Presentation
Right thigh pain and difficulty walking for the past 2 months.
Patient Data
Expansile destructive lytic lesion involving the sacral spine, i.e. S1, S2, and S3 vertebral bodies, with posterior extension to posterior elements and spinal canal, measuring about 8 x 5 x 7 cm (AP x TR x CC), associated with pathological fracture of S1 vertebral body. Slight extension to left sacroiliac joint.
Findings favor an aggressive bone tumor.
Large, relatively well-defined mass involving the sacral spine, as seen on the above CT, extending to the presacral space, predominantly the left side, but separable from the rectum and pelvic organs.
The mass demonstrates isointensity on T1WI, heterogeneous (i.e. intermediate SI with multiple high-signal foci) on T2WI, not suppressed on fat sat sequences and showing homogeneous enhancement after contrast administration.
Findings in favor of an aggressive bone tumor.
The above two biopsies has been done in two different countries by the best two different pathology centers where the gave the same result.
Case Discussion
Solid variant of ABC is an uncommon neoplasm seen in young patients. It differs from the classical type of ABC in certain aspects. The exhibits clinical as well as radiological features of a malignant bone tumor. The aggressive radiological features lead to the wrong diagnosis in most of the cases.
Biopsy result:
Microscopic description: section showed cores of tissue composed of cellular lesion composed of mixed population of bland looking spindle cells and ovoid cells with fibroblastic morphology admixed with numerous multinucleated giant cells of osteoclast morphology.
The cells have rather uniform nuclei.
The cells have mostly distributed in solid sheets with occasional small blood filled spaces have no true epithelial lining.
A rich thin walled blood vessels were seen in the background.
No osteoid deposition were seen.
No significant atypia or pleomorphism was seen.
Mitotic figures were few, not more than 1 per 10 hpf, atypical forms were absent.
No necrosis was present.
Conclusion:
Sacral mass core biopsy consistent with giant cell-rich bone lesion featuring low grade histological features.
Considering the patient age, radiological features and giant cell rich bone histological findings, solid variant of aneurysmal bone cyst (ABC) is the most likely possibility.