Venous secondary to first rib osteochondroma in a pediatric patient

P. Joshua O’Brien, MD,a Shalini Ramasunder, MD,b and Mitchell W. Cox, MD,a Durham, NC

Osteochondromas account for 30% to 50% of benign osseous tumors and 10% of all bone tumors. Most of these lesions are found incidentally on imaging studies obtained for other reasons. Vascular compromise due to osteochondroma is a rare but well-recognized phenomenon and typically occurs in the lower extremity as a result of a tumor mass projecting into the popliteal fossa. We present the very rare case of a pediatric patient with venous thoracic outlet syndrome due to an osteochondroma of the first rib, and to our knowledge, this report is only the second such occurrence in the medical literature. (J Vasc Surg 2011;53:811-3.)

Subclavian thrombosis at the level of the thoracic guidewire could be navigated around a firm, fixed mass with a outlet due to mechanical compression is a well-described rounded contour that seemed most consistent with compression phenomenon referred to colloquially as Paget-Schroetter due to the underlying bony mass lesion. From this appearance, we syndrome, effort thrombosis, or venous thoracic outlet determined that the volume of acute thrombus was not significant syndrome. The most common cause is likely a dynamic enough to require thrombolysis and elected to forego the usual compression of the vein by normal-appearing bony and lytic therapy. ligamentous structures as it exits the thorax between the The following day, she underwent first rib resection through first rib and clavicle. This chronic compression may be supraclavicular and infraclavicular incisions without incident. A exacerbated by vigorous physical training, and typically broad-based osteochondroma of the first rib was noted to be presents as an upper extremity in an compressing the subclavian vein and was resected with wide mar- otherwise healthy young adult. In unusual circumstances, gins (Fig 2). A small pleural defect was repaired primarily and did however, bony anomalies of the ribs or the clavicle may not require chest tube placement. We did not perform intraoper- exist, causing a subclavian vein occlusion in patients outside ative or venolysis, but planned for a later venogram the normal age range for venous thoracic outlet syndrome. with possible of any residual stenosis; however, tense Herein, we describe such a case. arm edema redeveloped 12 hours postoperatively. An immediate venogram demonstrated acute thrombosis of CASE REPORT the subclavian vein, and we performed mechanical thrombectomy A 12-year-old girl presented to a local emergency department with the Angiojet (Medrad Interventional, Warrendale, Pa) device, with sudden onset of tense edema of the right arm. The patient and followed by angioplasty of a residual subclavian vein stenosis her parents reported no history of trauma to the arm or shoulder, (Fig 3). Anticoagulation was begun with heparin after the proce- no family history of hypercoagulability, and no prior symptoms of dure and her arm edema decreased significantly. Despite therapeu- pain or swelling in the extremity. The initial venous duplex imag- tic anticoagulation, there were no bleeding complications in the ing was consistent with axillosubclavian deep vein thrombosis, and surgical field or at the site of . She was discharged enoxaparin therapy was begun. A further evaluation included a home 4 days postoperatively with enoxaparin therapy. Pathology chest radiograph, which was unremarkable, and a computed to- returned as benign osteochondroma. mography scan of the chest, which showed a bony mass of the first She was re-evaluated at 1 month, and the arm edema had rib consistent with osteochondroma. completely resolved. Venous duplex imaging showed patent axil- The patient was transferred to our facility 3 days after her lary and subclavian with normal flow characteristics and no initial presentation. She reported some improvement in the evidence of residual thrombus. After a discussion with the pediatric amount of swelling; however, the right arm was still significantly hematology service, the patient’s parents chose to continue with enlarged. A venogram demonstrated a filling defect in the subcla- enoxaparin rather than switch to warfarin, and anticoagulation was vian vein at the level of the first rib (Fig 1). With some difficulty, a continued for 3 months. A duplex study at 6 months demonstrated patent axillary and subclavian veins with some chronic residual From the Section of Vascular , Department of Surgery,a and the thrombus. Department of Orthopaedic Surgery,b Duke University Medical Center. Competition of interest: none. DISCUSSION Reprint requests: Mitchell W. Cox, MD, Department of Surgery, Section of , Duke University Medical Center 2833, Durham, NC, Osteochondromas are the most common of the benign 27710 (e-mail: [email protected]). bone tumors and are usually present between the first and The editors and reviewers of this article have no relevant financial relationships third decades of life, with a predilection for males.1 Al- to disclose per the JVS policy that requires reviewers to decline review of any though the exact etiology of osteochondromas is un- manuscript for which they may have a competition of interest. known, they are thought to be caused by a portion of the 0741-5214/$36.00 Copyright © 2011 by the Society for Vascular Surgery. physis herniating through the peripheral growth plate sec- doi:10.1016/j.jvs.2010.09.067 ondary to a deficiency in the perichondrial ring.2 Evidence 811 JOURNAL OF VASCULAR SURGERY 812 O’Brien et al March 2011

of these lesions are found incidentally on imaging studies obtained for other reasons. The most common clinical presentation is that of a painless mass. On occasion, how- ever, these lesions cause pain secondary to impingement on surrounding neurovascular or musculotendinous struc- tures, pathologic fracture through the stalk of a peduncu- lated lesion, or formation of an inflamed bursal sac over the lesion. These tumors occur most commonly about the knee, followed by the proximal humerus and the pelvis. Osteochondromas typically cease growing once a pa- tient reaches skeletal maturity and can be classified accord- ing to the rapidity of their growth. The salient features of this lesion include continuity of both the medullary canal and the cortex from the underlying bone into the lesion as Fig 1. Venogram demonstrates the fixed defect in the subclavian well as a cartilage cap that measures Ͻ2 cm. As one ap- vein at the level of the first rib. proaches skeletal maturity, the cartilage cap typically ossi- fies. Approximately 1% of solitary lesions undergo malig- nant transformation to low-grade osteosarcoma or chondrosarcoma, generally signaled by new-onset pain or continued growth after skeletal maturity.3 Most osteochondromas can be evaluated on radio- graphs. However, when the lesion presents on a flat bone such as the scapula, ilium, or the ribs, a CT scan can be helpful to better localize the lesion. Magnetic reso- nance imaging can help to delineate the exact extent of the cartilage cap, which may not be clearly visualized on radiographs or CT and therefore can be useful in evalu- ating the relationship of the tumor to the surrounding vital structures.4 Except in the case of severe pain or neurovascular compromise, most of these lesions do not require surgical treatment. If resection is required, it is imperative to re- move the entire cartilage cap en bloc with the surrounding perichondrium to limit the chance of recurrence (2%).5,6 Vascular compromise due to osteochondroma is a rare but well-recognized phenomenon that typically occurs in the lower extremity as a result of a tumor mass projecting Fig 2. First rib specimen with osteochondroma. into the popliteal fossa. Most contemporary reports of osteochondroma involving the chest wall, particularly the ribs, describe hemothorax of unclear etiology. There are also several reports of osteochondroma involving the lateral clavicle presenting with symptoms of pain or neurologic deficit. Two previous reports describe subclavian vein thrombosis (Paget-Schroetter syndrome) as a result of compression secondary to a medial congenital tumor of the clavicle, which were successfully treated with partial resec- tion of the clavicle.7,8 The only other case of venous tho- racic outlet syndrome due to osteochondroma of the first rib was published in 1963,9 and to our knowledge, this report is only the second such occurrence. Although the most appropriate surgical technique for Fig 3. Postoperative venogram after mechanical thrombectomy. first rib resection is frequently discussed and debated, tho- racic outlet decompression is usually recommended for patients with axillosubclavian deep vein thrombosis due to to support this theory comes from the observation that compression at the costoclavicular junction. The goal, when seen within the first decade of life, osteochondromas which can be somewhat elusive, is to prevent chronic total are frequently located immediately adjacent to the physis venous occlusion, with subsequent symptoms of pain and and then appear to travel distally as the patient grows. Most swelling. Our approach to venous thoracic outlet syndrome JOURNAL OF VASCULAR SURGERY Volume 53, Number 3 O’Brien et al 813

generally begins with venography and thrombolysis, which 3. Garrison RC, Unni KK, McLeod RA, Pritchard DJ, Dahlin DC. Chon- is followed by early thoracic outlet decompression if the drosarcoma arising in osteochondroma. Cancer 1982;49:1890-7. subclavian vein is patent after lytic therapy. We have gener- 4. Robbin MR, Murphey MD. Benign chondroid neoplasms of bone. Semin Musculoskelet Radiol 2000;4:45-58. ally preferred a supraclavicular or paraclavicular approach to 5. Florez B, Mönckeberg J, Castillo G, Beguiristain J. Solitary osteochon- first rib resection, and in this patient, we felt that the droma long-term follow-up. J Pediatr Orthop B 2008;17:91-4. addition of the infraclavicular incision was critical for 6. Chin KR, Kharrazi FD, Miller BS, Mankin HJ, Gebhardt MC. Osteo- achieving maximal exposure of a very medially placed tu- chondromas of the distal aspect of the tibia or fibula. Natural history and mor. Complete resection with adequate margins was essen- treatment. J Bone Joint Surg Am 2000;82:1269-78. tial in this case of a broad-based osteochondroma to pre- 7. Mollano AV, Hagy ML, Jones KB, Buckwalter JA. Unusual osteochon- droma of the medial part of the clavicle causing subclavian vein throm- vent recurrence. This case demonstrates an excellent bosis and brachial plexopathy. A case report. J Bone Joint Surg Am clinical result with a very unusual cause of pediatric venous 2004;86:2747-50. thoracic outlet syndrome. 8. Filis KA, Nguyen TQ, Olcott C. Subclavian vein thrombosis caused by an unusual congenital clavicular anomaly in an atypical anatomic position. REFERENCES J Vasc Surg 2002;36:629-31. 9. Nelson RM, Hess WE, Lyman JH. Venous obstruction with hypertrophy 1. Kitsoulis P, Galani V, Stefanaki K, Paraskevas G, Karatzias G, Agnantis of an upper extremity due to osteochondroma. Surgery 1963;54:871-4. NJ, et al. Osteochondromas: review of the clinical, radiological and pathological features. In Vivo 2008;22:633-46. 2. D’Ambrosia R, Ferguson AB Jr.The formation of osteochondroma by epiphyseal cartilage transplantation. Clin Orthop 1968;61:103-15. Submitted Aug 19, 2010; accepted Sep 28, 2010.