Hybrid neurofibroma/schwannoma of the orbit.

Hybrid neurofibroma/schwannoma is a rare variant of hybrid peripheral nerve sheath tumours (HPNST). A Medline search up to December 2021 identified only six cases of this tumour in the orbit. We report the case of a 78-year-old man who presented with left exophthalmos. Computed tomography showed a left intraconal orbital mass. The clinico-radiological diagnosis was consistent with an intraconal cavernous angioma. Orbitotomy was performed, obtaining an 18×16×11mm mass. Two different morphologies were seen microscopically, diagnostic of hybrid neurofibroma/schwannoma. HPNSTs of the orbit are uncommon and most reported cases showed a hybrid neurofibroma/schwannoma morphology. Hybrid neurofibroma/schwannomas have been associated with neurofibromatosis and schwannomatosis. Local recurrences have been reported. The correct identification of these tumours is important due to their potential use as a syndromic marker.