Malignant squamous cell carcinoma arising in a previously resected cerebellopontine angle epidermoid

Abstract

Background:Malignant squamous cell differentiation of an epidermoid cyst can carry a significantly poor prognosis and very little is known about this entity.Case Description:We present the case of a 35-year-old lady, with primary malignant squamous cell carcinoma (SCC) arising from a previously partially resected cerebellopontine angle epidermoid cyst almost 5 years after initial resection. We also review the relevant literature.Conclusion:The imaging findings, histopathology, and management of a malignant SCC arising from a benign epidermoid cyst are discussed with recommendation for increased surveillance and follow-up, even for classically accepted benign lesions.

Intracranial epidermoid cyst with proliferative folliculosebaceous epithelium: Report of a rare case and discussion on pathogenesis

“…Furthermore, increases in size over a short course are rare . Nonetheless, previous reports have described epidermoid cysts undergoing malignant transformation into squamous cell carcinomas (SCC) . However, no reports have described epidermoid cysts similar to the present case, with repeated recurrences over a short period of time postoperatively and rapid proliferation accompanied by the presence of mature tissue such as hair follicles or sebaceous glands without malignant transformation, Here, we report a case of repeated recurrences regardless of so‐called pathologically “benign features” along with some pathological discussion of the case, in which the patient was diagnosed with epidermoid cyst with proliferative folliculosebaceous epithelium.…”

“…All surgeries performed at our hospital involved gross total removal, and histopathological examination of the entire tumor, rather than a small portion of the tumor, was conducted and subsequently discussed. Epidermoid cysts have been reported to undergo malignant transformation into SCC . However, to the best of our knowledge, no other reports have described an epidermoid cyst containing tissue that differentiated into mature ectodermal tissue and proliferated over a short period of time, as seen in the present case.…”

“…In the present case, speed of proliferation increased with every surgery, suggesting that the folliculosebaceous epithelium may have proliferated at an accelerated rate due to inflammatory responses in the tissue surrounding the tumor or remnant tumor tissue with repeated surgical invasion. Reports describing epidermoid cysts undergoing malignant transformation into SCC have also postulated the mechanisms involving inflammatory response to surgical invasion or leakage of cyst contents, but the factors that determine differentiation into proliferative folliculosebaceous epithelium or SCC are currently unknown.…”

Intracranial Squamous Cell Carcinoma Arising From a Cerebellopontine Angle Epidermoid Cyst Remnant Four Decades After Partial Resection

“…Our literature review found that it is extremely rare for MT of an EC to occur >5 years from initial surgery. Indeed, only 15 cases (excluding the present case) have been reported to date (Table 2) (2–16). Of the reported cases, age at diagnosis of malignant cyst transformation ranged between 37 and 74 years with an average age of 54 years.…”

“…Although classified as a benign entity based on histopathology and potentially curable with neurosurgical gross total resection, ECs can rarely undergo malignant transformation (MT) into squamous cell carcinoma (SCC). Since first described in 1912, only 15 cases of malignant cyst transformation have been reported to occur >5 years from time of initial surgery (2–16). Here, we describe a case of an EC remnant in the cerebellopontine angle (CPA) that underwent MT into SCC 40 years after partial resection.…”