A Rare Transformation of Epidermoid Cyst into Squamous Cell Carcinoma: A Case Report with Literature Review.

BACKGROUND Epidermoid cysts are the most common benign skin lesions that can occur anywhere on the body, and frequently occur on the face, scalp, neck, and trunk. Typically, patients are asymptomatic, and the lesions present as firm skin-colored nodules filled with keratinous or sebaceous materials that are formed by cystic expansion of the epidermal epithelium. Malignant transformation is rare in epidermoid cysts.