Secondary chondrosarcoma arising from osteochondroma

Aims The aim of this study was to report the outcomes of patients who underwent definitive surgery for secondary chondrosarcomas arising from osteochondromas. Patients and Methods A total of 51 patients with secondary chondrosarcomas occurring from osteochondromas were reviewed. Median age was 36 years (interquartile range (IQR) 15 to 82). Median follow-up was 6.9 years (IQR 2.8 to 10.6). The pelvis was the most commonly affected site (59%). Histological grades were grade I in 35 (69%), grade II in 13 (25%), and grade III in three patients (6%). Results Preoperative biopsy histology correctly predicted the final histological grade in 27% of patients. The ten-year disease-specific survival (DSS) for all patients was 89.4%. Local recurrence occurred in 15 patients (29%), more commonly in pelvic tumours (37%) compared with limb tumours (19%). Four patients with pelvic tumours died from progression of local recurrence. No patient with limb tumours died of disease. Wide/radical margin was associated with improved local recurrence-free survival (p = 0.032) and local recurrence was associated with worse DSS (p = 0.005). Conclusion We recommend that a secondary chondrosarcoma arising from osteochondroma of the pelvis is resected with wide/radical resection margins. The balance between the morbidity of surgery and risk of local recurrence needs to be considered in patients with limb secondary chondrosarcomas. Cite this article: Bone Joint J 2019;101-B:1313–1320

Secondary Chondrosarcoma Presenting with Symptoms Similar to Thoracic Outlet Syndrome

Thoracic outlet syndrome (TOS) is caused by heterogeneous factors that compress the brachial plexus and subclavian artery; tumor is rarely a cause of TOS. Here, we present the case of a 26-year-old man with secondary chondrosarcoma arising from osteochondroma of the left clavicle causing TOS, with a direct compression of the brachial plexus and subclavian artery. Immediately after surgery, the symptoms of TOS reduced. To our knowledge, this is the first case of a secondary chondrosarcoma of the clavicle causing TOS, which is possibly the key symptom for diagnosing malignant transformation of osteochondroma of the clavicle.

Proximal epithelioid sarcomatous dedifferentiation in secondary chondrosarcoma in a known case of multiple osteochondromatosis

Osteochondroma is the most common benign bone tumor. Approximately 15% of osteochondromas occur as multiple lesions. Multiple osteochondromatosis has a higher risk of developing chondrosarcomas, which are of low grade with good prognosis. About 10% of all chondrosarcomas may undergo dedifferentiated change, which has a poorer prognosis. Dedifferentiated peripheral chondrosarcoma developing within an osteochondroma is extremely rare. Dedifferentiation usually occurs in the form of osteosarcoma, malignant fibrous histiocytoma, fibrosarcoma, or rhabdomyosarcoma. We report a case of proximal epithelioid sarcomatous dedifferentiation in secondary chondrosarcoma in a 39-year-old male with multiple osteochondromatosis in bilateral arm. To the best of our knowledge, epithelioid sarcomatous dedifferentiation has not been described in the literature.

Difficulty in Diagnosing Secondary Peripheral Chondrosarcoma: Radiology versus Anatomical Pathology

Chondrosarcoma is a malignant tumor derived from bone cartilage. This tumor can be either primary or secondary. Secondary chondrosarcoma has some differences compared to the primary type i.e. the incidence is rarer, the younger age group, and many are low grade. The authors report a case of a 26-year-old man came to Hasan Sadikin Hospital with a chief complaint of a lump in the right thigh with mild pain since 5 months before consulation that is increasingly enlarging. After undergoing physical and radiological examinations, the patient was diagnosed with suspect chondrosarcoma in right thigh. Histopathologic examinations were performed 2 times, one of which used ultrasound guidance, giving a diagnosis of chondroma in right thigh. However the lesion was finally treated as chondrosarcoma. We suspected that the patient was more likely to suffer from secondary peripheral chondrosarcoma originating from malignant transformation of multiple osteochondromas. As widely known, it is almost impossible to differentiate between the low grade chondrosarcoma and chondroma with full certainty and this poses a classical problem in diagnostic medicine. Case described here was an example of the difficulty in distinguishing between these two diseases. Key words: secondary chondrosarcoma, peripheral chondrosarcoma, chondrosarcoma arising in osteochondroma