Orbital ectopic glial tissue in relation to medial rectus: a rare entity

Abstract

Heterotopic brain tissue is a rare entity and it is rarer still in the orbit. There have been very few case reports of orbital ectopic glial tissue. The case is described herein of a 3-month-old baby presenting with an orbital glial hamartoma inseparable from the medial rectus muscle. The diagnosis was based on the histopathological features and a positive GFAP stain. The features of this case and the previously reported cases are discussed.

Glial Heterotopia or Ectopic Brain Masquerading as a Dacyrocystocele

“…4,5 Few cases has also been reported in orbit presenting as proptosis and strabismus. [6][7][8][9] The underlying cause for heterotopic or ectopic glial tissue has been theorized to be related to the abnormality in development of facial and skull bone plates but can also be seen isolated in the form of nodules without any connection to the central nervous system. 10 The isolated glial masses are believed to have originated from the misdirected or sequestered embryonic neuroectodermal stem cell rests.…”

“…9,10 CT scan features described for glial heterotopic masses in the orbits include well-circumscribed hypo-to isodense masses, minimal cystic areas, minimal rim enhancement with adjacent bony scalloping but without erosions. [6][7][8][9] There are no well-defined or characteristic MRI features. In contrast, both CT scan and MRI in dacryocystoceles shows fluid collection with a thin rim enhancement along the course of lacrimal sac and nasolacrimal ducts.…”

“…[1][2][3] Histopathological evaluation usually reveals fibrous and vascularized connective tissues with scattered mature glial tissue in a fibrillary background. [4][5][6][7][8][9][10] The cells are predominantly astrocytes with sparse or absent neurons, and this differentiates it with an encephalocele where abundant neurons will be noted. As the age of the patient increases, the fibrous component of glial heterotopic masses increases significantly with minimal glial tissues.…”

“…4 Treatment recommended for glial heterotopia is a complete excision of the mass even though there is no malignant or metastatic potential. [4][5][6][7][8][9] There is a controversy in the literature regarding the growth potential of these masses, but many believe that conservative management risks a possible continued growth with its attendant complications depending on the site. However, incomplete excisions are noted to have a recurrence rate of around 10%.…”

Glial heterotopia in an adult: A rare orbital mass

“…Some authors opine that this could be dysembryogenic in origin, and some opine that it could have got admixed with the developing muscle. [46]…”