Images of Musculoskeletal Oncology

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Osteomyelitis

A 10 year old boy has had left thigh pain for several months. There was no history of symptoms suggesting infection, such as thigh redness or fever. Tenderness was noted over the distal femoral metaphysis.

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	The lateral routine radiograph demonstrates an osteolytic lesion with surrounding reactive bone in the distal metaphysis. A smooth border of periosteal new bone is present. The adjacent bone and knee joint appears normal. The appearance is most compatible with infection, but malignant neoplasm cannot be ruled out.
	The AP MRI demonstrates the extent of the intraosseous lesion and the peripheral reaction both within the medullary canal and out into the soft tissues. These findings are most in keeping with a large abscess and osteomyelitis with extensive reaction of the surrounding tissues.
	The cross section MRI clearly demonstrates the intramedullary and extracortical involvement of the infection.
	The microphotographs of the tissue from the center of the intramedullary abscess demonstrates necrotic inflammatory cells. Staphylococcus aureus was grown from this lesion.

The abscess was incised, drained, and debrided. Appropriate antibiotics were used.

Learning Issues: 1. Although infection is often included in the diagnosis of bone tumor, attention to what the lesion is doing to the bone and how the bone reacts to the lesion can often lead to the correct diagnosis. 2. A bone abscess may be dormant clinically and detected only by careful attention to detail. In this case, the pus was truly laudable as some clinicians suspected a malignant tumor.

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Images of Musculoskeletal Oncology

University at Buffalo Department of Orthopaedics

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