All of the following names are interchangeable except which?

• A. Conjunctival cyst
• B. Milia
• C. Inclusion cyst
• D. Retention cyst

Answer: (B)

All of these terms refer to cystic lesions related to the conjunctiva, describing how the cyst forms or where it sits on the conjunctival surface. A conjunctival cyst can be labeled as an inclusion cyst when it results from trapped conjunctival epithelium, or as a retention cyst when it forms from blocked ducts that accumulate mucous. These terms are essentially describing the same type of lesion from different mechanistic angles. Milia, however, are a different entity: tiny keratin-filled epidermal inclusion cysts that occur on the eyelid skin, not on the conjunctival surface. Because milia are not true conjunctival cysts, they are not interchangeable with the terms used for conjunctival cysts.