Intracranial Epidermoid Tumor With Changes in Signal Intensity on Magnetic Resonance Imaging Because of Non-hemorrhagic Pathology -Case Report-

Abstract

A 61-year-old woman presented an intracranial epidermoid tumor manifesting as dizziness and right facial hypesthesia. Magnetic resonance (MR) imaging revealed a well-defined lobulated mass in the right cerebellopontine angle as nearly isointense to the cerebrospinal fluid (CSF) on both T 1 -and T 2 -weighted images but inhomogeneously hyperintense on fluid-attenuated inversion recovery images. MR imaging performed 1 year later revealed that the tumor had significantly enlarged, and now appeared hyperintense to the CSF on T 1 -and T 2 -weighted images. The lesion was confirmed at surgery to be an epidermoid tumor filled with xanthochromic fluid. Histological examination found no evidence of hemorrhage in the resected tumor, so the changes in the MR imaging signal intensity were attributed to changes in the protein concentration of the intratumoral fluid, accumulation of debris, or some other non-hemorrhagic process.

White epidermoid cyst transformation after stereotactic radiosurgery: illustrative case

“…7 In contrast, WECs have a relatively high viscosity and protein concentration because inflammation, infection, and keratin desquamation result in degeneration of the cyst wall and increased protein levels. [8][9][10] The present case also suggested histopathological changes before and after the WEC transformation. As mentioned earlier, there are various reports on the pathological findings of WECs; however, the detailed pathological mechanism of the occurrence of WECs has not been fully clarified.…”

Hemorrhagic Epidermoid Cyst in Cerebellar Vermis: Case Report and Review of the Literature

“…3,5 Importantly, sudden development of symptoms and exponential growth of EC with a novel finding of contrast enhancement seen on imaging studies may suggest malignant transformation. 2,4,[14][15][16][17] Although extremely rare, malignant transformation into squamous cell carcinoma confers poor prognosis. 16 Careful histological examination of hyperdense EC lesions is essential to differentiate EC from other diseases, and to rule out malignant transformation, which would require adjuvant therapy after surgery.…”

Imaging alterations due to squamous metaplasia in intracranial neurenteric cysts: A report of two cases

“…In this regard, it has been reported that hypointensity on T2WI of neurenteric cysts is consistent with squamous metaplasia and voluminous keratinous debris. 2 Muto et al 18 discussed about signal intensity changes in MRI of epidermoid cysts, speculating that the amount of protein, free water, and keratin in the cyst correlate with the inflammation, infection, or desquamation of the cyst wall. In these contexts, we consider that the trigger of MRI signal intensity alterations in our cases might be a chronic inflammation due to a mechanical or a chemical stimulation such as cyst rupture or surgical impact.…”