A 49-year-old woman with no significant past medical history presented to her primary care physician complaining of an enlarging palpable mass along the midline of her upper chest.
Axial (A, B) and sagittal (C) noncontrast CT images of the chest demonstrate a lytic and expansile lesion of the sternum with lobulated margins. An arc-like matrix pattern (red arrows in A, B, C) is demonstrated within various portions of the lesion.
The sternum is a flat bone in the axial skeleton, that houses hematopoietic marrow throughout adulthood. This characteristic makes it a site prone to hematogenous spread of infection or malignancy. The most common malignant process involving the sternum is metastatic disease due to primary breast, lung, thyroid, renal, or prostate malignancy.1,2 Primary neoplasms of the sternum are uncommon. The most common primary neoplasm arising from the sternum is a chondrosarcoma.1,2
CT is the modality of choice in evaluating masses involving the sternum due to its multiplanar capabilities and its ability to assess for mediastinal invasion.1 As in the consideration of any bone neoplasm, patient demographics, site of involvement, pattern of bone destruction, matrix mineralization, and multiplicity of lesions are of utmost importance in narrowing the differential diagnosis.
The treatment of choice in cases without metastatic disease includes wide local excision with cosmetic reconstruction of the anterior chest wall. The pathologic diagnosis was consistent with a well-differentiated, low-grade chondrosarcoma.
Gazaille R, Evans J. JAOCR at the Viewbox: Chondrosarcoma of the Sternum. J Am Osteopath Coll Radiol. 2020;9(4):32.