{'fraction_non_alphanumeric': 0.022604422604422605, 'fraction_numerical': 0.004914004914004914, 'mean_word_length': 5.245398773006135, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Chondrosarcoma in a patient with osteogenesis imperfecta

A 29-year-old woman who has been diagnosed with osteogenesis imperfecta type 3 in childhood, presented with a large painless mass in her right knee. She did not walk independently and mobilized with the aid of an electric wheelchair. The mass had been identified incidentally on a recent plain radiograph by the referring doctor (Fig. 1), and was not obvious clinically due to body habitus. She was systemically well, with a large immobile non-tender mass in the right knee region. The right leg was neurovascularly intact, and no other abnormalities were detected clinically. A whole-body technetium bone scan was performed, displaying an increase in radionucleotide uptake localized to the mass (Fig. 2). Ideally, a computed tomography scan and/or a magnetic resonance imaging (MRI) would be part of our investigation but the patient was unable to tolerate these procedures due to her underlying osteogenesis imperfecta which restricted her ability to lie supine or still and concerns for her safety in a magnet with considerable metalwork of doubtful stability. A 5-mm trephine biopsy was performed, which returned a histological diagnosis of benign enchondroma. Due to the appearance and size of the lesion, chondrosarcoma was suspected. An open biopsy was then performed, returning a pathological diagnosis of grade 1 chondrosarcoma (Fig. 3). The unique difficulties of reconstructive options following wide excision were discussed with the patient in this case, who elected for above knee amputation. This procedure was performed without incident, and excision margins were clear. Review of the histology of the entire specimen confirmed the presence of invasive chondrosarcoma (grade 1). The patient remains free of disease on continuous review currently at 5 years post-operatively. Chondrosarcomas are malignant tumours of cartilage tissues which may arise primarily or secondarily in enchondromas or osteochondromas, particularly in inherited conditions characterized