Concurrent occurrence of squamous cell carcinoma in a cerebellopontine angle epidermoid cyst: A case report and review of the literature
- Department of Neurosurgery, Tel Aviv Medical Center, Dana Children’s Hospital, Tel Aviv, Israel.
- Department of Pathology, Tel Aviv Medical Center, Dana Children’s Hospital, Tel Aviv, Israel.
- Departments of Neurosurgery and Pediatric Neurosurgery, Dana Children’s Hospital, Tel Aviv, Israel.
Jonathan Roth, Department of Pediatric Neurosurgery, Dana Children’s Hospital, Tel-Aviv Medical Center, Tel-Aviv, Israel. Department of Neurosurgery, Tel-Aviv Medical Center, Tel-Aviv, Israel Tel-Aviv University, Tel-Aviv, Israel.
DOI:10.25259/SNI_726_2022Copyright: © 2022 Surgical Neurology International This is an open-access article distributed under the terms of the Creative Commons Attribution-Non Commercial-Share Alike 4.0 License, which allows others to remix, transform, and build upon the work non-commercially, as long as the author is credited and the new creations are licensed under the identical terms.
How to cite this article: Segev Gabay1, Marga Serafimova1, Michal Raz2, Jonathan Roth3. Concurrent occurrence of squamous cell carcinoma in a cerebellopontine angle epidermoid cyst: A case report and review of the literature. 28-Oct-2022;13:500
How to cite this URL: Segev Gabay1, Marga Serafimova1, Michal Raz2, Jonathan Roth3. Concurrent occurrence of squamous cell carcinoma in a cerebellopontine angle epidermoid cyst: A case report and review of the literature. 28-Oct-2022;13:500. Available from: https://surgicalneurologyint.com/surgicalint-articles/11954/
Background: Intracranial epidermoid cysts are rare benign lesions. Cases of malignant transformation (MT) into squamous cell carcinoma (SCC) have rarely been reported. We present a case of concurrent occurrence of SCC diagnosed during primary resection of epidermoid cyst (EC) and a relevant literature review.
Case Description: A 61-year-old patient was diagnosed with a right cerebellopontine angle (CPA) lesion after suffering from vertigo, diplopia, and right trigeminal (V2) hypoesthesia. Brain magnetic resonance imaging (MRI) showed a lesion consistent with an EC, demonstrating restricted diffusion with rim-enhancing area on the medial side of the cyst. During resection, two different tissue pathologies were observed, one consistent with an epidermoid (which was completely removed) and an additional firm tissue adherent to the brainstem, preventing gross total resection. Pathological evaluation confirmed two separate histologies – epidermoid and SCC. The patient never recurred to complete the recommended radiotherapy. Eleven months following surgical resection, a follow-up MRI showed local massive recurrence of the enhancing lesion. He was, further, treated with radiotherapy and is currently being followed up.
Conclusion: MT of an intracranial EC to SCC is rare and associated with poor prognosis. SCC may be found incidentally at time of primary resection or arise from a remnant of previously operated EC. Thus, aggressive complete resection should be intended, and separate pathological specimens should be sent from any abnormal region of the tumor.
Keywords: Epidermoid cyst, Intracranial, Malignant transformation, Squamous cell carcinoma
Intracranial epidermoid cysts (IECs) are extra-axial, usually congenital lesions that arise from trapped epithelium during gestation.[
IECs typically cause symptoms resulting from local mass effect on surrounding neural structures. In rare cases, the epithelium lining of the cyst can undergo malignant transformation (MT) into squamous cell carcinoma (SCC), which occurs predominantly in the fourth and fifth decades of life.[
A 61-year-old male patient presented to our clinic with several weeks of episodic vertigo, diplopia, and right trigeminal (CN V2) hypoesthesia. A magnetic resonance imaging (MRI) examination showed an extra-axial lobulated mass, measuring 22 × 25 × 35 mm, in the right CPA, causing significant pressure on the adjacent cerebellar lobe and brainstem, although, without hydrocephalus. The lesion demonstrated characteristic radiological features consistent with an EC, including hypointensity on T1-weighted image (T1WI), hyperintensity on T2-weighted image (T2WI) with some T2 hypointensities areas in the anterior-medial periphery, correlating with keratin, and restriction on diffusion-weighted image (DWI). A small enhancing region was present on the medial side of the lesion [
Preoperative magnetic resonance imaging (MRI) T1 + c – coronal (upper left) and axial (upper right) view – demonstrating hypointense T1 right cerebellopontine angle lesion, with a small enhanced area on the medial side of the lesion. Preoperative MRI T2 demonstrating hyperintensity on T2-weighted image with focal areas of hypointensities in the periphery (lower left), correlating with keratin. Restricted diffusion is seen on diffusion-weighted image (lower right).
A right retrosigmoid suboccipital craniotomy was done with electrophysiological monitoring including electromyography of CN 5, 7, as well as brainstem auditory-evoked response, in addition to transcranial motor-evoked potential monitoring and somatosensory-evoked potentials. During surgery, two different tissue pathologies were observed, one consistent with a typical epidermoid tumor, for which a near gross total resection (GTR) was achieved, which could be evident on a postoperative MRI. In addition, a different tissue with firm consistency was recognized that was adherent to the brainstem, preventing GTR, leaving the small enhancing region on the medial side of the lesion as seen on the postoperative MRI.
The pathological evaluation confirmed the presence of two separate histologies. The first specimen demonstrated areas of simple squamous epithelial cyst with mounds of layered keratin, typical of EC [
The patient was recommended radiotherapy, yet for unknown reasons, he never showed up for treatment. Eleven months following surgical resection, a follow-up MRI showed a local massive recurrence of the enhancing lesion [
The occurrence of SCC intracranially is usually a result of metastases or direct extension from a primary location outside the central nervous system (CNS)4. The primary SCC is extremely rare and is usually the result of MT of benign IEC.[
Preoperative diagnosis of MT of an IEC, based on radiological features, is challenging, and ultimately, a definite diagnosis depends on histopathological examination. IECs typically have characteristic radiological features, specifically low-signal intensity on T1WI and high-signal intensity on T2WI, as well as strong restriction on DWI.[
There is a surgical advantage to preoperatively acknowledging that these two pathologies can coexist, for two main reasons – the first for biopsy, as in our case, where there were two different tissue consistencies, and the second, for the intended extent of resection. While extensive surgical resection aiming for GTR is currently the gold standard for the treatment of IECs, there is no defined standard of care for IECs undergoing MT.[
Intracranial SCCs are rare and aggressive tumors. The possibility of MT of an IEC should be always be considered and kept in the surgeon’s mind when approaching to resect such lesions. Preoperatively, MT should be suspected by rapid deterioration of symptoms and signs and aggressive radiological course. The co-occurrence of SCC and IEC is a rare and devastating event, changing the course of the disease. Separate pathological specimens should be sent from any visually distinguishing pathological tissue. Radiotherapy should be supplemented in cases of SCC. In addition, surgical resection should strive for GTR of IEC whenever possible, without compromising vital neurological functions. Postoperatively, a close clinical and imaging follow-up is recommended for any subtotally resected IEC.
Patient’s consent not required as patient’s identity is not disclosed or compromised.
There are no conflicts of interest
The views and opinions expressed in this article are those of the authors and do not necessarily reflect the official policy or position of the Journal or its management. The information contained in this article should not be considered to be medical advice; patients should consult their own physicians for advice as to their specific medical needs.
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