Findings

At high power, note the finely woven, eosinophilic osteoid surrounded by bone forming tumor cells with pleomorphic and hyperchromatic nuclei. On the right is a gross view of the tumor invading the long bone. Note a large, poorly-demarcated lesion situated within the metaphysis which has destroyed the bony cortex, extended inward into the bone marrow and outward into the adjacent soft tissue.

Impression

Osteosarcoma

Clinical Pathologic Correlation
This tumor usually occurs in young individuals (most often in the second decade) and arises most commonly around the knee (distal femur and proximal tibia). Diagnosis requires the identification of osteoid formation, which is the hallmark of this tumor.

Pathology Pointer

Osteosarcoma usually arises de novo, but it may occur as a complication of an underlying bone disorder.

Preparation

Fixed, decalcified, H & E stain; Fresh

View

Gross; Light Micrograph

Specimen

Neoplasm of the bone

Image Credit

Parviz Haghighi, M.D.
Department of Pathology
School of Medicine
University of California, San Diego