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Appropriate management of malignant lesions of the conjunctiva requires detailed knowledge of the appearance and nature of the lesions. Here's how to recognize and treat the most common malignant lesions seen by ophthalmologists.
The meeting was sponsored by Johns Hopkins University School of Medicine, Baltimore, and Ophthalmology Times.
According to Dr. Iliff, three malignant conjunctival lesions are of concern to ophthalmologists-melanoma, corneal and conjunctival intraepithelial neoplasia, and lymphoma-because they are the most common.
Pigmented conjunctival lesions should be monitored for growth, color change, or inflammation if they are very small. "If these lesions are anything more than the most modest bit of pigmentation, a biopsy should be performed or the lesion excised," said Dr. Iliff, professor of ophthalmology and plastic surgery, Wilmer Eye Institute, Johns Hopkins University. "With extensive lesions, biopsies should be performed in several places. More extensive lesions should not be followed."
Primary acquired melanosis (PAM) is a premalignant lesion. If biopsy demonstrates no atypia, it can be followed. Cellular atypia suggests melanoma in situ and should be treated.
PAM can appear anywhere on the conjunctiva and be golden or chocolate brown. "PAM is usually flat and moves with the conjunctiva, has indistinct edges, can be unifocal or multifocal, and does not have cysts," he explained.
In addition to excision, PAM can be treated with cryotherapy; a freeze-refreeze technique is used.
Mitomycin-C (Mutamycin, Bristol-Myers Squibb Oncology) is another possible therapy. "Mitomycin-C may be helpful in the treatment of PAM. Mitomycin-C is effective in eliminating the pigment, but we are not certain how effective it is in eliminating the disease, especially in the superior conjunctival fornix," Dr. Iliff said. "We have seen patients treated for PAM with mitomycin-C have dramatic reduction in evident pigmentation, only to go on to develop melanomas within a year of cessation of treatment."
If the physician opts for mitomycin-C, 0.4 mg/ml or 0.2 mg/ml drops are applied four times daily for 2 weeks or for 1 week on, 1 week off, and 1 week on. Any inflammation and punctate epithelial erosions are managed with prednisolone drops, erythromycin ointment, or lubricating ointments; punctal plugs can be used to limit systemic absorption and chance of damage to the lacrimal outflow system. The patient then is followed every 3 months, and another biopsy can be performed if evidence suggests disease progression or recurrence.
Conjunctival melanomas can arise from PAM or nevi, or de novo, according to Dr. Iliff. These lesions can be anywhere, may or may not be pigmented, may have cysts, and can be elevated or nodular. In addition, they are usually movable but also can be fixed if at the limbus or involving the tarsus. The lesions may be unifocal or multifocal and can be well-circumscribed or have indistinct edges.
"If a melanoma is suspected, it should be excised with an adequate margin of about 3 mm and double freeze-thaw cryotherapy applied surrounding the area. Any corneal involvement should be excised, and residual PAM of the cornea, if present, removed with absolute alcohol. Widespread PAM of the conjunctiva can be treated with mitomycin-C," Dr. Iliff said. "Metastases initially are to the preauricular, submandibular, or anterior cervical nodes. There may be some utility for sentinel node biopsy. Certainly, evidence of involvement of regional nodes would require investigation. A local node dissection may be necessary. Exenteration of the orbit may only be palliative because it is unknown if exenteration makes a difference in the long-term life expectancy of these patients."
The metastatic workup involves an initial workup including a history and physical examination by an internist.
In addition, Dr. Iliff also recommended computed tomography, magnetic resonance imaging, or positron emission tomography of the head, neck, chest, and abdomen.