Keratoacanthoma of the Conjunctiva: A Diagnosis to Keep your Eye out For

Summary: A 28-year-old female, with no past medical history, presented with a white conjunctival papule that had rapidly grown over one week. At initial presentation, it was favored to be a conjunctival cyst, although it did not transilluminate and felt indurated. After three weeks of treatment with neomycin, polmyxin B, and dexamethasone eye drops, the lesion continued to grow and a biopsy was performed. Pathology revealed a crateriform papule filled with keratin with squamous atypia. This was consistent with a well-differentiated squamous cell carcinoma with features of a keratoacanthoma of the conjunctiva. The patient is currently being treated with 5-fluorouracil eye drops. Keratoacanthomas are common cutaneous neoplasms, which many believe to be a variant of squamous cell carcinoma. However, conjunctival keratoacanthomas are very rare with few previously reported cases. It typically presents clinically as a rapidly growing white papule or nodule. While conjunctival keratoacanthomas may develop in older patients, there have also been reports in young, healthy patients, as in this case. Histopathology demonstrates well-differentiated squamous cell carcinoma with a crateriform architecture with cells often displaying a glassy cytoplasm. Treatment is with excision although spontaneous resolution may occur. It is important to be aware of this entity to avoid misdiagnosis.