Superficial Corneal Growth FREE

During a routine office visit, you notice that your patient, a 70-year-old white man, has a small superficial growth on the surface of his right eye that you do not remember seeing before (Figure 1). When you ask about it, your patient tells you he has had the lump for about a month. He has had no previous ophthalmic or relevant medical history. He also denies any prior surgery, trauma, or infection. Physical examination is remarkable only for a superficial right corneal lesion.

A . Ask the patient to stop rubbing his eyes so frequently
B . Do nothing today, follow up in 3 months
C . Refer to ophthalmologist for biopsy of the lesion
D. Refer to ophthalmologist for corneal transplant

Primary corneal myxoma

C. Refer to ophthalmologist for biopsy of the lesion

The key clinical feature in this case is knowing the differential diagnosis for a benign-appearing corneal lesion. The differential diagnosis of corneal myxoma includes Salzmann nodular degeneration, allergic hypertrophia, corneal keloid, amyloid deposition, corneal squamous cell carcinoma, and acute hydrops in keratoconus. Distinguishing among these conditions would require biopsy of the lesion, which is the preferred course of action in this case.

A myxoma is a benign tumor of primitive connective tissue found most frequently in the left atrium of the heart. In the eyes, myxoma has been described in the lids, orbit, and conjunctiva.² Corneal myxomas tend to form anteriorly beneath the epithelium and arise in previously inflamed or injured corneas.² Because it is a secondary reactive process in a person who has had prior corneal disease or injury, a primary lesion in the cornea is considered rare. The common pathogenetic feature of all cases is chronic corneal edema.³

Elevated mass lesions of the cornea are relatively rare and can be difficult to diagnose clinically because there is a wide differential diagnosis. However, each entity has unique histologic features. Myxomas are usually nonencapsulated and consist of widely separated stellate and spindle-shaped mesenchymal cells (modified fibroblasts) sparsely distributed in a loose myxoid stroma. This stroma, a basophilic myxoid background rich in hyaluronic acid, resembles loose, mucoid tissue in the umbilical cord.³ The precise origin of myxomas is unknown, but possibly they are derived from abnormal mesenchymal cells (fibroblasts) that, instead of producing mature collagen fibers, secrete excess mucopolysaccharides.^2,4

Biopsy of the lesion is shown in Figure 2. The lesion consisted of spindle-shaped cells within a loose myxoid stroma (hematoxylin-eosin and periodic acid–Schiff). The spindle cells were negative for smooth muscle actin (periodic acid–Schiff) and amyloid (Congo red). Alcian blue staining the matrix reacted positively prior to hyaluronidase treatment, showing hyaluronidase-sensitive acid mucopolysaccharides. Stain for vimentin, an intermediate filament found in mesenchymal cells, was positive, characteristic of myxomas.

Salzmann nodular degeneration, a nonspecific hypertrophic reactive process, is a late sequela of corneal inflammatory disease. Histology shows fusiform plaques of hyalinized collagen and epithelian basement membrane material and subepithelial nodular thickening. It is positive for Congo red stain. Treatment includes keratectomy.⁵ Histology of primary nodular fasciitis lesions shows capillary-sized blood vessels, chronic inflammatory cells, feathery architecture, and extravasated erythrocytes. It is often associated with chronic eye rubbing.⁶ Histology of acute keratoconus shows epithelial and stromal edema breaks in the Bowman layer and Descemet membrane, which are not seen in myxoma. It is treated by surgical removal of central nodular scars, contact lenses, and in severe cases, corneal transplant.⁷ Treatment for myxoma is local excision. Although myxoma of the orbit tends to recur, conjunctival myxoma has a low incidence of recurrence.⁸