Other malignant tumors

Fibrosarcoma

Overview

• Very similar to Osteosarcoma in features.

Epidemiology

• Usually affects individuals >40 years.
• Rare condition.

Clinical Features

• Pain and swelling, often presenting as a mass.
• Locations are similar to Osteosarcoma.

Imaging

• Purely lytic lesions with:
  • Periosteal reaction.
  • Cortical destruction.
  • Indistinct margins.
  • Soft tissue mass often associated.

Pathology

• Spindle cells arranged in a herringbone pattern.
• Grading can vary.

Management

• Prognosis correlates with the grade.
• Treated like Osteosarcoma, including responsiveness to chemotherapy.

Malignant Fibrous Histiocytoma (MFH)

Clinical Features

• Similar to Osteosarcoma but does not produce osteoid.

Epidemiology

• Typically occurs in individuals >40 years.

Aetiology

• Usually develops de novo.
• 25% occur secondary to Paget's disease or post-radiation.

Clinical Presentation

• Pain, swelling, and mass as seen in Osteosarcoma.

Imaging Features

• Aggressive lytic lesion with:
  • Ill-defined margins.
  • Periosteal reaction.
  • Soft tissue mass and cortical breach.
  • No bone production.

Pathology

• No osteoid or spindle cells.
• Features include:
  • Large, irregular, multinucleated nuclei with a storiform appearance.

Management

• Similar to Osteosarcoma, as it is chemo-sensitive.
• Outcomes are slightly worse than Osteosarcoma, especially in secondary MFH.

Chordoma

Epidemiology

• Men are affected three times more than women.
• Usually occurs in individuals >40 years old.

Aetiology

• Arises from remnants of notochordal cells undergoing neoplastic changes.

Clinical Features

• Always occurs in the midline spine:
  • 50% sacrum (below S1 usually).
  • 35% cranio-occipital region.
  • 15% axial spine vertebrae.
• Can metastasize late, typically to the lungs.

Presentation

• Cranial lesions present earlier.
• Sacral lesions cause slow-growing pelvic masses, with possible GI and genitourinary symptoms.

Imaging Features

• X-ray: Hard to interpret; shows sacral mass with calcification and bony destruction.
• MRI: Low signal on T1, high signal on T2.

Pathology

• Hallmark: Physaliferous cells (keratin-filled lobular cells).
• Globular and soft macroscopically.

Management

• Wide excision is preferred.
• Chemotherapy is ineffective.
• Radiotherapy is used for inadequate margins but not as a primary treatment.

Outcomes

• High local recurrence rates due to difficulty achieving clean margins.
• Long-term survival is approximately 50%.

Lymphoma (Primary Lymphoma of Bone)

Epidemiology

• Affects any age but typically middle-aged adults.
• Males are more commonly affected.

Aetiology

1. Primary Lymphoma:
   • Solitary bone lesion with no more than a single node.
   • Rare condition.
2. Secondary Lymphoma:
   • Skeletal metastases from systemic B-cell lymphoma (most common).

Clinical Features

• Large, warm, soft tissue mass.
• Swollen, painful lymph nodes.
• Hallmark systemic symptoms: weight loss, fever, night pain.

Location

• Bones with persistent red marrow, such as the femur, pelvis, and vertebrae.

Imaging Features

• Large permeative lytic lesions with a mottled appearance.
• High uptake on bone scan.

Pathology

• Small round blue cells, typically B cells.
• Positive for CD20 and CD45 on immunohistochemistry staining.

Management

• Multiagent chemotherapy is primary.
• Radiotherapy is used for chronic control.
• Surgery is for fracture prevention or treatment only.

Outcomes

• Prognosis is approximately 70%, better for primary lymphoma of bone.

Multiple Myeloma

Epidemiology

• Most common malignant bone tumor.
• Men are more commonly affected than women.
• Blacks are affected more frequently than whites.
• Typically occurs in individuals >50 years.

Aetiology

• Disease of bone marrow plasma cells.
• Produces abnormal light and heavy protein chains.
• Osteoblasts are inhibited, while osteoclasts are stimulated.

Clinical Features

• Bone pain and pathologic fractures, especially in the spine.
• Systemic features: renal failure and hypercalcemia.

Location

• Areas with red marrow:
  • Skull.
  • Vertebrae.
  • Ribs.
  • Pelvis.
  • Femur.

Imaging Features

• Punched-out lytic lesions with no sclerotic rim.
• Multi-site involvement.
• Bone scans are negative due to osteoblast inactivation.

Pathology

• Bence Jones proteins: Light chains in urine.
• Elevated serum immunoglobulin: Heavy chains.
• High plasma cell count in blood film and bone biopsy.

Management

• Chemotherapy is primary.
• Radiotherapy for pain relief.
• Surgery for fracture prevention or vertebroplasty/kyphoplasty.

Myeloma Subtypes

1. Solitary Plasmacytoma:
   • Single lesion with better prognosis.
2. Osteosclerotic Myeloma:
   • Associated with POEMS syndrome:
     • Polyneuropathy.
     • Organomegaly.
     • Endocrinopathy.
     • M spike.
     • Skin changes.

Ewing’s Sarcoma

Epidemiology

• Affects men more than women.
• 80% occur in individuals under 20 years old.

Aetiology

• Unknown.
• Considered a dedifferentiated Primitive Neuro-Endocrine Tumor (PNET).

Clinical Features

• Pain and fever, mimicking infection.
• Large soft tissue mass.
• Often metastasizes to lungs and bones.

Location

• Pelvis, long bones, spine, scapula.
• May occur in diaphyseal or metaphyseal regions.

Imaging Features

• Purely lytic lesion with moth-eaten appearance.
• Concentric periosteal reaction ("onion skin").

Pathology

• Blue-stained round cells.
• Chromosomal translocation (11:22).
• CD99 antigen positivity.

Management

• Neo-adjuvant chemotherapy.
• Wide local excision.
• Tumors are radiosensitive, but surgery is preferred.

Outcomes

• Survival for solitary lesions without metastases: 70% at 10 years.
• Poor prognostic factors:
  1. Metastases at presentation (<20% survival).
  2. Tumor necrosis <90% after chemotherapy.
  3. High LDH levels.
  4. Large tumor load.
  5. Pelvic tumors (difficulty achieving control).

Adamantinoma

Epidemiology

• Rare, low-grade malignant tumor.
• Affects young adults, with men more commonly affected.

Aetiology

• Unknown; may arise from cortical fibrous dysplasia.

Clinical Features

• Long-standing pain and swelling.
• Occasional soft tissue mass.
• Late metastasis to lungs.

Location

• Tibia (90%), particularly diaphysis.

Imaging Features

• Multiple lytic areas interspersed with sclerosis.
• Soap bubble appearance.

Pathology

• Epithelial-type cells in a palisading arrangement.

Management

• Wide local excision and reconstruction.
• Chemotherapy and radiotherapy are ineffective.

Outcomes

• 90% survival at 10 years.