This article was reviewed by Bita Esmaeli, MD, FACS
Clinical recognition of salmon patch infiltrate requires the consideration of a number of factors, and it is the first important step in diagnosing and managing conjunctival lymphoproliferative lesions including marginal zone B-cell lymphoma.
Ophthalmologists should be familiar with the clinical appearance which is usually that of a “salmon patch” infiltrate and can affect any part of the ocular surface including the tarsal and palpebral conjunctiva.
This pathology is not limited to one area; the entire ocular surface must be inspected, according to Bita Esmaeli, MD, FACS, professor and director of the Ophthalmic Plastic and Orbit Program, at MD Anderson Cancer Center, Houston.
Eversion of the upper eyelid is important for identifying the full extent of conjunctival lymphomas. Some lesions, she explained, can be very small and limited to the caruncle or a small follicular infiltrate.
Symptoms can include chronic discharge, itchiness, conjunctivitis, and allergic reaction. In some cases, the lesions can be asymptomatic and discovered only coincidentally during the evaluation of other clinical processes.
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Biopsy is key
Reactive lymphoid hyperplasia can have an appearance that is similar to lymphoma, indicating that biopsy is a key diagnostic step in ferreting out benign and malignant lesions, Dr. Esmaeli pointed out.
“Biopsy is required to establish the diagnosis of lymphoma and the exact histologic subtype,” she said.
Pathologists often rely on standard morphology, immunohistochemistry, and hematoxylin and eosin staining in cases with conjunctival lesions because the tumor burden may be too small to facilitate flow cytometry, the gold standard for more definitive diagnosis of lymphoma, she pointed out.
Surgeons should also bear in mind that evidence of a lesion on the conjunctiva may be the proverbial tip of the iceberg, that is, the disease can extend well into the orbit.
“For conjunctival lymphoma, the histology is usually very low grade, and more than 90% are likely mucosa-associated lymphoid tissue (MALT) lymphomas,” Dr. Esmaeli said. “Other more aggressive histologic subtypes of lymphoma also can rarely occur, and in most cases they would have an extension into the orbit.”
At this stage, an important goal is ruling out systemic lymphoma. Positron emission tomography-computed tomography are useful, as are bone marrow biopsy, which are performed at most cancer centers—and even “stage 4” conjunctival MALT lymphoma is possible to be found at initial diagnosis of conjunctival MALT lymphoma with a positive bone marrow involvement.
“That does not necessarily mean that patients need aggressive treatment, but it could be a clue that such patients with a positive bone marrow biopsy will relapse in the future at extraocular sites,” she said.