Presentation
3-month history of non-traumatic left knee pain.
Patient Data
Rounded lucency in the medial epiphysis of the proximal tibia. Appearances most in keeping with chronic infection.
The lucency demonstrated on the plain film represents a septated, multi-focal fluid-collection in the epiphysis. There is surrounding edema that extends across the physis into the metaphysis. There is the impression of developing abscess in the metaphysis also.
Pathology report
The overall features are those of marrow fibrosis with a patchy chronic inflammatory infiltrate and granulation tissue formation in keeping with acute on chronic osteomyelitis and compatible with an infection, assuming this fits with the clinical presentation and radiological findings. There is no evidence of atypia or malignancy.
Case Discussion
Acute on chronic infection was confirmed pathologically which confirms the appearances on plain film and MRI.