Choristoma Q89.9

Dysontogenetic tumor resulting from tumor-like proliferation of scattered, non-local tissue (choristia). Exemplary is the occurrence of adrenal germ tissue in the kidney. Choristoma of different provenance are also found in the middle ear (Jančíková J et al. 2021).

Ophthalmologically, choristomas are found in the orbit, cornea, conjunctiva, uvea, retina, and optic nerve. Osseous choristoma is found primarily in the choroid in young female patients. Although considered a benign tumor, it grows progressively and can impair visual function.

A 12-year-old female patient developed spontaneously in 9 months a cystic tumor palpable in the upper eyelid region, partially retrobulbar, which dented the bulb and displaced it inferiorly. The cyst had no connection to the intact orbital wall and could be bluntly detached from the orbit. Histopathologic examination revealed typical upper respiratory tract epithelium. The process was clearly distinguishable from a mucocele of the paranasal sinuses (Henke V et al. 1987).

1. Kim BH et al (2005) Intraocular choristoma. Semin Ophthalmol 20:223-229.
2. Henke V et al (1987) Rhinoepithelial cystic choristoma of the orbit. Clin Monbl Ophthalmol 190: 192-195.
3. Jančíková J et al (2021) Salivary gland choristoma of the middle ear in a child: A case report. Ear Nose Throat J 100 (3_suppl):356S-359.