Cutaneous cyst Trichilemmal cyst 2016-12-17T13:45:04Z Pilar cyst Nontender, round and firm, but slightly compressible, intradermal or subcutaneous cyst measuring 0.5-5 cm in diameter. Trichilemmal cysts are acquired rather than congenital, and tend to appear on the scalp rather than the face, and to be intradermal rather than subcutaneous. Epidermal cysts and trichilemmal cysts are clinically indistinguishable. The wall of the epidermal cyst conserves the epidermal layers, but the wall of the trichilemmal cysts, which arise from the external root sheath, shows palisading of unlayered epithelial cells. Homogeneous horny material that is further degraded to fat and cholesterol forms within both types of cysts.