Presentation
Right leg pain and swelling for 8 months.
Patient Data
A large well-defined, expansile lytic lesion involving right tibial proximal metadiaphysis. Surrounding cortical thinning is noted. No internal calcification.
This lesion shows internal fluid-fluid levels.
No aggressive periosteal reaction is noted.
No extension beyond the tibial contour.
No extension to the soft tissues.
No significant involvement of the epiphysis.
A large expansile lytic lesion of the right proximal tibial meta-diaphysis. The lesion demonstrates high signal on T2-weighted images and an intermediate to high signal on T1-weighted images with fluid-fluid levels. Some loculi of the lesion show dependent diffusion restriction. In post-contrast images, there is evidence of septal enhancement of the lesion.
No significant solid components are seen in the lesion.
No extension to soft tissues.
No extension to the knee joint.
Some edema is seen in the epiphysis.
Case Discussion
The patient underwent surgery under general and caudal anesthesia. Lavage and biopsy of the cystic lesion were taken. The epiphyseal end of the cavity was bone grafted (from iliac bone) and the rest of the cavity was filled with bone cement.
Microscopic findings were: multiple fibro-osseous and fibro-collagenous tissue fragments showing bony trabeculae with interspersed bone marrow, variable-sized blood-filled spaces separated by fibrous septae with acute and chronic inflammation comprised of neutrophils, lymphocytes, plasma cells, histiocytes and multinucleated giant cells. No evidence of granuloma or malignancy is seen in the sections examined.
The radiological and histopathological features were compatible with aneurysmal bone cyst.
Acknowledgement:
Thanks to Dr. Royeen Dehzad, Orthopedic surgeon for providing the surgery details.
Thanks to Dr. Jamshid Jalal, consultant Histopathologist for providing the pathology details.
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