====== Dermoid cyst ====== {{rss>https://pubmed.ncbi.nlm.nih.gov/rss/search/10YYOHVqhl3iE00dqD3Uzec9xuPrF8JYplh4WwJ3R7qWSSS9ap/?limit=15&utm_campaign=pubmed-2&fc=20230321033714}} ---- ===== Definition ===== [[Dermoid]] [[cyst]]s (DCs) are unusual benign congenital [[intracranial tumor]]s that typically arise in the midline and form as a result of abnormal sequestration of [[ectoderm]]al cells during [[neural tube]] formation. ===== Pathology ===== 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]] ((Caldarelli M, Massimi L, Kondageski C, Di Rocco C. Intracranial midline dermoid and epidermoid cysts in children. J Neurosurg. 2004;100(5 Suppl Pediatrics):473–80.)). ===== Outcome ===== 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 ((OertelJ,PiekJ,Mu ̈llerJU,etal.Posteriorfossasquamouscellcarcinomadue to dedifferentiation of a dermoid cyst in Klippel-Feil syndrome case illustration. J Neurosurg 2002;97:1244)) ((AksoyFG,AksoyOG,GomoriJM.Klippel-Feilsyndromeinassociationwith posterior fossa suboccipital dermoid cyst. Eur Radiol 2001;11:142– 44)). ---- 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 ((Aktham A, Morita S, Takeuchi S, Ismail M, Hoz SS, Numazawa S, Watanabe S, Mori K. Traumatic rupture of intracranial dermoid cyst with continuous fat droplet migration. Surg Neurol Int. 2023 Feb 3;14:39. doi: 10.25259/SNI_801_2022. PMID: 36895256; PMCID: PMC9990783.)). ===== Associations ===== 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 ((Abbou Z, Djennati R, Khalil Z. A rare association between a dermoid cyst and arachnoid cyst of the cerebellopontine angle: a case report. Pan Afr Med J. 2021 Nov 1;40:125. doi: 10.11604/pamj.2021.40.125.32040. PMID: 34909093; PMCID: PMC8641637.)). ===== Localization ===== 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]]. see [[Spinal dermoid cyst]] see [[Nasofrontal dermoid cyst]] see [[Orbital dermoid cyst]] see [[Intracranial dermoid cyst]]. ===== Diagnosis ===== [[Dermoid cyst]]s are slowly growing benign lesions of [[ectoderm]]al [[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 ((Shastri D, Fisher WAM, Wood J, Quinsey C. Transillumination of an Anterior Fontanelle Dermoid Cyst. J Craniofac Surg. 2023 Mar 21. doi: 10.1097/SCS.0000000000009253. Epub ahead of print. PMID: 36941237.)) ---- 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 ((Bliss M, Grant G, Tittler E, Loven T, Yeom KW, Sidell D. Diagnosis and treatment of pediatric frontotemporal pits: report of 2 cases. J Neurosurg Pediatr. 2016 Oct;18(4):471-474. PubMed PMID: 27391653.)). ===== Case reports ===== 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 ((Aktham A, Morita S, Takeuchi S, Ismail M, Hoz SS, Numazawa S, Watanabe S, Mori K. Traumatic rupture of intracranial dermoid cyst with continuous fat droplet migration. Surg Neurol Int. 2023 Feb 3;14:39. doi: 10.25259/SNI_801_2022. PMID: 36895256; PMCID: PMC9990783.)).