Development of Conjunctival Squamous Cell Carcinoma During Systemic Pembrolizumab Therapy for Laryngeal Cancer: A Case Report and Literature Review

Advanced conjunctival squamous cell carcinoma (SCC) can be difficult to treat and may require orbital exenteration—a disfiguring and often psychologically distressing procedure. Recently, immune checkpoint inhibitors, such as cemiplimab and pembrolizumab, have shown promise as alternatives for advanced disease, with an early case series reporting encouraging outcomes. Herein, we describe a rare case of primary conjunctival SCC arising during ongoing pembrolizumab therapy for an unrelated malignancy. This unexpected development highlights the variability in tumor responsiveness to immune checkpoint inhibitors and the underlying biological heterogeneity of conjunctival SCC. This case, along with emerging literature, underscores the importance of a more individualized approach to immunotherapy in ocular surface malignancies. It also reinforces the need for reliable predictive biomarkers to guide treatment selection and improve outcomes in conjunctival SCC.