Ovarian Neuroglial Choristoma in a Bitch.

Neuroglial choristomas are rare malformations consisting of heterotopic mature neural tissue at a site isolated from the brain or spinal cord. In human medicine, neuroglial choristomas are predominantly reported in the head and in the neck, except for one recent case reported in a foot of a child. In domestic animals, neuroglial choristomas are exceedingly rare, reported only in the retina of a dog, in the pharynx and in the skin of two kittens, and within the oropharynx of a harbor seal. A three-year-old intact female Jack Russell Terrier presented for elective ovariectomy exhibited a cystic lesion 2 cm in diameter expanding in the right ovary. Histological examination of the lesion revealed a mass composed of well-organized neuroglial tissue. Immunohistochemistry with primary antibodies against GFAP, NSE, and IBA-1 confirmed the neuroglial origin of the mass. At the time of this writing, 7 years after ovariectomy, the dog was clinically normal. Together with a recent case described in the foot of a child, this case confirms that neuroglial choristoma may also be found far from the skull or spine, supporting the hypothesis that they may arise from an early embryological migration defect.