Medulloepithelioma of the optic disc and optic nerve

Last revised by Francesco Buemi on 26 Jan 2022

Citation, DOI, disclosures and article data

Citation:

Buemi F, Gaillard F, Bell D, Medulloepithelioma of the optic disc and optic nerve. Reference article, Radiopaedia.org (Accessed on 19 Apr 2024) https://doi.org/10.53347/rID-96893

DOI:

https://doi.org/10.53347/rID-96893

Permalink:

https://radiopaedia.org/articles/96893

rID:

96893

Article created:

24 Jan 2022, Francesco Buemi ◉

Disclosures:

At the time the article was created Francesco Buemi had no recorded disclosures.

View Francesco Buemi's current disclosures

Last revised:

26 Jan 2022, Francesco Buemi ◉

Disclosures:

At the time the article was last revised Francesco Buemi had no recorded disclosures.

View Francesco Buemi's current disclosures

Revisions:

4 times, by 3 contributors - see full revision history and disclosures

Systems:

Central Nervous System

Synonyms:

Diktyoma of the optic disc and optic nerve
Teratoneuroma of the optic disc and optic nerve
Teratoid medulloepithelioma of the optic disc and optic nerve
Non-teratoid medulloepithelioma of the optic disc and optic nerve

Medulloepitheliomas of the optic disc and optic nerve are extremely rare primary intraocular embryonal tumors arising from the optic disc and optic nerve.

A medulloepithelioma of the optic disc and optic nerve may also be referred to as a diktyoma or teratoneuroma, although the use of these terms is not recommended ¹. They are included among the primary tumors of the optic disc and optic nerve in the last WHO classification of eye tumors. Despite being considered distinct entities from the medulloepitheliomas of the ciliary body, they share many histopathologic features with the latter.

Moreover, they should not be confused with medulloepitheliomas of the brain.

Epidemiology

Medulloepitheliomas of the optic disc and optic nerve are rarer than their analogous tumor arising from the ciliary body ². They usually occur around 2-3 years of age and are more common in males ³.

Pathology

Microscopic appearance

As medulloepitheliomas of the optic disc and optic nerve are analogous to the tumors of the ciliary body, they also show neuroepithelial cells similar to embryonic medullary epithelium organized into ribbons and cords. A net-like pattern of neuroepithelial cells (the so-called "diktyomatous pattern") may be seen ¹.

They are classified as teratoid or non-teratoid basing the presence/absence of cartilaginous, muscular, or brain tissue components. Malignant transformation is suspected in presence of Homer Wright or Flexner–Wintersteiner rosettes, brisk mitotic activity, atypia, sarcomatous changes, local and/or extraocular invasion with metastasis ¹.

Radiographic features

Because of their rarity, there are not many radiological descriptions in the literature. Their characteristics are not specific and are distinct from the medulloepitheliomas of the ciliary body. They appear as intraconal and well-defined masses (sometimes fusiform) centered on the optic nerve or optic disc ³.

CT

the teratoid medulloepitheliomas may show calcifications due to the presence of cartilage ⁴

MRI

T1: isointense or mildly hyperintense to vitreous
T2: hypointense to vitreous
T1 C+ (Gd): heterogeneous contrast-enhancement due to cystic changes, but may be homogeneous ⁴

Treatment and prognosis

Treatment typically consists of surgical resection. Prognosis is poor in patients with intracranial extension and metastasis, while it is usually better in the cases of intraocular tumors ³.