Giant cell tumour and central giant cell reparative granuloma of the skull: do these represent ends of a spectrum? A case report and literature review.

Giant cell tumour (GCT) of bone is an uncommon primary bone neoplasm typically occurring at the epiphyses of long bones in young adults. They are osteolytic neoplasms with approximate local recurrence rates of 25%, and 2% of patients develop pulmonary metastases. These tumours appear very rarely in the skull, with those few reported cases arising predominantly in the sphenoid and occasionally the temporal bones. They demonstrate benign histological features, but are locally aggressive and surgical excision is the treatment of choice. It is widely believed that giant cell tumours should be distinguished from other giant cell lesions, importantly central giant cell reparative granulomata (CGCG) which are thought to have a lower recurrence rate and for which no cases of malignant transformation or metastases have been reported. Investigators have noted that giant cell lesions in the skull bones may be unique and that GCT and CGCG may be part of a spectrum of a single disease process. We present a case of a giant cell tumour of the temporal bone which illustrates and re-emphasises this concept and review the literature on these lesions.