Crocodile Shagreen

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 by Erica Bernfeld M.D. on February 21, 2020.


Crocodile Shagreen
Crocodile shargreen.
Crocodile shargreen. Reproduced, with permission, from Wang MX, Corneal Dystrophies and Degenerations: A Molecular Genetics Approach (Ophthalmology Monographs, 16), American Academy of Ophthalmology, 2003. [1]


Disease Entity

Originally described in 1927 by Weizenblatt and named by Vogt in 1930, crocodile shagreen is thought to be a benign, degenerative condition of the cornea which is usually asymptomatic.

Disease

Crocodile shagreen classically appears as bilateral, symmetric, polygonal opacities within the central posterior corneal stroma. The opacities have indistinct edges with intervening clear spaces. The pattern closely resembles “crocodile skin.”

Epidemiology/Risk Factors

It is most commonly associated with advanced age. It may be seen in association with band keratopathy or after traumatic corneal injury. Isolated cases have been reported in pseudoxanthoma elasticum, glaucoma, and polymorphic amyloid degeneration[2].

Etiology/Pathophysiology

It is most likely a degenerative disorder with a non-familial pattern of occurrence (in contrast to Central Cloudy Dystrophy of Francois).

Diagnosis

Histopathology

Electron microscopy has revealed the presence of vacuoles within the corneal stroma, which contain electron-dense material.[2] A sawtooth-like configuration of the collagenous lamellae which make up the corneal stroma is present, and this alteration of the collagenous lamellae may lead to the polygonal opacities observed clinically[2].

Differential Diagnosis

Central Cloudy Dystrophy of Francois, which has autosomal dominant transmission, has a similar clinical appearance. Similar anterior corneal findings have been described with fluorescein staining after pressure patching, ocular hypotony, flattening of keratoconic cornea by a hard contact lens, band keratopathy, and X-linked megalocornea.

Management/Treatment

This condition is not believed to cause reduced vision. No treatment is necessary.

Prognosis

The prognosis is usually very good as the condition is usually asymptomatic.

References

  1. American Academy of Ophthalmology. Crocodile shargreen. https://www.aao.org/image/crocodile-shargreen-2 Accessed July 30, 2019.
  2. 2.0 2.1 2.2 Belliveau, Brownstein, Agapitos, Font. Ultrastructural Features of Posterior Crocodile Shagreen of the Cornea. Survery of Ophthalmology 2009; 54 (5); 569-575.2. Tripathi RC and Bron AJ. British Journal of Ophthalmology 1975; 59; 59.
2. Krachmer, CORNEA, Second edition, 2005, Volume One, p 999.