A dermoid cyst is a teratoma of a cystic nature that contains an array of developmentally mature, solid tissues. It frequently consists of skin, hair follicles, and sweat glands, while other commonly found components include clumps of long hair, pockets of sebum, blood, fat, bone, nail, teeth, eyes, cartilage, and thyroid tissue. As dermoid cysts grow slowly and contain mature tissue, this type of cystic teratoma is nearly always benign. In those rare cases wherein the dermoid cyst is malignant, a squamous cell carcinoma usually develops in adults, while infants and children usually present with an endodermal sinus tumor. : 781

Location
Due to its classification, a dermoid cyst can occur wherever a teratoma can occur. Vaginal and ovarian dermoid cysts
Ovaries normally grow cyst-like structures called follicles each month. Once an egg is released from its follicle during ovulation, follicles typically deflate. Sometimes fluid accumulates inside the follicle, forming a simple (containing only fluid) cyst. The majority of these functional cysts resolve spontaneously.While all ovarian cysts can range in size from very small to quite large, dermoid cysts are not classified as functional cysts. Dermoid cysts originate from pluripotent germ cells (which are present at birth) that differentiate abnormally, developing characteristics of mature dermal cells. Complications exist, such as torsion (twisting), rupture, and infection, although their incidence is rare. Dermoid ovarian cysts which are larger present complications which might require removal by either laparoscopy or laparotomy (traditional surgery). Rarely, a dermoid cyst can develop in the vagina.
The condition does not typically lead to hydrocephalus, however, because there is no difference in pressure between various parts of the brain. However, those who have deep cerebral venous sinus thrombosis or oedema at basal ganglia are more prone to hydrocephalus development.Any blood clot forms due to an imbalance between coagulation (the formation of the insoluble blood protein fibrin) and fibrinolysis. The three major mechanisms for such an imbalance are enumerated in Virchows triad: alterations in normal blood flow, injury to the blood vessel wall, and alterations in the constitution of blood (hypercoagulability). Most cases of cerebral venous sinus thrombosis are due to hypercoagulability. The inflammatory response and prolonged immobilization of patients with COVID-19 may also help explain the formation of CVST.It is possible for the clot to break off and migrate (embolise) to the lungs, causing a pulmonary embolism. An analysis of earlier case reports concludes that this occurs in about 10% of cases, but has a very poor prognosis.Central venous thromboses usually involve the dural sinuses with or without involvement of the cortical veins; isolated cortical venous thromboses are extremely rare with only about 100 cases reported. Treatment
Various studies have investigated the use of anticoagulation to suppress blood clot formation in cerebral venous sinus thrombosis. Before these trials had been conducted, there had been a concern that small areas of hemorrhage in the brain would bleed further as a result of treatment; the studies showed that this concern was unfounded.