Malignant transformation in an 11-year-old child with multiple hereditary exostosis

ABSTRACT BACKGROUND: Multiple hereditary exostosis (MHE) is a rare autosomal dominant disorder predisposing to the development of multiple osteochondromas. Malignant transformation is an uncommon complication of osteochondromas and is especially rare in the paediatric population. Making a diagnosis of malignant transformation is recognised as a challenge globally METHODS: We obtained informed consent and ethics approval prior to reviewing the hospital file, radiology and pathology of our index patient, as well as conducting a directed literature search RESULTS: An 11-year-old male with MHE presented with new onset pain in the right leg with an associated inability to weight bear. Plain radiographs and magnetic resonance imaging (MRI) showed features consistent with malignant transformation. The child underwent a Malawer 1 resection of the proximal fibula with no complications. The pathology confirmed a grade 1 secondary peripheral chondrosarcoma (CS) arising in an osteochondroma The rate of malignant transformation in MHE is as high as 36.3% in select specialist tertiary centres. Ninety per cent of the resultant malignancies are chondrosarcomas. Malignant transformation before the age of 20 years is exceptional. Plain radiology is routinely used for monitoring of patients with MHE. Other modalities exist to assess for cartilage cap thickness, a much-debated criterion of malignant change. Pathology is essential for confirmation of malignant transformation as well as to exclude high grade lesions. Treatment is wide local excision (WLE) with limb-sparing surgery and long-term follow-up to detect for local recurrences. CONCLUSION: The malignant transformation of osteochondromas occurs more frequently in individuals with MHE and may even arise in the paediatric population. In the presence of suspicious clinical or radiological features, en-bloc surgical resection and histopathological correlation is mandatory to make the diagnosis. We encourage a multidisciplinary team approach with collaboration between the orthopaedic surgeon, radiologist and pathologist Level of evidence: Level 5 Keywords: multiple hereditary exostosis (MHE), chondrosarcoma, osteochondroma, malignant transformation

Differential Diagnosis of Cartilaginous Lesions of Bone

Context.— Cartilaginous tumors represent one of the most common tumors of bone. Management of these tumors includes observation, curettage, and surgical excision or resection, depending on their locations and whether they are benign or malignant. They can be diagnostically challenging, particularly in small biopsies. In rare cases, benign tumors may undergo malignant transformation. Objective.— To review common cartilaginous tumors, including in patients with multiple hereditary exostosis, Ollier disease, and Maffucci syndrome, and to discuss problems in the interpretation of well-differentiated cartilaginous neoplasms of bone. Additionally, the concept of atypical cartilaginous tumor/chondrosarcoma grade 1 will be discussed and its use clarified. Data Sources.— PubMed (US National Library of Medicine, Bethesda, Maryland) literature review, case review of archival cases at the Massachusetts General Hospital, and personal experience of the authors. Conclusions.— This review has examined primary well-differentiated cartilaginous lesions of bone, including their differential diagnosis and approach to management. Because of the frequent overlap in histologic features, particularly between low-grade chondrosarcoma and enchondroma, evaluation of well-differentiated cartilaginous lesions should be undertaken in conjunction with thorough review of the imaging studies.

Management of extremity arterial pseudoaneurysms associated with osteochondromas

Arterial pseudoaneurysms associated with osteochondromas are rare and most publications on this topic are case reports. The management of this double entity is not standardized. We wanted to update it. Literature searches on MEDLINE and EMBASE were performed using the keywords “artery pseudoaneurysm” and “osteochondroma”. Patient demographics, clinical presentations, diagnostic and therapeutic modalities were reviewed. In sum, 101 cases were analyzed. Overall, young adults represented the majority of the affected population with a masculine preponderancy (86%). Painful swelling (51%) was the most commonly physical finding. Distal femur was the most common site of the osteochondroma (86%). Multiple hereditary exostosis was seldom reported (36%). Diagnostic confirmation was dominated by arteriography (55%). Popliteal artery (77%) was the most commonly injured vessel. The treatment was open surgery with vascular repair and optimal exostectomy. Arterial repair was performed with saphenous vein grafting (40%) or lateral suture (39%). Postoperative courses were often uneventful (97%). Arterial pseudoaneurysms resulted from osteochondromas were dominated by those involving the popliteal artery. The use of arteriography to confirm the diagnosis may be limited to the benefit of non-invasive radiological methods because endovascular treatment is not relevant in the setting of osteochondroma-induced arterial pseudoaneurysm.