Presentation
Leg pain with swelling for 1 year. No previous history of trauma.
Patient Data
A T1 iso and T2/PDFS heterogeneously hyperintense expansile eccentric lesion measuring approx. 3.6 x 3.7 cm is noted in the metaphysis of lower end of right tibia which is extending into epiphysis and abutting the articular surface. The lesion is causing thinning of overlying cortex with focal cortical disruption in anterolateral aspect. It has a narrow zone of transition. Fluid-fluid level is noted in the anteroinferior aspect of the lesion on T2/PDFS. Moderate heterogeneous enhancement is noted on post-contrast study.
Patchy marrow oedema noted in the subarticular region of cuboid with T1 linear hypointense line suggests stress fracture.
Case Discussion
An expansile eccentric lesion in a subarticular location with soft tissue component and fluid-fluid level showing moderate enhancement on the post-contrast study suggests giant cell tumour with secondary aneurysmal bone cyst.
FNAC from the lesion shows a double population of cells consisting of mononuclear spindle cells and many osteoclastic giant cells.