Locally Malignant Bone Tumors Overview

Locally Malignant Bone Tumors

• Adamantinoma (Mandible & Maxilla): A malignant tumor arising from ameloblasts. Found around the knee, distal femur, and proximal tibia.
• Adamantinoma (Long Bones): A locally malignant tumor, primarily occurring in those over 40.
• Chondroma: A locally malignant tumor (or malignant) mostly occurring in people over 40.
• Osteosarcoma: The most common primary malignant bone tumor.
• Chondrosarcoma: Less common than osteosarcoma.
• Fibrosarcoma: An uncommon bone tumor arising from periosteum.
• Plasma Cell Multiple Myeloma: A malignant tumor arising from plasma cells in bone marrow.
• Ewing's sarcoma: A malignant bone tumor characterized by primitive round cells without any differentiation.

Site and Location

• Adamantinoma: Can occur around the knee, involves the distal femur and proximal tibia, and both epiphyses and metaphyses. Commonly found in the mandible and maxilla.
• Adamantinoma (Long Bones): Primarily located within long bones.
• Chondroma: Commonly found in the sacrococcygeal region.
• Osteosarcoma & Chondrosarcoma: Primarily located around the central portion of the skeleton.
• Fibrosarcoma: Generally found in the femur and tibia.
• Plasma Cell Multiple Myeloma: Originates in bone marrow.
• Ewing's Sarcoma: Often found in the medullary canal of the femur or flat bones of the pelvis.

Gross Features

• Giant Cell Tumor (Osteoclastoma): Eccentric mass eroding cortical bone, covering cortical bone becomes thinned (egg-shell like), brownish, and frequently shows cystic degeneration. Hemorrhage is common.
• Adamantinoma: Oval mononuclear stromal cells, dark nuclei, with various degrees of atypia. Multinucleated giant cells (up to 100 nuclei) that are osteoclastic in type, are also present.
• Chordoma: Infiltrative gelatinous mass, large mass extending within the medullary canal, destroying bone cortex, and extensive hemorrhage/necrosis.
• Osteosarcoma: Usually a firm grayish mass surrounding the bone, and infiltrates the bone cortex and medullary.
• Chondrosarcoma: Grows within the medullary canal.

Microscopic Features

• Giant Cell Tumor (Osteoclastoma): Mononuclear stromal cells, have dark nuclei, with various degrees of atypia, and multinucleated giant cells
• Adamantinoma: Islands of odontogenic epithelium within a fibrous stroma.
• Chordroma: Infiltrative gelatinous mass with various features.
• Osteosarcoma: Pleomorphic spindle cells, and include spindle and giant cells, showing anaplastic features.
• Chondrosarcoma: Hyaline matrix in low-grade tumors, abundant, Myxoid change and spotty calcifications in high-grade tumors. Vascularity and hemorrhage, more obvious in high-grade tumors.
• Fibrosarcoma: Pleomorphic spindle cells with low/high grade nuclear atypia, collagenous matrix, and thin-walled vessels.Hemorrhage and necrosis common in high-grade tumors.
• Plasma Cell Multiple Myeloma: Sheets of uniform, small blue round cells.
• Ewing's Sarcoma: Composed of small blue round cells with scant clear cytoplasm.

Prognosis

• Adamantinoma: Local recurrences after treatment, and distant metastases.
• Chordoma: Poor prognosis.
• Osteosarcoma: Generally better than chondrosarcoma, but local recurrences and distant metastases are still possible.
• Chondrosarcoma: Generally better than osteosarcoma.
• Fibrosarcoma: Slower progression with low grade tumors, but higher grade tumors present poor prognosis.
• Plasma Cell Multiple Myeloma: Varies based on grade but frequently has a worse prognosis.
• Ewing Sarcoma: Varies based on grade but frequently has a worse prognosis.