What long can inclusion cysts last?

Epidermoid Cysts. Epidermoid cysts are usually asymptomatic; however, they may become inflamed or secondarily infected, resulting in swelling and tenderness. Rarely, malignancies, including basal cell carcinoma, bowen disease, scc (most common of these rarities), mycosis fungoides, and melanoma in situ, have developed in epidermoid cysts.