Relative incidence of cutaneous cysts:<unk>  is labeled near top. A<unk>  is a common cyst that forms from a hair follicle, most often on the scalp, and is smooth, mobile, and filled with keratin, a protein component found in hair, nails, skin, and horns.<unk> s are clinically and histologically distinct from trichilemmal horns, hard tissue that is much rarer and not limited to the scalp. Rarely, these cysts may grow more extensively and form rapidly multiplying trichilemmal tumors, also called proliferating<unk> s, which are benign, but may grow aggressively at the cyst site. Very rarely,<unk> s can become cancerous.
Trichilemmal cyst
Trichodiscoma
Trichilemmoma
Proliferating trichilemmal cyst
Trichilemmal carcinoma
Nabothian cyst
Trichofolliculoma
Hidradenoma