A Rare Case of Low-Grade Bilateral Proximal Humerus Chondrosarcomas Managed With Staged Curettage and Cementation.

Low-grade chondrosarcomas are rare malignant cartilaginous tumors with slow growth and low metastatic potential. Bilateral involvement, especially in the proximal humerus, is an exceedingly rare presentation. This report discusses a 45-year-old female patient who presented with intermittent left shoulder pain and was subsequently found to have bilateral proximal humeral masses on imaging. Bilateral contrast-enhanced MRI suggested a diagnosis of enchondroma or low-grade chondrosarcoma. The patient underwent curettage and cementation, first on the left side, followed by the right side four months later. Pathological analysis of the left lesion confirmed low-grade chondrosarcoma. During the second surgery, a frozen section revealed atypical chondromatous cells, with final pathology also supporting the diagnosis of low-grade chondrosarcoma. This case underscores the importance of careful diagnostic evaluation, including imaging and histopathological assessment, to differentiate low-grade chondrosarcoma from enchondroma. The multidisciplinary approach facilitated timely treatment, emphasizing the efficacy of curettage and cementation in managing these rare bilateral lesions while preserving function.