First description of malignant retrobulbar and intracranial teratoma in a lesser kestrel (Falco naumanni).

Teratomas are defined as germ cell origin neoplasms that can be rarely found in either humans or animals. Their most common localization is the gonads, although extragonadal localization has also been observed. In avian medicine, there is scarce literature about the occurrence of teratomas and their clinical implications, and this is mainly in wildlife birds . For this reason, we report the first description of a teratoma with both retrobulbar and intracranial locations in a 10-day-old chick of a lesser kestrel (Falco naumanni) born in captivity. The raptor was treated in a centre of wildlife rehabilitation because of the presence of left periocular swelling and exopthalmos. The bird worsened rapidly with signs of vestibular syndrome, ataxia and depression, and euthanasia was practised for humanitarian reasons. Histological examination characterized both masses as malignant teratomas based on the presence of tissues of the three germ cell layers and the presence of both anaplastic foci and immature tissues.