n Case Report Chondroblastoma With Secondary Aneurysmal Bone Cyst of the Capitate EIICHI SATO, MD, PHD; JIRO ICHIKAWA, MD, PHD; TAKASHI ANDO, MD, PHD; NOBUTAKA SATO, MD; TOMONORI KAWASAKI, MD, PHD; HIROTAKA HARO, MD, PHD abstract Full article available online at Healio.com/Orthopedics Chondroblastoma is a benign tumor that typically arises in the epiphysis of a long bone. There have been only 2 reported cases of chondroblastoma involving the cap- itate. This is the first report of chondroblastoma with secondary aneurysmal bone cyst involving the capitate. A 33-year-old man presented with a 3-year history of pain and swelling of the right wrist. Radiography as well as computed tomography Figure: Radiograph showing a lytic lesion in the showed a radiolucent area and no matrix calcification within the capitate. Magnetic capitate. resonance imaging revealed a homogeneous signal that was low on T1-weighted images and high on T2-weighted images and showed only slight enhancement. On the basis of imaging findings, the authors chose excisional biopsy. The bone tumor in the capitate was explored through a dorsal approach by dividing the extensor tendons. After repeated curettages, bone graft substitute using allograft bone was packed into the capitate. Histologically, the authors diagnosed this tumor as a chon- droblastoma with a secondary aneurysmal bone cyst. At the final 2-year follow-up, there was evidence of bone union, full range of motion, and recovery and no evi- dence of recurrence. Although the recurrence of chondroblastoma is occasionally reported, the principal treatment is intralesional curettage and bone graft. High- speed burring, phenol, bone cement, and cryosurgery have been reported to reduce local recurrence. Complete excision of the carpal bone seems to be overtreatment. The authors are from the Department of Orthopaedic Surgery (ES, JI, TA, NS, HH) and the Department of Pathology (TK), Graduate School of Medicine, University of Yamanashi, Yamanashi, Japan. The authors have no relevant financial relationships to disclose. Correspondence should be addressed to: Jiro Ichikawa, MD, PhD, Department of Orthopaedic Surgery, Graduate School of Medicine, University of Yamanashi, 1110 Shimokato, Chuo, Yamanashi 409-3898, Japan ([email protected]). Received: June 21, 2013; Accepted: October 9, 2013; Posted: May 14, 2014. doi: 10.3928/01477447-20140430-63 e500 ORTHOPEDICS | Healio.com/Orthopedics n Case Report hondroblastoma is a benign tumor that accounts for approximately C1% of all primary bone tumors and typically arises in the epiphysis of a long bone.1 Only 2 cases of chondroblastoma of the capitate have been published. One report showed the frequency of primary bone tumors, including chondroblastoma, in carpal bones.2 Another report showed sus- pected tuberculosis of the capitate, and the A B resultant histopathologic findings altered Figure 1: Radiograph showing a lytic lesion in the capitate (A). Coronal computed tomography image the diagnosis to chondroblastoma without showing a lytic lesion in the entire capitate with pathological fracture (B). secondary aneurysmal bone cyst (ABC) formation.3 This report describes the first case of chondroblastoma with secondary ABC change of the capitate that was treated successfully with curettage (intralesional resection) and bone graft substitute. A B C CASE REPORT Figure 2: Magnetic resonance imaging of the lesion. T1-weighted (A), T2-weighted (B), and enhanced T1- A 33-year-old man had a 3-year history weighted (C) images. Magnetic resonance imaging showed low signal intensity on enhanced T1-weighted of pain and swelling of the right wrist. The images and high signal intensity on T2-weighted images, as well as rim enhancement on enhanced T1- weighted images. patient had no history of trauma. Physical examination of the wrist showed swell- ing, local heat and tenderness, and range of sal cortex of the capitate was easily cut by ically, tumor cells were positive for S-100 motion (ROM) that was 60° of flexion and scalpel, and the discharge of fluid inside of protein. Based on these pathologic findings, 30° of extension. Neurologic findings were bone was seen after removal of the cortex. the tumor was identified as a chondroblas- normal. Radiographs showed a radiolucent High-speed burr was not used because of toma with secondary ABC change. Two area within the capitate (Figure 1A). Chest the pathological fracture. Instead, many cu- years after surgery, there was evidence of radiograph showed no evidence of metasta- rettages by curettes and washes by water jet bone union, full ROM, and recovery, and no sis. Computed tomography showed similar were radically repeated. Finally, bone graft evidence of recurrence (Figure 4). findings as the radiograph and no matrix cal- substitute using allograft bone was packed cification inside of bone. The cortex showed into the capitate. Histologically, the curet- DISCUSSION discontinuity that suggested pathological ted specimen from the capitate bone of the Chondroblastoma is a benign tumor fracture (Figure 1B). Magnetic resonance right hand showed mononuclear tumor cells commonly located in long bones, in- imaging showed a homogeneous signal with (chondroblasts) in a solid growth pattern, cluding the humerus, tibia, and femur. low intensity on T1-weighted images (Fig- with polygonal, somewhat eosinophilic cy- Chondroblastoma involving the hands is ure 2A) and high intensity on T2-weighted toplasm and round to ovoid, indented, or very rare. In a review of 26,800 primary images (Figure 2B) without fluid-fluid lev- lobulated nuclei and evenly distributed chro- bone tumors, Murray et al2 reported pri- els. Enhanced T1-weighted images (Figure matin (Figures 3A-3C). Nucleoli were not mary bone tumors of the carpus in only 2C) showed only slight enhancement at prominent, and mitotic figures were uncom- 44 cases (0.16%). Among these 44 cases, the edge of the capitate, with surrounding mon. Production of a cartilaginous matrix there were 11 patients with osteoid os- inflammation. Based on these findings, the that showed ossification and focal calcifica- teoma (25%), 6 patients with osteoblas- differential diagnosis included benign cystic tion was also identified (Figure 3B). The toma (13.6%), and 6 patients with chon- tumors such as aneurysmal bone cyst, chon- tumor cells were accompanied by randomly droblastoma (13.6%). Of the 6 cases of droblastoma, and giant cell tumor. Based on distributed osteoclastic-type multinucleated chondroblastoma, 3 were located in the the differential diagnosis, excisional biopsy giant cells (Figures 3A-3B). Hemorrhagic scaphoid, with 1 each in the capitate, lu- was performed. The bone tumor in the capi- findings with hemosiderin pigmentation nate, and triquetrum.2 No details about tate was explored through a dorsal approach (Figure 3A) and cystic formation (Figure histopathology, treatment, or recurrence by dividing the extensor tendons. The dor- 3D) were also observed. Immunohistochem- rate were given. Mangini3 reported 1 case MAY 2014 | Volume 37 • Number 5 e501 n Case Report Figure 4: Radiograph taken at the final 2-year follow-up. is the preferred treatment for chondro- blastoma in the hands or wrist. However, Daly et al15 reported that chondroblastoma of the hamate was treated with complete excision. Although 1 treatment option is complete excision of the carpal bone, this approach seems to be overtreatment because chondroblastoma is believed to be less aggressive in the carpal bones. In Figure 3: Histology of the lesion. Hematoxylin and eosin staining showing round or polygonal cells with addition, considering the young age at an oval to round nucleus with eosinophilic cytoplasm (A [original magnification, ×100], B [original magni- presentation (10-20 years),1 resulting os- fication, ×100], C [original magnification, ×400]). The aneurysmal bone cyst component (D [hematoxylin teoarthritis in the carpometacarpal joint and eosin, original magnification, ×40]). must be considered in the treatment deci- sion. Furthermore, surgery of the midcar- of chondroblastoma of the capitate associ- ABC change was a risk factor for recur- pal and radiocarpal joints may result in ated with suspicion of tuberculosis. This rence. Some cases of metastasis have been loss of grip power and hand function. The case was treated successfully with only reported,8,10 and because of its aggressive authors suggest that the first treatment op- curettage without bone graft, and the his- biologic behavior, care should be taken in tion for chondroblastoma in all locations topathologic findings showed no evidence the treatment of chondroblastoma around should be only curettage and allograft or of secondary ABC change. To the authors’ the hip and pelvis. In contrast, to the au- artificial bone graft. knowledge, there has not been a previous thors’ knowledge, unlike chondroblas- report of chondroblastoma with second- toma around the hip, there have been no REFERENCES ary ABC change of the capitate treated by reports of metastases from chondroblas- 1. Kurt AM, Unni KK, Sim FH, McLeod RA. curettage and bone graft substitute. tomas originating in the hands or wrists. Chondroblastoma of bone. Hum Pathol. 1989; 20(10):965-976. The recurrence rate for chondroblas- The principal treatment of chondro- 4,5 2. Murray PM, Berger RA, Inwards CY. Primary toma is reported to be 10% to 32%, and blastoma is intralesional curettage and neoplasms of the carpal bones. J Hand Surg secondary ABC change is believed to be a bone graft. Suneja et al10 reported that Am. 1999; 24(5):1008-1013. risk factor for local recurrence.6,7 On the of 52 patients treated with only intral- 3. Mangini U. Benign chondroblastoma local- other hand, Sailhan et al5 reported that esional curettage, 7 (13.2%) patients had ized in the capitate bone: a case report. Bull Hosp Joint Dis. 1964; 25:50-56. epiphyseal location, not secondary ABC a local recurrence. High-speed burring, 4. Springfield DS, Capanna R, Gherlinzoni F, change, was a risk factor for recurrence. phenol, bone cement, and cryosurgery Picci P, Campanacci M. Chondroblastoma: a In addition, various authors have suggest- were recommended to reduce local re- review of seventy cases.