Metastatic Squamous Cell Epiretinal Membrane Diagnosed with Surgical Biopsy.

Purpose: To describe an exceedingly rare presentation of vitreoretinal involvement of metastatic tonsillar squamous cell carcinoma and illustrate the utility of therapeutic and diagnostic epiretinal membrane biopsy.

Methods: Case report.

Results: A 57-year-old male presented with new vitreous opacities in the left eye. He had a history of tonsillar squamous cell carcinoma status-post surgical excision and currently undergoing chemotherapy and radiation therapy. The patient underwent vitreous biopsy which revealed scant cellularity with concern for squamous neoplasia. Soon after, the patient developed a rapidly progressive epiretinal membrane. Membrane peel surgery with en-bloc removal of the epiretinal membrane was performed. Hematoxylin and eosin stain of the sample revealed multiple squamous eddies and mitotic figures, and cytokeratin AE1/AE3 marker was strongly positive, confirming the diagnosis of metastatic squamous cell carcinoma. Intravitreal melphalan injections were started in the left eye. The patient achieved anatomic and visual improvement.

Conclusion: Intraocular squamous cell metastasis is rare, and diagnosis can be challenging. Despite initial inconclusive vitreous biopsy cytology in this case, an epiretinal membrane en-bloc sample was obtained, which confirmed involvement by the squamous cell carcinoma and prompted appropriate treatment.