Presentation
Neck pain
Patient Data
A mass involving primarily the posterior elements of C7 with destruction of the bone has vivid enhancement and multiple cystic spaces some of which have fluid-fluid levels. There is extension into the epidural space with narrowing of the canal and displacement of the cord, without cord compression.
Single axial CT slice through the C7 vertebral body demonstrates bony destruction with a thin rim of residual bone posteriorly further supporting that this lesion originated in the posterior elements.
Case Discussion
The patient went on to have a resection.
Histology
The sections show portions of the bony lesion, as well as adjacent involved soft tissue, including fibrous tissue, fibrofatty tissue and skeletal muscle. Lesional tissue is present within adjacent soft tissue and replaces and partly compresses it. There is a partial peripheral component of formation of osteoid trabeculae which have focal calcification and show osteoblastic rimming. This pattern merges with myxoid spindle-celled tissue. Internal to this is a cellular component of osteoclast-like giant cells, with oval but variably sized nuclei and quite prominent single nucleoli. There is an intervening spindle cell population, with some cells showing similar nuclei to those of the giant cells. There are ectatic blood-filled spaces, with areas of hemosiderin-laden macrophages. Foci of myxoid spindle cell proliferation are associated with variable osteoid deposition. Zones of collagenous fibrous tissue are also present. The background spindle cell population is generally mildly pleomorphic only. Occasional foci of chronic inflammatory cell infiltration are also noted. No malignancy was identified.
Final diagnosis
Giant cell tumor of bone with associated aneurysmal bone cyst-like changes.
Note: unfortunately H3.3pGly34Trp status is not available for this case. Aneurysmal bone cysts do not express H3.3pGly34Trp, a feature that can be used to differentiate them from giant cell tumors of bone with aneurysmal bone cyst-like changes which do not.