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.
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