The term<unk> " was first coined by Leblanc, in 1831 following the removal of a lesion that resembled skin at the base of a horse's skull.<unk> s were first clearly described in 1885 by Bytlin. In 1891, Chairi was the first to propose that the tumors in the floor of the mouth originated from the entrapped epidermoid cells during the embryonic age.<unk> s may be classified according to the mode of occurrence into congenital and aquired types and into several subtypes based on the anatomical location.<unk>  arises from the entrapped embryonal ectodermal cells during the fetal development and are generally formed of skin, hair follicles, hair follicles, teeth and sebaceous glands. Acquired<unk> s may result from iatrogenic or traumatic implantation of the epithelial cells that subsequently grow. On gross pathology, uniloculated cysts lined by skin, containing sebaceous glands, hair follicles, and teeth are characteristic findings of<unk> s. On microscopic histopathological analysis, fibro collagenous cysts lined by stratified squamous epithelium, with epidermal appendages such as hair follicles, sweat and sebaceous glands are characteristic findings of<unk> s.<unk>  must be differentiated from teratoma, as well as other common benign tumors that develop in the head and neck, ovaries, or spine (such as pilar cysts, steatocystoma, pilomatrixoma, encephalocele, vascular malformations, lipoleiomyoma, pilonidal cyst, and lipoma).<unk> s are rare benign tumors. Spinal<unk> s commonly affect  individuals in their second or third decades of life. Males are more commonly affected with spinal<unk> s than females.<unk> s in other locations affect men and women equally. There is no racial predilection to the<unk> s. The majority of patients with<unk> s are asymptomatic. If left untreated,<unk> s gradually increase in size and produce symptoms depending upon their anatomical location. Depending on the anatomical location of the tumor, the prognosis may vary. The majority of patients with ovarian<unk> s are asymptomatic. They are discovered incidentally on routine physical exam or imaging for other reasons. Physical examination findings in patients with<unk>  may include a painless swelling that may be freely mobile or fixed to the skin and deeper structures. Congenital<unk> s localized to the scalp, neck or trunk are usually visible at birth. Xray, CT, MRI, and ultrasound are helpful in the diagnosis of<unk> s. Surgery is the mainstay of treatment for<unk> s.
Dermoid cyst
Epidermoid cyst
Nabothian cyst
Sebaceous cyst
Trichoblastoma
Cylindroma
Baker's cyst
Acrospiroma