A-10 yr-old male child presents with pain around the left knee joint. On x-ray, there is a lesion at distal femur extending upto terminal end. Following pathological image of the patient is given. What is the most probable diagnosis?

Correct Answer � A Explanation

Answer A) Osteosarcoma

• Image represents-Typical gross appearance of osteosarcoma involving the distal femoral metaphysis. The tumor has destroyed the epiphyseal plate and extends almost down to articular cartilage. There is also a soft-tissue mass.

^Osteosarcoma

• ^{Osteosarcomas are malignant bone-forming tumors. They are the second most common primary bone tumor after multiple myeloma, accounting for ~20% of all primary bone tumors.}

Epidemiology

• Primary osteosarcoma typically occurs in young patients (10-20 years) with 75% taking place before the age of 20 because the growth centers of the bone are more active during puberty/adolescence. There is a slight male predominance.

Location

Primary osteosarcomas typically occur at the metaphysis of long bones in the appendicular skeleton, most commonly at the following sites:

• femur: ~40% (especially distal femur)

• tibia: ~16% (especially proximal tibia)

• humerus: ~15%