Malignant Tumors of Bone MCQs

Chondrosarcoma A chondrosarcoma is a malignant tumor derived from cartilage cells and it tends to maintain its cartilaginous character throughout its evolution. Highest incidence is in the fourth and fifth decades and men are affected more often than women. Most commonly involved bones are pelvis(most common), femur(2 nd most common), humerus, ribs and shoulder girdles. It may be at metaphysis or diaphysis. This tumor is slow growing but can metastasise to distant site The usual presentation is dull ache or gradually enlarging mass. Radiological features Expansile, radiolucent lesion in the medullary cavity(concentric) Endosteal scalloping. Punctate comma shaped or popcorn calcification. Treatment Surgery is the treatment of choice Reference: Campbell, 12 th edition, Page no. 914.

The drugs used in T 10 protocol include High dose Methotrexate Bleomycin Dactinomycin Doxorubicin Cyclophosphamide Reference: Miler's 8th Edition of Review of Orthopaedics, page no. 1854

The diagnosis is chondrosarcoma. The points in favor are The age of the patient is 45 years. The common age for chondrosarcoma is between 40 to 60 years. The site of origin is the metaphysis. The x ray finding of endosteal scalloping and punctate calcification is seen in chondrosarcoma. Osteosarcoma and Chondroblastoma are commonly seen in the 2nd decade of life Metastasis does not produce endosteal scalloping and punctate calcification Reference: Miler's 8th Edition of Review of Orthopaedics, page no. 1885

Poor prognostic factors for Ewing's sarcoma Distant metastases Advanced and extensive disease with fulminant course. Large tumor size(> 8cm) Proximal location Older age(> 17 years) Male gender Genetic aberrant P-53 expression Relapse Early(within Poor response to chemotherapy Elevated ESR, WBC, LDH value indicates more extensive disease and poor prognosis. Ewing sarcoma is the most chemosensitive and most radiosensitive malignant bone tumor. Ewing sarcoma(> osteosarcoma) is the most common tumor showing bone to bone metastasis, hence mandating a bone scan to detect the metastasis. Reference: Maheshwari Essential Ortho, 5 th edition, Page no. 243.

Metastasis is the most common malignancy of the skeleton, but multiple myeloma is the most common primary malignancy of the skeleton. Osteochondroma is the most common benign tumor of the skeleton. Reference: Maheshwari Essential Ortho, 5 th edition, Page no. 247.

The most common radiation induced tumour is osteosarcoma. Such tumors are called secondary osteosarcoma. They have a very poor prognosis. The most common radiation induced benign tumour is osteochondroma. Reference: J. Maheshwari's 5th Edition of Essential Orthopaedics page no. 242

Bone-forming tumours are a sub-set of bone tumours that are characterised by their propensity to form excess osteoid. They can be further subdivided into benign and malignant tumours. Benign tumours Osteoid osteoma Osteoblastoma Bone island(enostosis) Osteopoikilosis Osteoma Malignant tumours Malignant bone-forming tumours are all osteosarcomas. Osteosarcoma(conventional) Telangiectatic osteosarcoma Low-grade central osteosarcom Reference: Adam's Outline of orthopedics, 14th edition, Pg: 113.

Adamantinoma is a low grade malignant tumor most commonly affecting the tibia. It is a diaphyseal tumor. Tibia (85% cases) followed by fibula is the most common site for adamantinoma of long bones. It occurs between 20 to 40 years of age. The swelling is associated with only minimal pain and it increases in size gradually. Typically, it appears as a honeycomb-like, loculated lesion on X-ray. Metastasis is not common. Treatment is by resection. Reference: Maheshwari Essential Ortho, 5 th edition, Page no. 237.