Dermoid cysts (DCs) are unusual benign congenital intracranial tumors that typically arise in the midline and form as a result of abnormal sequestration of ectodermal cells during neural tube formation.
These uni or multilocular cystic tumors lined by squamous epithelium containing skin appendages (hair follicles, sweat glands, sebaceous glands) are congenital in origin.
In about 66%, the dermoid cysts are associated with some form of dermal sinus 1).
They are considered benign, and in all reported cases the cysts were well encapsulated on surgical removal. However, a case of squamous cell carcinoma dedifferentiation has been reported, and a few cases of rupture of the cyst leading to aseptic meningitis have been described 2) 3).
The intracranial dermoid cyst (ICD) can be complicated by rupture and spilling of its contents with potentially dreadful consequences. Head trauma as a predisposing element for this phenomenon is extremely rare. Few reports address the diagnosis and management of trauma-related rupture of ICD. However, there is a pronounced knowledge gap related to the long-term follow-up and the fate of the leaking contents 4).
The association between a dermoid cyst and arachnoid cyst is extremely rare and when it is present may suggest the existence of a common factor. Abbou et al. presented a unique case of a young girl who developed headache and ataxia as a result of an intracranial infratentorial dermoid cyst and an arachnoid cyst of the cerebellopontine angle. Complete removal of the dermoid cyst and drainage of the cyst leads to a full recovery. Dermoid and arachnoid cyst are two pathologies with a possible common embryogenic factor, early surgery can give a better outcome in the long term 5).
Dermoids are not unique to a single anatomic location but are often isolated to the skin and subcutaneous tissue.
They may occur intracranially or intra-abdominally, oftentimes associated with the ovary.
The intracranial lesions are commonly located in the posterior fossa.
see Cranial dermoid cyst.
Dermoid cysts are slowly growing benign lesions of ectodermal tissue that often occur in the anterior fontanelle. Clinicians often rely on a negative transillumination test to begin the process of correctly diagnosing a dermoid cyst. Shastri et al. present a case of a 7-month-old girl who presents with a transilluminating dermoid cyst 6)
In contrast to more common nasal and cervical lesions, the frontotemporal pit is a rarely encountered lesion that is often associated with a dermoid and may track intracranially. Due to delays in diagnosis, the propensity to spread intracranially, and the risk of infection, awareness of these lesions and appropriate diagnosis and management are important. Bliss et al., present 2 cases of frontotemporal pits from a single institution. Epidemiology, presentation, and management recommendations are discussed 7).
A 14-year-old girl had an ICD rupture following a vehicle collision. The cyst was located near the foramen ovale with intra and extradural extensions. Initially, we opted to follow the patient clinically and radiologically as she had no symptoms, and the imaging showed no red flags. Over the next 24 months, the patient remained asymptomatic. However, the sequential brain magnetic resonance imaging revealed significant continuous migration of the fat within the subarachnoid space, with the droplets noticed to increase in the third ventricle. That is considered an alarming sign of potentially serious complications impacting the patient's outcome. Based on the above, the ICD was completely resected through an uncomplicated microsurgical procedure. On follow-up, the patient is well, with no new radiological findings.
Trauma-related ruptured ICD may have critical consequences. Persistent migration of dermoid fat can be managed with surgical evacuation as a viable option to prevent those potential complications such as obstructive hydrocephalus, seizures, and meningitis 8).