Mesenchymal chondrosarcoma is a malignant neoplasm arising
from cartilaginous bone or soft tissue. It is uncommon yet
devastating. Our patient was a 21-year-old man who presented
with pleuritic chest pain and weight loss. His chest radiograph
showed left pleural effusion. His pleural effusion analysis was
consistent with exudative pleural effusion. Tuberculosis
workup was negative. Pleural fluid cytology did not yield
malignant cells. Subsequently, his computed tomography of
thorax showed left rib sclerotic lesion with soft tissue
component. Biopsy of the soft tissue eventually confirmed the
diagnosis of mesenchymal chondrosarcoma. He succumbed to
his illness before the diagnosis was confirmed. We hope that
through this case report, we are able to provide some insight
into this rare condition.