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[Frontal aneurysmal bone cyst. A case report and review of the literature].

INTRODUCTION
Cranial aneurysmal bone cyst (ABC) is a rare pathological finding that is usually diagnosed in young patients. It is defined as a benign lesion made up of intervillous spaces limited by connective bone tissue septa and osteoclast-type giant cells; these histological characteristics are common to extracranial ABC. Clinically, in most patients, they manifest as cranial tumours which may be painful and vary in size. About 100 cases of cranial ABC have been reported in the literature. We present a literature review of the cases of frontal ABC reported to date, including one that was recently treated in our own service.


CASE REPORT
A 29-year-old female, with no history of traumatic brain injury, who was examined due to the presence of a fixed, painless frontal cranial lesion on the right-hand side. The results of a radiological study revealed the presence of a lytic cranial lesion with well-delimited edges and marginal sclerosis; peripheral and linear contrast enhancement was also observed in the magnetic resonance imaging of the brain. The patient was submitted to a surgical intervention and the entire lesion was removed. There were no incidents in the post-operative period and the definitive pathological diagnosis was cranial ABC.


CONCLUSIONS
Cranial ABC is a pathological condition with well-defined histological and radiological characteristics, despite the fact that its aetiopathogenesis is still not fully understood. Complete excision of the tumour is considered to be the preferred treatment, which often leads to full recovery of the patient and also offers a good long-term prognosis.