Conjunctival Biopsy - Nevi, Primary Acquired Melanosis, and Melanoma

The Clinical Evaluation - Practical Tips!

• Conjunctival nevi usually do not cross over onto the cornea and do not involve the palpebral conjunctiva (the conjunctiva lining the inner surface of the eyelid).

Although small cysts are typical of compound conjunctival nevi, they may also be seen in primary acquired melanosis which arises in conjunction with nevi.

• Nevi in older children and adolescents may appear to grow. The "growth" may actually reflect an accumulation of an inflammatory response in and around the nevus. These so-called inflamed nevi of puberty are not associated with systemic pigmentary disorders such as halo nevi or vitiligo.
• All areas of pigmented conjunctival elevations should be biopsied. Melanoma should not be treated primarily with cryotherapy or mitomycin C topical chemotherapy.

Surgical Approach - In General

• These lesions often cross the limbus onto the cornea. When they do involve the cornea, they usually involve only the corneal epithelium.
• Do not perform lamellar dissections into the cornea to remove lesions that straddle the limbus. Bowman's layer is a natural barrier to the penetration of malignancies into the stroma and if the lesion recurs after Bowman's layer has been violated surgically, the recurrent lesion has unimpeded access to the stroma.

Surgical Approach - Specific Steps

• Balloon up the affected conjunctiva with anesthetic. If the lesion separates from the episclera after the injection, it is unlikely that the lesion has invaded the episclera.
• Dissect the lesion up to the limbus but do not dissect into the corneal stroma.
• Prepare the conjunctival biopsy for the pathologist, taking care to keep the specimen flat. Remember to tag margins appropriately. Click here to obtain hints on handling conjunctival biopsy specimens.
• If the corneal epithelium is involved, instill topical anesthesia. Then, moisten a cotton-tip applicator with absolute alcohol and gently wipe the diseased epithelium off. You may place the glob of epithelium onto a piece of filter paper and submit it for pathologic examination.ference:

Spencer WH, Folberg R: Conjunctiva. In Spencer WH (ed): Ophthalmic Pathology - An Atlas and Textbook, 4th edition, Philadelphia, WB Saunders, 1996. pp. 125-155.

Primary acquired melanosis with atypia, basilar hyperplasia pattern. Atypical melanocytes are distributed primarily along the basal layer of the epithelium in this pterygium. If untreated, 50% of lesions with this histology may progress to conjunctival melanoma.The best treatment for conjunctival melanoma is detection and treatment of precursor lesions.