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Treatment of chondroblastoma of the calcaneus with a secondary aneurysmal bone cyst using endoscopic curettage without bone grafting
Case Report
Treatment of Chondroblastoma of the Calcaneus With a Secondary Aneurysmal Bone Cyst Using Endoscopic Curettage Without Bone Grafting Takanobu Otsuka, M.D., Masaaki Kobayashi, M.D., Masato Yonezawa, M.D., Fumiaki Kamiyama, M.D., Yasusi Matsushita, M.D., and Nobuo Matsui, M.D.
Abstract: Chondroblastoma is a relatively rare benign bone tumor. Approximately 7% of chondroblastomas occur in the calcaneus, and 17% of chondroblastoma associated with cystic lesions. We report a case of a chondroblastoma in the calcaneus with a secondary aneurysmal bone cyst treated successfully by endoscopic curettage without bone grafting. New bone formation is facilitated by minimal damage to the bone and soft tissue. The cosmetic results of this procedure are good. Two years later, the patient is asymptomatic with no radiographic evidence of recurrence. Endoscopic curettage without bone grafting is a promising new treatment for chondroblastoma. Key Words: Chondroblastoma—Aneurysmal bone cyst—Endoscopic curettage—Magnetic resonance imaging— Calcaneus.
P
reviously called giant-cell tumor variant by Kolodny in 1927,1 calcifying giant cell tumor by Ewing in 1928,2 and epiphyseal chondromatous giant cell tumor by Codman in 1931,3 Jaffe and Lichtenstein4 introduced the term benign chondroblastoma in 1942 to emphasize that it is distinct from giant-cell tumor. It is an uncommon lesion, accounting for approximately 1% of the benign primary bone tumors.5 Chondroblastoma is a chondrogenetic bone tumor with a predilection for epiphysis, with most cases presenting during the second decade of life. Approximately 7% of chondroblastomas occur in the calca-
From the Department of Orthopaedic Surgery, Nagoya City University Medical School, Nagoya City, Japan. Address correspondence and reprint requests to Takanobu Otsuka, M.D., Department of Orthopaedic Surgery, Nagoya City University Medical School, 1-Kawasumi, Mizuhoku, Nagoya City 467-8601, Japan. © 2002 by the Arthroscopy Association of North America 0749-8063/02/1804-3097$35.00/0 doi:10.1053/jars.2002.31967
430
neus.6 Chondroblastomas occur in a male-to-female ratio of 2:1. On rare occasions, pulmonary implants, or metastases, may occur following surgery.7 Sarcomatous transformation is exceptional. Chondroblastoma is usually regarded and treated as a benign tumor, and cystic varieties of the tumor are rare. Some 10% to 15% of chondroblastoma have an associated aneurysmal bone cyst.8 Although the clinical presentation is highly variable, local, gradually increasing pain, soft-tissue swelling, and tenderness are the most frequent presenting complaints. A clinical diagnosis of chondroblastoma is difficult and confirmation by histologic examination usually is required. Histologically, the tumor is composed of chondroblasts, chondroid, hyaline cartilage, giant cells, and calcification. Radiographically, chondroblastoma is usually radiolucent, although 25% to 60% of lesions show tiny, punctate calcifications; rarely, these may be so extensive as to produce a radiopaque lesion. Most lesions are smaller than 2.5 cm and cause no bone expansion. Although the signal characteristics of chondroblas-
Arthroscopy: The Journal of Arthroscopic and Related Surgery, Vol 18, No 4 (April), 2002: pp 430-435
TREATMENT OF CHONDROBLASTOMA OF THE CALCANEUS
431
was suspected. Dynamic MRI showed strong inclination of the time-intensity curve of the small area within the cystic lesions (Fig 4). We suspected the existence of some primary lesion besides the cysts. Our preoperative diagnosis was a secondary aneurysmal bone cyst. On June 3, 1999, endoscopic curettage without bone grafting combined with biopsy was performed. PROCEDURE
FIGURE 1. Posteroanterior and lateral radiographs of the calcaneus show a large osteolytic lesion.
toma are nonspecific on magnetic resonance imaging (MRI), MRI sometimes shows a fluid-fluid level, bone marrow edema, or soft-tissue edema.9 Chondroblastoma usually is treated by curettage and bone graft. This procedure is curative in approximately 90% of cases. Chondroblastomas with an aneurysmal bone cyst pattern have a dramatically higher recurrence rate than other types, approaching 100%.10 This report presents an unusual case of a chondroblastoma with secondary aneurysmal bone cyst of the calcaneus treated successfully by endoscopic curettage without bone grafting.
Surgery was performed under spinal anesthesia with the patient in the prone position. First, an 18-gauge syringe needle was inserted into the calcaneus. The needle easily punctured the bone, and blood was aspirated. The medial aspect of skin became progressively more depressed as the amount of blood aspirated increased (Fig 5). The cyst was punctured, and this needle was left as a drainage tube. A 1-cm skin incision was made over the posterior aspect of the calcaneus and the arthroscope was inserted through this hole. Red membranous tissue and blood filled the operative field. A 1-cm skin incision was made over the lateral aspect of the calcaneus and again the cyst was punctured. A punch was inserted into the calcaneus through this hole, and the mass, which had strongly enhanced on dynamic MRI, was punched out. The surgical specimen was submitted for frozen section examination. Histologic examination showed large polygonal chondroblasts with mild nuclear pleo-
CASE REPORT In March 1998, a 20-year-old man presented with left heel pain after jumping. He consulted a local physician. As radiography was nondiagnostic, the patient received conservative treatment. In January 1999, the pain increased, and he consulted an outside clinic. Radiography revealed a bone tumor, and he was transferred to our clinic. On initial examination, there was local swelling but little warmth in the area. The patient complained of pain on palpation of the medial aspect of the left heel. The skin over this area was depressed and radiography showed a huge cystic lesion in the left calcaneus with almost complete ablation of the medial cortex on the axial view (Fig 1). Computed tomography (CT) showed thinning and bulging of the cortex (Fig 2). Neither periosteal reaction nor bone formation was observed. Multiple cystic formations were identified on MRI, along with a fluidfluid level and a well-defined lesion with lobulated contours (Fig 3). Stagnation of blood within the cyst
FIGURE 2. A CT study substantiates the presence of the osteolytic area in the calcaneus.
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T. OTSUKA ET AL.
FIGURE 3. MRI shows fluidfluid level.
morphism. Large osteoclast-like giant cells also were present (Fig 6). There were also cystic lesions filled with blood, consistent with an aneurysmal bone cyst. The final diagnosis was reported as chondroblastoma with secondary aneurysmal bone cyst. A sharp curette was inserted from the lateral hole, and the curettage was performed under arthroscopic guidance (Fig 7). Next, a shaver was inserted, and the inner surface of cortex was shaved. The instruments were then exchanged. The arthroscope was inserted through the lateral incision, and punch, sharp curette, shaver were inserted through the posterior incision. Thorough curettage was repeated, and the wound was irrigated with 1,000 mL saline (Fig 8). As the final step of the procedure, straight and angled arthroscopes were inserted to confirm that no tumor remained. No bone was transplanted. Each skin incision was closed with a single stitch, and a bulky dressing was applied. Non–weight-bearing walking was permitted from postoperative day 1. The patella tendon bearing (PTB) orthosis was fixed 2 weeks after operation; the patient was able to walk and he was discharged. Full weight-bearing was permitted after 3 months.
FIGURE 4. Time-intensity curve shows strong inclination of the small area.
There were no complications. A plain radiograph showed the absence of cortex and no cortical bulge. Good bone formation was noted 2 months postoperatively. Remodelling was identified in 4 months (Fig 9). Good bone formation and remodelling progressed uneventfully, and the patient was asymptomatic. There is no evidence of recurrence at 2-year followup. DISCUSSION Huvous and Marcove10 reviewed the published cases of chondroblastoma and reported that the proximal end of the humerus is the single most common location, followed by the proximal end of the femur, the distal end of the femur, and the proximal end of the tibia. The tumor usually originates in a secondary ossification center. Murari11 reviewed 255 cases of primary bone tumors of the foot and reported that the metatarsals are the most common (35.2%) of benign bone tumors, followed by the os calcis (31.4%). Fif-
FIGURE 5. The medial aspect of skin became depressed after aspiration.
TREATMENT OF CHONDROBLASTOMA OF THE CALCANEUS
433
FIGURE 6. This photomicrograph shows chondroblasts and osteoclast-like giant cells. FIGURE 7.
teen of 67 tumors in the os calcis were chondroblastomas. In 1997, Fink12 reported 322 cases of chondroblastoma. Forty-two of these involved the foot, and patients with chondroblastoma of the foot were predominantly male, with a mean age of 25.5 years. This was significantly older than the mean age of patients with chondroblastoma of the long bones (17.3 years). Several other investigators have reviewed chondroblastomas involving the os calcis.13-16 Approximately 7% of chondroblastomas occur in the calcaneus. In the series of 19 calcaneal chondroblastomas reported by Kricun,6 9 were subjacent to the subtalar joint and 5 abutted the posterior facet of the joint. Fink12 noted that chondroblastoma of the foot is most common in the posterior subchondral areas of the talus and calcaneus, as well as in the calcaneal apophysis. Why chondroblastoma occurs mainly in the region of the talocalcaneal articulation and posteriorly in the calcaneus is not certain. Kricun6 suggested that posterior calcaneal tumors might arise from incorporation of cartilagenous rests from the cartilage plate into their
FIGURE 8. Arthroscopic finding before curettage showing reddish membranes (left), shaving (middle), and normal cortex after curettage (right).
Arthroscopic guidance.
apophysis, analogous to epiphyseal chondroblastoma in the long bones. Dahlin5 and Schajowicz17 each reported a 17% incidence of cystic changes in their respective series and termed these lesions cystic chondroblastoma. Jaffe18 postulated that aneurysmal bone cyst may be a secondary phenomenon due to a hemorragic blow-out in a preexisting lesion. Biesecker19 studied 66 cases of aneurysmal bone cyst and found that 32% were associated with some other benign lesion, including 5 chondroblastomas. However cystic chondroblastoma of the calcaneus as occurred in this patient is very rare.6,7,14 The typical radiographic presentation of a chondroblastoma is an eccentrically or centrally located osteolytic lesion that involves an epiphysis or other secondary ossification center. Metaphyseal involvement occurs in 25% to 50% of cases.20 These lesions usually are 1.0 to 3.5 cm and have sharp margins. A sclerotic rim and expansion of affected bone are com-
434
T. OTSUKA ET AL. has several benefits: the incision is small, blood loss is minimal, it is less expensive than open procedures, and both rehabilitation and good visualization can be started sooner because tissue damage is minimal. The blind area was minimized by using a straight arthroscope and an angled arthroscope. Complete curettage was possible through small portals. Endoscopic curettage without bone grafting can be used in cases of a benign bone tumor without soft-part extension. The cavity of the tumor is sufficiently large for endoscopy. Endoscopic curettage without bone grafting is a promising new treatment for chondroblastoma with aneurysmal bone cyst. REFERENCES
FIGURE 9. Radiograph before the endoscopic curettage (upper left), 2 months after surgery (lower left), 6 months after surgery (upper right), and 9 months after surgery (lower right).
mon, and matrix calcification is present in 25% of cases. The lesion may cross an open epiphysis. The signal characteristics of chondroblastoma on MRI are nonspecific, include low to intermediate heterogeneous signal intensity, lobular internal architecture, and fine lobular margins on T2-weighted images. CT and MRI often reveal fluid-fluid level, cortical destruction, cartilagenous invasion, and play an important role in defining the extent of destruction. Radiographic differential diagnoses include giant cell tumor, vascular necrosis, aneurysmal bone cyst, and clear cell chondrosarcoma.21-26 In our case, dynamic MRI showed a small island of increased signal intensity in the multiple fluid-fluid levels. This allowed us to identify the chondroblastoma within the secondary giant aneurysmal bone cyst. Chondroblastoma usually is treated with curettage and bone graft.20 Dahlin5 reported 8 recurrences after curettage among 75 patients and Schajokovicz17 reported 4 recurrences among 29 patients who were treated with curettage. Huvos10 noted that the recurrence rate after curettage was 20% when chondroblastoma was an isolated lesion, but the recurrence rate was 100% when there was an aneurysmal bone cyst component. Two reports of endoscopic treatment of bone tumors have been published. Stricker27 reported a case of chondroblastoma treated by extra-articular endoscopic excision, and Sekiya28 reported 9 cases of enchondromas in the hand treated by endoscopic curettage without bone grafting. Endoscopic curettage
1. Kolodny A. Bone sarcoma. The primary malignant tumors of bone and the giant-cell tumor. Surg Gynecol Obstet 1927;44: suppl 1. 2. Ewing J. Neoplastic diseases. A textbook on tumors. Ed 3. Philadelphia: WB Saunders, 1928:293. 3. Codman EA. Epiphyseal chondromatous giant cell tumors of the upper end of the humerus. Surg Gynecol Obstet 1931;52: 543-548. 4. Jaffe HL, Lichtenstein L. Benign chondroblastoma of bone: A reinterpretation of the so-called calcifying or chondromatous giant cell tumor. Am J Pathol 1942;18:969-991. 5. Dahlin DC, Ivins JC. Benign chondroblastoma. Cancer 1972; 30:401-413. 6. Kricun ME, Kricun R, Haskin ME. Chondroblastoma of the calcaneus: Radiographic features with emphasis on location. AJR Am J Roentgenol 1997;128:613-616. 7. Kyriakos M, Land VJ, Penning HL, Parker SG. Metastatic chondroblastoma. Cancer 1985;55:1770-1789. 8. Mirra JM, Picci P, Gold RH. Bone tumors: Clinical, radiographic correlations. Philadelphia: Lea & Febiger, 1989;589. 9. Weatherall PT, Maale GE, Mendelsohn DB, Sherry CS, Erdman WE, Pascoe HR. Chondroblastoma: Classic and confusing appearance at MR imaging. Radiology 1994;190:467-474. 10. Huvos AG, Marcove RC. Chondroblastoma of bone. Clin Orthop 1973;95:300-311. 11. Murari TM, Callaghan JJ, Berrey BH, Sweet DE. Primary benign and malignant osseous neoplasms of the foot. Foot Ankle 1989;10:68-80. 12. Fink BR, Temple HT, Chiricosta FM, Mizel MS, Murphey MD. Chondroblastoma of the foot. Foot Ankle Int 1997;18: 236-242. 13. Blitch E, Mendicino RW. Chondroblastoma of the calcaneus: Literature review and case presentation. J Foot Surg 1996;35: 250-254. 14. Kahmann R, Gold RH, Eckardt MD, Mirra JM. Case report 337. Skeletal Radiol 1985;14:301-304. 15. Barbera C, Pinotti N, Klein MJ, Lewis MM. An unusual case of cystic chondroblastoma of the calcaneus: A case report. Bull Hosp Joint Dis Orthop Inst 1988;48:88-92. 16. Katz JB, Hunt DW. Chondroblastoma of the calcaneus: A case report. J Am Podiatry Assoc 1975;65:184-187. 17. Schajowicz F, Gallardo H. Epiphysial chondroblastoma of bone. J Bone Joint Surg Br 1970;52:205-226. 18. Jaffe HL. Aneurysmal bone cyst. Bull Hosp Joint Dis 1950; 11:3-13. 19. Biesecker JL, Marcove RL, Huvos AG, Mike V. Aneurysmal
TREATMENT OF CHONDROBLASTOMA OF THE CALCANEUS
20. 21. 22. 23.
bone cysts. A clinicopathologic study of 66 cases. Cancer 1970;26:615-625. Ramappa AJ, Lee FYI, Tang P, Carlson JR, Gebhardt MC, Mankin HJ. Chondroblastoma of bone. J Bone Joint Surg Am 2000;82:1140-1145. Bloem JL, Mulder JD. Chondroblastoma: A clinical and radiological study of 104 cases. Skeletal Radiol 1985;14:1-9. Garces PB, Melamed JW, Matinez S, Bentley RC. Aneurysmal bone cyst formation within a chondroblastoma: Case report. Can Assoc Radiol J 1997;48:25-27. Sundaram M, McGuire MH, Naunheim K, Schajowicz F. Case report 467. Skeletal Radiol 1988;17:136-140.
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24. Lijoi F. Observations on a case of cystic epiphyseal chondroblastoma. Ital J Orthop Traumatol 1982;8:207-209. 25. Crim JR, Gold RH, Mirra JM, Eckardt M. Case report 748. Skeletal Radiol 1992;21:403-405. 26. Lewis MM, Bullough PG. An unusual case of cystic chondroblastoma of the patella. Clin Orthop 1976;121:188-190. 27. Stricker SJ. Extraarticular endoscopic excision of femoral head chondroblastoma. J Pediatr Orthop 1995;15:578-581. 28. Sekiya I, Matsui N, Otsuka T, Kobayashi M, Tsuchiya D. The treatment of enchondroblastomas in the hand by endoscopic curettage without bone grafting. J Hand Surg [Br] 1997;22: 230-234.
Treatment of Chondroblastoma of the Calcaneus With a Secondary Aneurysmal Bone Cyst Using Endoscopic Curettage Without Bone Grafting Takanobu Otsuka, M.D., Masaaki Kobayashi, M.D., Masato Yonezawa, M.D., Fumiaki Kamiyama, M.D., Yasusi Matsushita, M.D., and Nobuo Matsui, M.D.
Abstract: Chondroblastoma is a relatively rare benign bone tumor. Approximately 7% of chondroblastomas occur in the calcaneus, and 17% of chondroblastoma associated with cystic lesions. We report a case of a chondroblastoma in the calcaneus with a secondary aneurysmal bone cyst treated successfully by endoscopic curettage without bone grafting. New bone formation is facilitated by minimal damage to the bone and soft tissue. The cosmetic results of this procedure are good. Two years later, the patient is asymptomatic with no radiographic evidence of recurrence. Endoscopic curettage without bone grafting is a promising new treatment for chondroblastoma. Key Words: Chondroblastoma—Aneurysmal bone cyst—Endoscopic curettage—Magnetic resonance imaging— Calcaneus.
P
reviously called giant-cell tumor variant by Kolodny in 1927,1 calcifying giant cell tumor by Ewing in 1928,2 and epiphyseal chondromatous giant cell tumor by Codman in 1931,3 Jaffe and Lichtenstein4 introduced the term benign chondroblastoma in 1942 to emphasize that it is distinct from giant-cell tumor. It is an uncommon lesion, accounting for approximately 1% of the benign primary bone tumors.5 Chondroblastoma is a chondrogenetic bone tumor with a predilection for epiphysis, with most cases presenting during the second decade of life. Approximately 7% of chondroblastomas occur in the calca-
From the Department of Orthopaedic Surgery, Nagoya City University Medical School, Nagoya City, Japan. Address correspondence and reprint requests to Takanobu Otsuka, M.D., Department of Orthopaedic Surgery, Nagoya City University Medical School, 1-Kawasumi, Mizuhoku, Nagoya City 467-8601, Japan. © 2002 by the Arthroscopy Association of North America 0749-8063/02/1804-3097$35.00/0 doi:10.1053/jars.2002.31967
430
neus.6 Chondroblastomas occur in a male-to-female ratio of 2:1. On rare occasions, pulmonary implants, or metastases, may occur following surgery.7 Sarcomatous transformation is exceptional. Chondroblastoma is usually regarded and treated as a benign tumor, and cystic varieties of the tumor are rare. Some 10% to 15% of chondroblastoma have an associated aneurysmal bone cyst.8 Although the clinical presentation is highly variable, local, gradually increasing pain, soft-tissue swelling, and tenderness are the most frequent presenting complaints. A clinical diagnosis of chondroblastoma is difficult and confirmation by histologic examination usually is required. Histologically, the tumor is composed of chondroblasts, chondroid, hyaline cartilage, giant cells, and calcification. Radiographically, chondroblastoma is usually radiolucent, although 25% to 60% of lesions show tiny, punctate calcifications; rarely, these may be so extensive as to produce a radiopaque lesion. Most lesions are smaller than 2.5 cm and cause no bone expansion. Although the signal characteristics of chondroblas-
Arthroscopy: The Journal of Arthroscopic and Related Surgery, Vol 18, No 4 (April), 2002: pp 430-435
TREATMENT OF CHONDROBLASTOMA OF THE CALCANEUS
431
was suspected. Dynamic MRI showed strong inclination of the time-intensity curve of the small area within the cystic lesions (Fig 4). We suspected the existence of some primary lesion besides the cysts. Our preoperative diagnosis was a secondary aneurysmal bone cyst. On June 3, 1999, endoscopic curettage without bone grafting combined with biopsy was performed. PROCEDURE
FIGURE 1. Posteroanterior and lateral radiographs of the calcaneus show a large osteolytic lesion.
toma are nonspecific on magnetic resonance imaging (MRI), MRI sometimes shows a fluid-fluid level, bone marrow edema, or soft-tissue edema.9 Chondroblastoma usually is treated by curettage and bone graft. This procedure is curative in approximately 90% of cases. Chondroblastomas with an aneurysmal bone cyst pattern have a dramatically higher recurrence rate than other types, approaching 100%.10 This report presents an unusual case of a chondroblastoma with secondary aneurysmal bone cyst of the calcaneus treated successfully by endoscopic curettage without bone grafting.
Surgery was performed under spinal anesthesia with the patient in the prone position. First, an 18-gauge syringe needle was inserted into the calcaneus. The needle easily punctured the bone, and blood was aspirated. The medial aspect of skin became progressively more depressed as the amount of blood aspirated increased (Fig 5). The cyst was punctured, and this needle was left as a drainage tube. A 1-cm skin incision was made over the posterior aspect of the calcaneus and the arthroscope was inserted through this hole. Red membranous tissue and blood filled the operative field. A 1-cm skin incision was made over the lateral aspect of the calcaneus and again the cyst was punctured. A punch was inserted into the calcaneus through this hole, and the mass, which had strongly enhanced on dynamic MRI, was punched out. The surgical specimen was submitted for frozen section examination. Histologic examination showed large polygonal chondroblasts with mild nuclear pleo-
CASE REPORT In March 1998, a 20-year-old man presented with left heel pain after jumping. He consulted a local physician. As radiography was nondiagnostic, the patient received conservative treatment. In January 1999, the pain increased, and he consulted an outside clinic. Radiography revealed a bone tumor, and he was transferred to our clinic. On initial examination, there was local swelling but little warmth in the area. The patient complained of pain on palpation of the medial aspect of the left heel. The skin over this area was depressed and radiography showed a huge cystic lesion in the left calcaneus with almost complete ablation of the medial cortex on the axial view (Fig 1). Computed tomography (CT) showed thinning and bulging of the cortex (Fig 2). Neither periosteal reaction nor bone formation was observed. Multiple cystic formations were identified on MRI, along with a fluidfluid level and a well-defined lesion with lobulated contours (Fig 3). Stagnation of blood within the cyst
FIGURE 2. A CT study substantiates the presence of the osteolytic area in the calcaneus.
432
T. OTSUKA ET AL.
FIGURE 3. MRI shows fluidfluid level.
morphism. Large osteoclast-like giant cells also were present (Fig 6). There were also cystic lesions filled with blood, consistent with an aneurysmal bone cyst. The final diagnosis was reported as chondroblastoma with secondary aneurysmal bone cyst. A sharp curette was inserted from the lateral hole, and the curettage was performed under arthroscopic guidance (Fig 7). Next, a shaver was inserted, and the inner surface of cortex was shaved. The instruments were then exchanged. The arthroscope was inserted through the lateral incision, and punch, sharp curette, shaver were inserted through the posterior incision. Thorough curettage was repeated, and the wound was irrigated with 1,000 mL saline (Fig 8). As the final step of the procedure, straight and angled arthroscopes were inserted to confirm that no tumor remained. No bone was transplanted. Each skin incision was closed with a single stitch, and a bulky dressing was applied. Non–weight-bearing walking was permitted from postoperative day 1. The patella tendon bearing (PTB) orthosis was fixed 2 weeks after operation; the patient was able to walk and he was discharged. Full weight-bearing was permitted after 3 months.
FIGURE 4. Time-intensity curve shows strong inclination of the small area.
There were no complications. A plain radiograph showed the absence of cortex and no cortical bulge. Good bone formation was noted 2 months postoperatively. Remodelling was identified in 4 months (Fig 9). Good bone formation and remodelling progressed uneventfully, and the patient was asymptomatic. There is no evidence of recurrence at 2-year followup. DISCUSSION Huvous and Marcove10 reviewed the published cases of chondroblastoma and reported that the proximal end of the humerus is the single most common location, followed by the proximal end of the femur, the distal end of the femur, and the proximal end of the tibia. The tumor usually originates in a secondary ossification center. Murari11 reviewed 255 cases of primary bone tumors of the foot and reported that the metatarsals are the most common (35.2%) of benign bone tumors, followed by the os calcis (31.4%). Fif-
FIGURE 5. The medial aspect of skin became depressed after aspiration.
TREATMENT OF CHONDROBLASTOMA OF THE CALCANEUS
433
FIGURE 6. This photomicrograph shows chondroblasts and osteoclast-like giant cells. FIGURE 7.
teen of 67 tumors in the os calcis were chondroblastomas. In 1997, Fink12 reported 322 cases of chondroblastoma. Forty-two of these involved the foot, and patients with chondroblastoma of the foot were predominantly male, with a mean age of 25.5 years. This was significantly older than the mean age of patients with chondroblastoma of the long bones (17.3 years). Several other investigators have reviewed chondroblastomas involving the os calcis.13-16 Approximately 7% of chondroblastomas occur in the calcaneus. In the series of 19 calcaneal chondroblastomas reported by Kricun,6 9 were subjacent to the subtalar joint and 5 abutted the posterior facet of the joint. Fink12 noted that chondroblastoma of the foot is most common in the posterior subchondral areas of the talus and calcaneus, as well as in the calcaneal apophysis. Why chondroblastoma occurs mainly in the region of the talocalcaneal articulation and posteriorly in the calcaneus is not certain. Kricun6 suggested that posterior calcaneal tumors might arise from incorporation of cartilagenous rests from the cartilage plate into their
FIGURE 8. Arthroscopic finding before curettage showing reddish membranes (left), shaving (middle), and normal cortex after curettage (right).
Arthroscopic guidance.
apophysis, analogous to epiphyseal chondroblastoma in the long bones. Dahlin5 and Schajowicz17 each reported a 17% incidence of cystic changes in their respective series and termed these lesions cystic chondroblastoma. Jaffe18 postulated that aneurysmal bone cyst may be a secondary phenomenon due to a hemorragic blow-out in a preexisting lesion. Biesecker19 studied 66 cases of aneurysmal bone cyst and found that 32% were associated with some other benign lesion, including 5 chondroblastomas. However cystic chondroblastoma of the calcaneus as occurred in this patient is very rare.6,7,14 The typical radiographic presentation of a chondroblastoma is an eccentrically or centrally located osteolytic lesion that involves an epiphysis or other secondary ossification center. Metaphyseal involvement occurs in 25% to 50% of cases.20 These lesions usually are 1.0 to 3.5 cm and have sharp margins. A sclerotic rim and expansion of affected bone are com-
434
T. OTSUKA ET AL. has several benefits: the incision is small, blood loss is minimal, it is less expensive than open procedures, and both rehabilitation and good visualization can be started sooner because tissue damage is minimal. The blind area was minimized by using a straight arthroscope and an angled arthroscope. Complete curettage was possible through small portals. Endoscopic curettage without bone grafting can be used in cases of a benign bone tumor without soft-part extension. The cavity of the tumor is sufficiently large for endoscopy. Endoscopic curettage without bone grafting is a promising new treatment for chondroblastoma with aneurysmal bone cyst. REFERENCES
FIGURE 9. Radiograph before the endoscopic curettage (upper left), 2 months after surgery (lower left), 6 months after surgery (upper right), and 9 months after surgery (lower right).
mon, and matrix calcification is present in 25% of cases. The lesion may cross an open epiphysis. The signal characteristics of chondroblastoma on MRI are nonspecific, include low to intermediate heterogeneous signal intensity, lobular internal architecture, and fine lobular margins on T2-weighted images. CT and MRI often reveal fluid-fluid level, cortical destruction, cartilagenous invasion, and play an important role in defining the extent of destruction. Radiographic differential diagnoses include giant cell tumor, vascular necrosis, aneurysmal bone cyst, and clear cell chondrosarcoma.21-26 In our case, dynamic MRI showed a small island of increased signal intensity in the multiple fluid-fluid levels. This allowed us to identify the chondroblastoma within the secondary giant aneurysmal bone cyst. Chondroblastoma usually is treated with curettage and bone graft.20 Dahlin5 reported 8 recurrences after curettage among 75 patients and Schajokovicz17 reported 4 recurrences among 29 patients who were treated with curettage. Huvos10 noted that the recurrence rate after curettage was 20% when chondroblastoma was an isolated lesion, but the recurrence rate was 100% when there was an aneurysmal bone cyst component. Two reports of endoscopic treatment of bone tumors have been published. Stricker27 reported a case of chondroblastoma treated by extra-articular endoscopic excision, and Sekiya28 reported 9 cases of enchondromas in the hand treated by endoscopic curettage without bone grafting. Endoscopic curettage
1. Kolodny A. Bone sarcoma. The primary malignant tumors of bone and the giant-cell tumor. Surg Gynecol Obstet 1927;44: suppl 1. 2. Ewing J. Neoplastic diseases. A textbook on tumors. Ed 3. Philadelphia: WB Saunders, 1928:293. 3. Codman EA. Epiphyseal chondromatous giant cell tumors of the upper end of the humerus. Surg Gynecol Obstet 1931;52: 543-548. 4. Jaffe HL, Lichtenstein L. Benign chondroblastoma of bone: A reinterpretation of the so-called calcifying or chondromatous giant cell tumor. Am J Pathol 1942;18:969-991. 5. Dahlin DC, Ivins JC. Benign chondroblastoma. Cancer 1972; 30:401-413. 6. Kricun ME, Kricun R, Haskin ME. Chondroblastoma of the calcaneus: Radiographic features with emphasis on location. AJR Am J Roentgenol 1997;128:613-616. 7. Kyriakos M, Land VJ, Penning HL, Parker SG. Metastatic chondroblastoma. Cancer 1985;55:1770-1789. 8. Mirra JM, Picci P, Gold RH. Bone tumors: Clinical, radiographic correlations. Philadelphia: Lea & Febiger, 1989;589. 9. Weatherall PT, Maale GE, Mendelsohn DB, Sherry CS, Erdman WE, Pascoe HR. Chondroblastoma: Classic and confusing appearance at MR imaging. Radiology 1994;190:467-474. 10. Huvos AG, Marcove RC. Chondroblastoma of bone. Clin Orthop 1973;95:300-311. 11. Murari TM, Callaghan JJ, Berrey BH, Sweet DE. Primary benign and malignant osseous neoplasms of the foot. Foot Ankle 1989;10:68-80. 12. Fink BR, Temple HT, Chiricosta FM, Mizel MS, Murphey MD. Chondroblastoma of the foot. Foot Ankle Int 1997;18: 236-242. 13. Blitch E, Mendicino RW. Chondroblastoma of the calcaneus: Literature review and case presentation. J Foot Surg 1996;35: 250-254. 14. Kahmann R, Gold RH, Eckardt MD, Mirra JM. Case report 337. Skeletal Radiol 1985;14:301-304. 15. Barbera C, Pinotti N, Klein MJ, Lewis MM. An unusual case of cystic chondroblastoma of the calcaneus: A case report. Bull Hosp Joint Dis Orthop Inst 1988;48:88-92. 16. Katz JB, Hunt DW. Chondroblastoma of the calcaneus: A case report. J Am Podiatry Assoc 1975;65:184-187. 17. Schajowicz F, Gallardo H. Epiphysial chondroblastoma of bone. J Bone Joint Surg Br 1970;52:205-226. 18. Jaffe HL. Aneurysmal bone cyst. Bull Hosp Joint Dis 1950; 11:3-13. 19. Biesecker JL, Marcove RL, Huvos AG, Mike V. Aneurysmal
TREATMENT OF CHONDROBLASTOMA OF THE CALCANEUS
20. 21. 22. 23.
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