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Enchondroma protuberans: A case report
Enchondroma Protuberans: A Case Report Alexander Bee Dagum, MD, Toronto, Canada, Steven P. Sampson, MD, Stony Brook, NY Enchondroma protuberans is a rare benign cartilaginous tumor. There have been only 5 cases previously described in the world literature. It must be differentiated from other more common and aggressive tumors to avoid radical resection. A case report of a 7-year-old boy presenting with enchondroma protuberans in the third metacarpal is presented. The patient underwent an initial incisional biopsy followed by a marginal resection of the soft tissue component and intramedullary curettage. After a 36-month follow-up period, there is no evidence of recurrence. (I Hand Surg 1998;23A:338-341. Copyright 9 1998 by the American Society for Surgery of the Hand.)
Enchondroma protuberans is a rare benign chondromatous tumor arising in the medullary space and growing beyond the cortex.~ 4 There has been no previously reported case of enchondroma protuberans occurring in the hand. To treat enchondroma protuberans appropriately and to avoid recurrence and unnecessary radical resection, it is important to differentiate it from chondrosarcoma, periosteal chondroma, and osteochondroma.
Case Report A 7-year-old right-handed boy was referred in October 1994 with a 2-month history of a painless left dorsal hand swelling. There was no history of injury or systemic s y m p t o m a t o l o g y . Examination revealed a 2 • 3 cm firm mass deep over the mid
From the Department of Surgery, Division of Plastic Surgery, University of Toronto,Toronto,Canada; and the Department of Orthopaedic Surgery, Division of Hand and Microsurgery, State University of New York, Stony Brook. Received for publication June 25, 1997; accepted in revised form January 16, 1998. No benefits in any tbrm have been receivedor will be receivedfrom a commercial party related directly or indirectly to the subject of this article. Reprint requests: Alexander Bee Dagum, MD, 117 King St E, Oshawa, Ontario, Canada LIH 1B9. Copyright9 1998by the AmericanSocietyfor Surgeryof the Hand. 0363-5023/98/23A02-002553.00/0 338
The Journal of Hand Surgery
to distal dorsal portion of the third metacarpal and second web space. The overlying skin and extensor tendons were unaffected. The remainder of the hand examination was normal. There was no palpable l y m p h a d e n o p a t h y and the general physical examination was normal. A routine hand x-ray film from the referring institution revealed a speckled calcific osteolytic lesion within the midshaft of the third metacarpal measuring 2 cm with radial cortical breakthrough (Fig. 1A). The contiguous soft tissue mass had caused thinning o f the ulnar surface of the second metacarpal. Magnetic resonance imaging demonstrated a 2-cm ovoid lesion within the medullary cavity of the midshaft of the third metacarpal with cortical breakthrough and a 2 • 2 cm contiguous soft tissue mass extending into the dorsal interosseous muscle of the second web (Fig. 2). The results of laboratory studies, chest x-ray film, and bone scan indicated
Figure 1. (A) A preoperative radiograph showing an osteolytic lesion of the third metacarpal. (B) An intraoperarive postsurgical resection radiograph shows the extent of surgical excision. (C) At 8 weeks after surgery, an extensive callus is noted. (D) At the 2-year follow-up visit, there is no evidence of recurrence and the third metacarpal has filled with mature bone.
The Journal of Hand Surgery / Vol. 23A No. 2 March 1998
A
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340 Dagumand Sampson / Enchondroma Protuberans
Figure 2. Magnetic resonance imaging of the tumor demonstrates a 2-cm ovoid lesion within the medullary canal with cortical breakthrough and a 2-cm contiguous mass extending into the dorsal interosseous muscle.
no evidence of metastatic disease. Incisional biopsy of the soft tissue mass revealed a benign cartilaginous tumor. The patient then had en b l o c marginal resection of the bone and soft tissue components of the tumor (i.e., with a small cuff of clinically normal interosseous muscle and metacarpal). The ulnar shaft of the metacarpal was left intact, and the medullary canal was curetted and burred with a power drill. After surgery, the patient had weakness of the partially resected interossei muscles, which recovered over 6 months. The medullary canal filled with new bone over the next year (Fig. I B, C, D). The final clinical pathologic diagnosis was that of enchondroma protuberans; at the 36-month follow-up examination there was no evidence of local recurrence.
Discussion There have been only 5 previous cases of enchondroma protuberans described in the literature: 3 were in the humerus and 2 were in the ribs.~-4 Enchondroma protuberans is a benign chondromatous tumor that arises in the medullary canal and grows through
the bony cortex, forming a prominent exophytic mass in the surrounding soft tissue. Enchondroma protuberance should be considered in the differential diagnosis of a hand tumor whenever these features are noted. The findings on plain x-ray films could suggest a periosteal chondroma even though the lesion is centered in the diaphysis rather than the metaphysis. However, the magnetic resonance imaging delineated extensive contiguous medullary involvement, which does not occur with a periosteal chondroma. 5 The absence of a cartilage cap and underlying trabecular bone ruled out osteochondroma before the incisional biopsy, Concurrent osteochondroma and enchondroma has been previously reported; however, this is characterized by noncontiguous spread. Enchondroma protuberans has been mistaken for chondrosarcoma, particularly in the ribs, where malignant primary bone tumors are more common. 2'4 Chondrosarcomas are rare in the hand, particularly in children. However, overall, they are the most common primary malignant bone tumor of the hand. 5 The radiologic work-up suggested an aggressive le-
The Journal of H a n d Surgery / Vol. 23A No. 2 M a r c h 1998
sion with cortical destruction and an adjacent soft tissue mass. Because of the clinical presentation and radiologic picture in such cases, typical incisional biopsy before definitive resection should be performed. Marginal resection of the soft tissue protuberance and cortical bone with curettage (intralesional excision) of the intramedullary component was curative in the 3 cases described in long bones,l"3 and no local recurrence has been seen in this case after 36 months. The authors thank Dr Margaret Nuovo, Department of Pathology, Stony Brook University Hospital, and Dr Howard D. Dorfman, Department of Pathology, Albert Einstein College of Medicine, for their invaluable assistance in the pathologic diagnosis.
341
References 1. Caballes RL. Enchondroma protuberans masquerading as osteochondroma. Hum Pathol 1982;13:734-739. 2. Keating RB, Wright PW, Staple TW. Enchondroma protuberans of the rib. Skeletal Radiol 1985;13:55 58. 3. Crim JR, Mirra JM. Enchondroma protuberans: report ol' a case and its distinction from chondrosarcoma and osteochondroma adjacent to an enchondroma. Skeletal Radiol 1990; 19:431-434. 4. Isogami K, Suda H, Ohta T, Matsura H, Sakuma H. A case of enchondroma protuberans with destroying the rib bone. Kyobu Geka 1992;45:907-909. 5. Feldman F. Primary bone tumors of the hand and carpus. Hand Clin 1987;3:269-289.
Enchondroma protuberans is a rare benign chondromatous tumor arising in the medullary space and growing beyond the cortex.~ 4 There has been no previously reported case of enchondroma protuberans occurring in the hand. To treat enchondroma protuberans appropriately and to avoid recurrence and unnecessary radical resection, it is important to differentiate it from chondrosarcoma, periosteal chondroma, and osteochondroma.
Case Report A 7-year-old right-handed boy was referred in October 1994 with a 2-month history of a painless left dorsal hand swelling. There was no history of injury or systemic s y m p t o m a t o l o g y . Examination revealed a 2 • 3 cm firm mass deep over the mid
From the Department of Surgery, Division of Plastic Surgery, University of Toronto,Toronto,Canada; and the Department of Orthopaedic Surgery, Division of Hand and Microsurgery, State University of New York, Stony Brook. Received for publication June 25, 1997; accepted in revised form January 16, 1998. No benefits in any tbrm have been receivedor will be receivedfrom a commercial party related directly or indirectly to the subject of this article. Reprint requests: Alexander Bee Dagum, MD, 117 King St E, Oshawa, Ontario, Canada LIH 1B9. Copyright9 1998by the AmericanSocietyfor Surgeryof the Hand. 0363-5023/98/23A02-002553.00/0 338
The Journal of Hand Surgery
to distal dorsal portion of the third metacarpal and second web space. The overlying skin and extensor tendons were unaffected. The remainder of the hand examination was normal. There was no palpable l y m p h a d e n o p a t h y and the general physical examination was normal. A routine hand x-ray film from the referring institution revealed a speckled calcific osteolytic lesion within the midshaft of the third metacarpal measuring 2 cm with radial cortical breakthrough (Fig. 1A). The contiguous soft tissue mass had caused thinning o f the ulnar surface of the second metacarpal. Magnetic resonance imaging demonstrated a 2-cm ovoid lesion within the medullary cavity of the midshaft of the third metacarpal with cortical breakthrough and a 2 • 2 cm contiguous soft tissue mass extending into the dorsal interosseous muscle of the second web (Fig. 2). The results of laboratory studies, chest x-ray film, and bone scan indicated
Figure 1. (A) A preoperative radiograph showing an osteolytic lesion of the third metacarpal. (B) An intraoperarive postsurgical resection radiograph shows the extent of surgical excision. (C) At 8 weeks after surgery, an extensive callus is noted. (D) At the 2-year follow-up visit, there is no evidence of recurrence and the third metacarpal has filled with mature bone.
The Journal of Hand Surgery / Vol. 23A No. 2 March 1998
A
339
340 Dagumand Sampson / Enchondroma Protuberans
Figure 2. Magnetic resonance imaging of the tumor demonstrates a 2-cm ovoid lesion within the medullary canal with cortical breakthrough and a 2-cm contiguous mass extending into the dorsal interosseous muscle.
no evidence of metastatic disease. Incisional biopsy of the soft tissue mass revealed a benign cartilaginous tumor. The patient then had en b l o c marginal resection of the bone and soft tissue components of the tumor (i.e., with a small cuff of clinically normal interosseous muscle and metacarpal). The ulnar shaft of the metacarpal was left intact, and the medullary canal was curetted and burred with a power drill. After surgery, the patient had weakness of the partially resected interossei muscles, which recovered over 6 months. The medullary canal filled with new bone over the next year (Fig. I B, C, D). The final clinical pathologic diagnosis was that of enchondroma protuberans; at the 36-month follow-up examination there was no evidence of local recurrence.
Discussion There have been only 5 previous cases of enchondroma protuberans described in the literature: 3 were in the humerus and 2 were in the ribs.~-4 Enchondroma protuberans is a benign chondromatous tumor that arises in the medullary canal and grows through
the bony cortex, forming a prominent exophytic mass in the surrounding soft tissue. Enchondroma protuberance should be considered in the differential diagnosis of a hand tumor whenever these features are noted. The findings on plain x-ray films could suggest a periosteal chondroma even though the lesion is centered in the diaphysis rather than the metaphysis. However, the magnetic resonance imaging delineated extensive contiguous medullary involvement, which does not occur with a periosteal chondroma. 5 The absence of a cartilage cap and underlying trabecular bone ruled out osteochondroma before the incisional biopsy, Concurrent osteochondroma and enchondroma has been previously reported; however, this is characterized by noncontiguous spread. Enchondroma protuberans has been mistaken for chondrosarcoma, particularly in the ribs, where malignant primary bone tumors are more common. 2'4 Chondrosarcomas are rare in the hand, particularly in children. However, overall, they are the most common primary malignant bone tumor of the hand. 5 The radiologic work-up suggested an aggressive le-
The Journal of H a n d Surgery / Vol. 23A No. 2 M a r c h 1998
sion with cortical destruction and an adjacent soft tissue mass. Because of the clinical presentation and radiologic picture in such cases, typical incisional biopsy before definitive resection should be performed. Marginal resection of the soft tissue protuberance and cortical bone with curettage (intralesional excision) of the intramedullary component was curative in the 3 cases described in long bones,l"3 and no local recurrence has been seen in this case after 36 months. The authors thank Dr Margaret Nuovo, Department of Pathology, Stony Brook University Hospital, and Dr Howard D. Dorfman, Department of Pathology, Albert Einstein College of Medicine, for their invaluable assistance in the pathologic diagnosis.
341
References 1. Caballes RL. Enchondroma protuberans masquerading as osteochondroma. Hum Pathol 1982;13:734-739. 2. Keating RB, Wright PW, Staple TW. Enchondroma protuberans of the rib. Skeletal Radiol 1985;13:55 58. 3. Crim JR, Mirra JM. Enchondroma protuberans: report ol' a case and its distinction from chondrosarcoma and osteochondroma adjacent to an enchondroma. Skeletal Radiol 1990; 19:431-434. 4. Isogami K, Suda H, Ohta T, Matsura H, Sakuma H. A case of enchondroma protuberans with destroying the rib bone. Kyobu Geka 1992;45:907-909. 5. Feldman F. Primary bone tumors of the hand and carpus. Hand Clin 1987;3:269-289.