Dumbbell-shaped intradiploic epidermoid cyst involving the dura mater and cerebellum

Giant Occipital Intradiploic Epidermoid Cyst

Intraparenchymal or intradiploic epidermoid cysts are very rare. Most of these cysts, when present, tend to involve the frontal and temporal lobes, and occasionally, the pineal gland or the brain stem. Here, we report a 45-year-old female, who presented with localized occipital headache and a tender occipital swelling, gradually increasing in size. She was hemodynamically and neurologically stable and did not have any focal neurological deficits. Whole skull and brain imaging revealed a well-demarcated expansile lytic lesion in the right occipital bone, which was hypointense on T1-weighted and hyperintense on both T2-weighted imaging and diffusion-weighted imaging without any contrast enhancement. The patient underwent a right occipital craniotomy and total excision of the intradiploic space occupying lesion. Histopathological examination confirmed the lytic bone lesion over occipital bone as intradiploic epidermoid cyst.

Traumatic intradiploic epidermoid cyst manifest as scalp papule

A posterior fossa intradiploic epidermoid cyst was removed from the calvarium of an otherwise healthy 34-year-old woman after work up for dizziness and blurry vision. The patient admitted to a history of a firm papule that occurred occasionally after a trauma sustained to the region years prior. The authors propose that trauma and cutaneous stigmata are potential associations with intradiploic epidermoid cysts.

Atypical intracranial epidermoid cysts: rare anomalies with unique radiological features

Epidermoid cysts are benign slow growing extra-axial tumours that insinuate between brain structures, while their occurrences in intra-axial or intradiploic locations are exceptionally rare. We present the clinical, imaging, and pathological findings in two patients with atypical epidermoid cysts. CT and MRI findings for the first case revealed an intraparenchymal epidermoid cyst that demonstrated no restricted diffusion. The second case demonstrated an aggressive epidermoid cyst that invaded into the intradiploic spaces, transverse sinus, and the calvarium. The timing of ectodermal tissue sequestration during fetal development may account for the occurrence of atypical epidermoid cysts.

An analysis of intracranial epidermoid tumors with malignant transformation: treatment and outcomes

OBJECTIVE

While typically benign, epidermoid tumors upon rare occasion can undergo malignant transformation, which carries a poor prognosis. Here, we reviewed treatment strategies and analyzed outcomes for every case of malignant epidermoid tumor reported since its original description in 1912.

METHODS

A comprehensive literature review identified all reported cases of malignant transformation of intracranial epidermoid tumor. Treatments were categorized as follows: palliative management, stereotactic radiosurgery (SRS), chemotherapy, and surgery plus multiple (2+) adjuvant therapies. Survival data of these groups were compared to treatment outcomes for patients receiving only surgical resection, as reported in our previous study.

RESULTS

We identified 58 cases of intracranial epidermoid tumor with malignant degeneration. Average survival regardless of therapy was 11.8 months. Mean survival outcomes for groups treated with palliative management, chemotherapy, SRS, and multiple postoperative adjuvant therapies were 5.3 months, 25.7 months, 29.2 months, and 36.3 months, respectively. Outcomes for the groups including SRS, chemotherapy, and multiple post-operative adjuvant therapies were statistically significant compared to surgical resection alone.

CONCLUSION

While there remains a lack of consensus regarding the best approach to the management of patients with malignant epidermoid tumors, our systematic analysis characterizes and confirms the added benefit of SRS, chemotherapy, and multimodal adjuvant therapies.

Clinical characteristics and diagnostic imaging of epidermoid tumors

Epidermoid tumors are rare, benign congenital lesions which typically present between the third and fifth decades of life. They are thought to originate from ectodermal cells misplaced during neural tube formation and separation. While epidermoids may present anywhere in the cranial vault, they are characteristically located intradurally and in a paramedian position within the cerebellopontine angle and parasellar regions. Although imaging results may vary depending upon cystic content, CT scanning generally reveals a well-circumscribed, nonenhancing, lobulated, hypodense mass. They are hypointense on T1-weighted MRI, and hyperintense on T2-weighted MRI, diffusion-weighted imaging and fluid-attenuated inversion recovery sequences. The use of appropriate neuroimaging should be utilized to differentiate epidermoids from other intracranial lesions. While gross total resection of these tumors is the definitive treatment to prevent recurrence and aseptic meningitis, a subtotal resection may be necessary to preserve neurological function.

Huge intradiploic epidermoid cyst

A 60-year-old man presented with an occipital mass under the scalp and complained of headache, nausea, and dizziness. Magnetic resonance imaging showed a well-defined mass in the occipital scalp extending from the scalp through the cranium and several centimetres into the posterior fossa. There were well-defined margins in the deep portion and the mass was totally removed. Histological examination showed that the cystic structure was lined by squamous epithelium containing laminated keratin material. The pathological findings were consistent with the diagnosis of an epidermoid cyst. The patient was discharged free of symptoms.

Primary intradiploic pterional epidermoid cyst

A 72-year-old woman who developed a left temporal protrusion was referred to our center. An MRI showed a heterogeneous mass in the left temple with T2 signal hyperintensity within the intradiploic space of the greater wing of the sphenoid bone, measuring 2.4 x 2.1 cm. The patient underwent a surgical removal of the mass through the pterional approach. Pathology showed an epidermoid cyst. Intradiploic epidermoid cysts of the skull are rare benign tumors of the skull. These lesions grow slowly and are composed of epidermoid cells debris rich in cholesterol. The prophylactic removal of these tumors with the goal of preventing recurrences is recommended.