The diagnostic significance of pulmonary nodules on CT thorax in chondrosarcoma of bone.

AIM

To provide a diagnostic approach to pulmonary nodules in patients with chondrosarcoma.

MATERIALS AND METHODS

A search of the oncology database at a specialist orthopaedic oncology referral centre was performed to identify all patients who were treated surgically for chondrosarcoma between January 2007 and December 2018. Reports from the computed tomography (CT) examinations of the thorax of these patients were reviewed. In patients who had pulmonary nodules/metastases identified on CT, data on the primary chondrosarcoma and pulmonary nodule characteristics were collected.

RESULTS

Twenty point two percent of patients had a pulmonary nodule identified on either initial or follow-up staging CT of the thorax, of which 8.1% were pulmonary metastases. Patients with grade 3 and dedifferentiated chondrosarcoma were more likely to have pulmonary metastases than patients with grade 1/2 chondrosarcoma. The time interval to developing metastases was shorter in patients with grade 2/3 and dedifferentiated chondrosarcoma versus patients with grade 1 chondrosarcoma. A low proportion of patients with grade 1 chondrosarcoma developed metastases (12.5%), all of which were identified at the time of a local recurrence. Nodules ≥10mm, nodules with lobulate margins, nodules containing irregular or subtle calcification, and nodules seen bilaterally or both centrally and peripherally were more likely to represent pulmonary metastases than benign nodules.

CONCLUSION

The diagnostic significance of pulmonary nodules (i.e., whether they represent pulmonary metastases or not) can be predicted by taking into account a number of factors, in particular, the histological grade of the patient's chondrosarcoma, the size and margins of the nodules, and the presence of subtle/irregular calcification.