Posttraumatic Giant Extradural Intradiploic Epidermoid Cysts of Posterior Cranial Fossa : Case Report and Review of the Literature

We reported a unique case of posttraumatic giant infratentorial extradural intradiploic epidermoid cyst. A 54-year-old male, with a previous history of an open scalp injury and underlying linear skull fracture in the left occipital region in childhood, presented with a painful subcutaneous swelling, which had been developed gradually in the same region and moderate headache, nausea, vomiting and cerebellar ataxia. The duration of symptoms on admission was 3 months. Imaging studies revealed occipital bone destruction and giant extradural intradiploic lesion. The preoperative diagnosis was giant infratentorial extradural intradiploic epidermoid cyst. Surgery achieved total removal of the lesion, which was histologically confirmed and the postoperative course was uneventful. To our knowledge, this is the first case of giant infratentorial extradural intradiploic epidermoid cyst with a traumatic etiology described in the literature.     

Giant intradiploic epidermoid cyst of the occipital bone

Epidermoid cysts are uncommon, benign and slow-growing lesions. They often reach an enormous size without producing neurologic symptoms. We describe a 35-year-old female who had a giant intradiploic epidermoid cyst of the occipital bone. She underwent posterior cranial fossa tumor resection. Pathology confirmed epidermoid cyst. There was no recurrence at 13-month follow-up. Total removal of these cysts and repeated washing of the cavity with 0.9% saline may prevent recurrence and aseptic meningitis.     

Giant intradiploic epidermoid cyst of the occipital bone

A rare case of giant intradiploic epidermoid cyst of the occipital bone with large intracranial extension in the posterior fossa is described. The lesion was discovered when the patient presented with headache and subcutaneous swelling in the occipital region, in the absence of signs of neurological involvement. CT scan showed extensive destruction of the occipital bone, mainly of the inner table, up to the foramen magnum. On MRI the lesion was hypointense in T(1) and hyperintense in T(2)-weighted images; signal inhomogeneity was due to cellular debris and cholesterol crystals. The enhancing rim due to the thickened dura confirmed the extradural location. Complete removal of the cyst was easily accomplished despite its large size. We found only 3 documented cases in the literature of giant intradiploic infratentorial epidermoid cysts, none of which was studied by MRI. The radiological features and differential diagnosis are discussed.     

Late appearance of hydrocephalus associated with posttraumatic intradiploic arachnoid cyst

Case report We present a case of a posttraumatic intradiploic arachnoid cyst associated with hydrocephalus in a 16-year-old boy. The diagnosis was missed 2 years previously, when an MRI following a transient gait disturbance failed to show the intradiploic extension of the cyst. He presented to us with hydrocephalus and a CT scan clearly identified the intradiploic position of the cyst.Outcome A fenestration between the lateral ventricle and the cyst with aqueductoplasty and ETV were performed with good results.     

Giant intramedullary epidermoid extending from the brain stem to the upper thoracic spinal cord

Epidermoid cysts are benign tumors originating from ectoderm remnants. Most epidermoid cyst cases are intracranial. Spinal epidermoid cysts are uncommon and most of the reported cases are in the thoracic and lumbar spine. Occurrence of intramedullary epidermoid cysts in the cervical spine is extremely rare. An 18-year-old male with a giant intramedullary tumor extending from the brain stem to the upper thoracic spinal cord presented at our outpatient department. The patient underwent total excision of a silvery white lesion through a midline myelotomy. Histopathological examination was suggestive of an epidermoid cyst. We present a brief report of the case and discuss the relevant literature.     

A giant intradiploic epidermoid cyst with perforation of the dura and brain parenchymal involvement

A patient with a long-standing intradiploic epidermoid cyst with perforation of the dura and brain parenchymal involvement is reported. A 69-year-old man, who had previously presented with a subcutaneous mass on the left frontoparietal scalp, developed a sudden grand mal seizure. Magnetic resonance imaging showed a well-defined mass in the frontoparietal scalp with destruction of the skull. Penetration of the dura allowed for communication with the intracranial structures. Surgical resection and cranioplasty were performed. There were no well-defined margins in the deep portion and the mass was subtotally removed. Histological examination showed that the cystic structure was lined by squamous epithelium containing laminated keratin material. The pathologic findings were consistent with the diagnosis of an epidermoid cyst.     

Ectopic ventricular recurrence of an epidermoid cyst in the middle fossa.

We present the first case of ectopic ventricular recurrence of an epidermoid cyst in the middle fossa with confirming histological characteristics. A 51-year-old woman presented with an epidermoid cyst in the middle fossa and underwent complete resection. On the 6-month surgical follow-up MRI, a nodular lesion was detected in the frontal horn of the left lateral ventricle without evidence of recurrence at the primary site. The patient underwent transcortial tumor resection. Results of histological studies confirmed that the lesion was an epidermoid cyst similar to the primary lesion. This is a case report of the cerebrospinal fluid spread of an epidermoid cyst, which strengthens the case for special care at the time of surgery to prevent spread of the lesion.     

Meningitis Complicating an Occult Infected Nasal Epidermoid Cyst in a Child

Congenital nasal epidermoid cyst without associated facial dysmorphism is an uncommon anomaly that is often asymptomatic. We report a case of occult nasal epidermoid cyst in a 12-year-old boy with initial nonspecific symptoms of fever, headache, abdominal pain, vomiting, and diarrhea. An enhanced magnetic resonance imaging (MRI) showed a cystic lesion in the frontal skull base with expansion of the foramen cecum and the perpendicular plate of the ethmoid bone, accompanied with meningitis. An emergent surgical intervention was undertaken, and an infected epidermoid cyst was confirmed by pathology. He recovered uneventfully during a 4-week treatment with parentally-administered antibiotics. This significant case report demonstrates the importance of MRI in the early diagnosis of a life-threatening intracranial infection from an otherwise occult infected congenital nasal epidermoid cyst in children.     

Basilar artery dissection: A rare complication of posterior fossa epidermoid cyst resection,and evaluation of the possible effects of cerebrospinal fluid drainage on disease progression

We report a rare case of a 45-year-old female with an unruptured basilar artery dissecting aneurysm presenting with locked-in syndrome due to brainstem ischemia eleven months following resection of a giant cerebellopontine angle epidermoid cyst and three months after insertion of ventriculo peritoneal shunt due to hydrocephalus. The etiology of basilar artery dissection and the effect of hydrocephalus and ventricular cerebrospinal fluid drainage on disease progression in this patient are unclear. Our report suggests a possible effect of hydrocephalus and ventricular cerebrospinal fluid drainage on intracranial arterial dissection progression.     

Giant epidermoid cyst of the skull with extra and intracranial extension. A case report

Intradiploic epidermoid cyst of the skull is a rare clinical entity that can exceptionally grow to a large size with intracranial extension. The authors report the case of a 38-year-old man with a giant epidermoid cyst of the parietal bone with extra and intracranial extension, presenting with focal neurological symptoms. The diagnosis was suggested at imaging (skull radiographs, CT and MRI), and confirmed at histology. Complete removal of the cyst and its capsule was performed followed by cranioplasty. Postoperatively, the patient was discharged free of symptoms. CT scan provides good evaluation of the bony lesion and may suggest intracranial extension. MRI is superior for evaluation of cerebral compression. The pathogenesis, clinical presentation, diagnostic evaluation and therapeutic management of these rare lesions are reviewed.     

Cavernous sinus dermoid cyst with unusual parapharyngeal development

We report a case of dermoid cyst arising in the cavernous sinus and parapharyngium areas through the foramen lacerum. A 12-year-old girl was hospitalized in October 1966 for progressive intracranial hypertension. CT before a prior surgical intervention in 1994 showed an intracranial process suggesting a dermoid cyst. CT performed in October 1996 showed a temporal process at the left side measuring 8 cm x 5 cm and well circumscribed with a thin wall. This process extended towards the parapharyngium area through the foramen lacerum. The exocranial part measured 4 cm in diameter. The density of the process strongly suggested a mature dermoid cyst with fatty and calcium components. The histology study confirmed the diagnosis of dermoid cyst. The frequency of intracranial dermoid cysts is 2 to 3 times less than that of epidermoid cysts. This is an uncommon process accounting for 1% of intracranial tumors occurring in children. In the sustentorial spaces, the process occurs more frequently in the parasellar area. To our knowledge, exocranial extension has not been reported to date.     

Post-traumatic intradiploic leptomeningeal cyst of the posterior fossa in an adult

Intradiploic cysts in the posterior fossa are rare. We report a post-traumatic intradiploic leptomeningeal cyst in an adult and review the diagnosis and pathogenesis of this lesion.A 28-year-old woman presented with a headache and a hard mass in the occipital region. She had a history of head injury as she had fallen from a height at the age of 18 months. CT scans and MRI revealed an expanding intradiploic cyst with the density of cerebrospinal fluid (CSF) and thinning of the inner and outer tables. A bony defect of the inner table connecting to the cisterna magna was also visualized. At surgery, we detected free communication of the CSF between the cystic cavity and the subarachnoid space of the posterior fossa via a defect in the dura and inner table. The dural defect was sutured primarily and covered with the autogenous outer table.An intradiploic cyst of the occipital bone can be detected in adults and might be caused by remote head injuries during childhood. Prompt surgical repair of the dural and bony defect in an adult patient has an excellent prognosis.     

Fulminant leptomeningeal carcinomatosis from a malignant melanoma arising in a cerebellopontine epidermoid cyst: A rare case with diagnostic pointers

A malignant component in an epidermoid cyst is rare. We report an exceptionally rare case of a malignant melanoma arising in an epidermoid cyst located in the cerebellopontine (CP) angle. A 26‐year‐old woman presented with headache, vomiting, ataxia and difficulty in swallowing over the previous 3 months. The radiological finding suggested an epidermoid cyst and the lesion was excised. The histopathology confirmed a CP angle epidermoid cyst. Within 1 month of discharge, she developed hydrocephalus for which a ventriculo‐peritoneal shunt was performed. Postoperatively she developed weakness in lower limbs. A contrast‐enhanced MRI was done which showed dilated CSF cisternal spaces with a small enhancing lesion in the pineal region and enhancement of meninges extending to the spinal cord. Re‐exploration showed gelatinous material with gross adhesions in the CP angle cistern. A dural biopsy was done which showed sheets of poorly differentiated tumor cells which expressed S100 and Melan A and were immunoreactive with Human Melanoma Black (HMB)‐45 antibody, consistent with the diagnosis of malignant melanoma. Histology of the excised epidermoid cyst was re‐evaluated in deeper sections and showed scattered atypical melanocytes in the basal layer of the epidermis which were highlighted with HMB‐45 antibody. The patient expired within 3 days of the second procedure due to respiratory failure. A very aggressive fulminant course of the disease was evident after surgery for the epidermoid cyst. Treatment options are limited. Criteria for identification of malignancy in an intracranial epidermoid cyst were identified in our case retrospectively and have been highlighted.     

Hemorrhagic epidermoid cyst in a patient with generalized tonic clonic seizure

Epidermoid cysts account for approximately 1% of all intracranial tumors. Hemorrhage into an epidermoid cyst is extremely rare, and has only been reported a few times. To our knowledge, there are no reports of a hemorrhagic epidermoid cyst presenting with a first generalized tonic clonic seizure. We present a 68-year old female with an epidermoid cyst with intracystic hemorrhage who presented with a first time generalized tonic clonic seizure. When complicated with hemorrhage, the diagnosis of an epidermoid cyst is challenging and there is a potential for misdiagnosis.     

Coexistence of a cerebellopontine epidermoid cyst with a pituitary adenoma

We report on an 18-year-old girl with the coexistence of an epidermoid cyst in the cerebellopontine angle (CPA) with a pituitary adenoma. The clinical course and histopathological characteristics were reviewed. The patient presented with headache, vision loss and amenorea. Computerised tomographic (CT) scan and magnetic resonance imaging (MRI) examinations demonstrated a solid sellar lesion with supra-sellar extension. There was another mass lesion in the CPA with prepontine extension. The tumours were removed surgically. Histopathological examination revealed an epidermoid cyst in the prepontine area and a pituitary adenoma in the sellar region. This has been the second case to be reported in the literature with the coexistence of an epidermoid cyst and a pituitary adenoma.     

Primary Intracranial Squamous Cell Carcinoma in the Brain Stem with a Cerebellopontine Angle Epidermoid Cyst

Primary intracranial squamous cell carcinoma is extremely rare, with most cases arising from a preexisting benign epidermoid cyst. We report a rare case of primary intracranial squamous cell carcinoma in the brain stem with a cerebellopontine angle (CPA) epidermoid cyst. A 72-year-old female suffered from progressive left hemiparesis, difficulty in swallowing, and right hemifacial numbness. Diffusion-weighted magnetic resonance imaging revealed a high signal intensity (SI) lesion in the CPA region and an intra-axially ring-enhanced cystic mass in the right brain stem with low SI. Whole-body positron emission tomography showed no evidence of metastatic disease. The histological findings revealed a typical epidermoid cyst in the CPA region and a squamous cell carcinoma in the brain stem. We speculate that the squamous cell carcinoma may have been developed due to a chronic inflammatory response by the adjacent epidermoid cyst. The patient underwent a surgical resection and radiotherapy. After 12 months, she had no evidence of recurrence.     

Intracranial germinoma in the pineal region arising after subtotal resection of epidermoid cyst: case report

We present an unusual case of a germinoma of the pineal region arising adjacent to an epidermoid cyst in a 16-year-old male. Initial imaging findings were classic for epidermoid cyst. The patient underwent two partial resections at an outside institution, each specimen demonstrating pure epidermoid cyst. Follow-up imaging over a period of 24 months showed an area of progressive contrast enhancement adjacent to the initial lesion, suggesting the development of a neoplasm. Given the area of contrast enhancement in addition to worsening headaches and visual changes, he underwent a third and final resection at our institution. Pathology revealed a mixed germ cell tumor with prominent germinoma component in addition to a well-differentiated epidermoid cyst. Details of his imaging and pathologic findings are presented, and possible explanations for these findings are explored, the most likely of which is lack of complete resection at the onset failed to identify the whole of the neoplasm. We conclude that pediatric epidermoid cysts of the pineal region should always receive close follow-up, particularly when total resection is not performed.     

Primary intracranial squamous cell carcinoma arising in an epidermoid cyst--a case report and review of literature

Primary intracranial squamous cell carcinoma is extremely rare, with most of the cases arising from malignant transformation of an epidermoid or a dermoid cyst. We report here a case of a 45-year-old male patient who presented with 1-month history of intermittent headache and recent onset of altered sensorium. Imaging revealed a midline posterior fossa mass lesion compressing the fourth ventricle and causing hydrocephalus. A provisional diagnosis of dermoid cyst was considered. Histopathological examination revealed a squamous cell carcinoma possibly arising from an underlying epidermoid cyst. This entity is being reported for its rarity.     

Cysticercosis of the cerebellopontine angle cistern mimicking epidermoid inclusion cyst

We report a case of a cystic lesion in the left cerebellopontine (CP) angle cistern. The magnetic resonance (MR) imaging features closely resembled an epidermoid inclusion cyst, and was interpreted as such. However, at surgery and on histopathological examination the lesion was found to be a cysticercus cyst. It may be impossible to distinguish between the two by imaging. The MR imaging findings of cysticercosis, epidermoid and other common differentials are discussed.     

Posttraumatic intradiploic arachnoid cyst of the posterior fossa

We report the case of a 5-year-old girl with an enlarging suboccipital mass, a posttraumatic intraosseous arachnoid cyst. Diagnostic work-up revealed that the lesion consisted of an intradiploic arachnoid cyst and an extra-axial occipital pouch that communicated by way of an osseous and dural defect. Surgical repair was undertaken with good results. A search of the current literature has shown only seven previous reports of leptomeningeal cysts situated at the occipital bones, most of them the result of an antecedent skull fracture. A pathogenetic hypothesis is presented comparing the growth of arachnoid intraosseous cysts and the development of meningocencephaloceles. Received: 1 October 1996