
김창현 전문의
서현주 전문의
이은채 전문의
권소이 전문의
지숙경 삼성서울병원, 전문의
김형민 전문의
윤유성 삼성서울병원, 전문의
김현진 전공의
김현영 분당서울대학교병원, 전문의
이혜란 전문의
이영선 전문의
이성욱 단국대병원, 전공의
조신영 웰튼병원, 전문의
이승현 국민건강보험 일산병원, 전문의
이승민 전문의
김보람 전문의
박준동 뿌리병원, 전문의
장민영 국민건강보험공단 일산병원, 전문의
한유비 전문의
이지현 삼성서울병원, 전문의
최희석 전병원, 전문의


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