Eyelash trichomegaly complicating pembrolizumab for colorectal cancer

A 63-year-old male patient developed eyelash trichomegaly after two cycles of pembrolizumab, an immune checkpoint inhibitor used for treating colorectal cancer. Despite the discomfort caused by the eyelash condition, the patient continued the treatment due to a complete radiologic response of his cancer. This case highlights the rare occurrence of pembrolizumab-induced eyelash trichomegaly and underscores the importance for clinicians to be aware of such uncommon side effects for effective patient management.