Intraorbital Retrobulbar Salivary Gland Choristoma: Presentation of a Unique Case and Review of the Literature.

Background:  A choristoma is defined as the accumulation of normal tissue in an abnormal location. Salivary gland choristomas are a rare entity that is most frequently described in the middle ear. However, there are a few reported cases of salivary gland choristomas in other locations like the pituitary gland and the optic nerve dural sheath. To the best of our knowledge, we present the first case of a patient with an intraconal salivary gland choristoma. A brief but comprehensive review of literature is offered, additionally.

Methods:  A 19-year-old male patient presented with disturbance of ocular motility, ptosis, and exophthalmos of the right eye. The subsequent imaging by magnetic resonance imaging (MRI) demonstrated an intraconal lesion that infiltrated the lateral and medial rectal muscles of the right eye. The lesion showed intensive gadolinium enhancement in T1-weighted sequence and the fluid-attenuated inversion recovery (FLAIR) sequence showed no intracranial edema. The interdisciplinary neuro-oncologic tumor board recommended a biopsy and partial removal of the lesion.

Results:  Partial resection of the choristoma was successfully performed via lateral orbitotomy. No new neurologic or visual deficits occurred postoperatively. During the 2-week follow-up examination, the exophthalmos had completely regressed and the patient only reported a slight retrobulbar pressure sensation. The histopathologic examination of the tissue revealed seromucous glandular tissue.

Conclusion:  Salivary gland choristomas have been occasionally described intracranially before, but this is the first case of an intraconal accumulation of salivary gland tissue. Partial resection was achieved, resulting in complete recovery of the ophthalmologic symptoms.