Orbital lipomatous haemangiopericytoma: an unusual variant.

Haemangiopericytoma (HPC) of the orbit is a rare tumour occurring in all age groups and presenting with slowly progressive proptosis, ocular motility impairment and visual loss. Although most are benign tumours that are resectable at diagnosis, one-third of these tumours demonstrate malignant features and recur locally or metastasize, usually with a fatal outcome. In 1995, a morphologically unique variant, termed lipomatous haemangiopericytoma (L-HPC), was described. Only one case has been reported previously arising in the orbit. In this paper, a case is reported of L-HPC occurring in the orbit and consider the prognostic implications of this HPC variant.