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

Giant epidermoid cyst penetrating the skull: a case report and literature review

Intracranial epidermoid cyst is a rare pseudotumor of the nervous system, accounting for 0.2%-1.8% of all intracranial tumors. It is usually located in the cerebellopontine Angle or parasellar area, with insipid onset, slow growth and usually less than 2 cm in diameter. Giant epidermoid cysts that invade the bone have rarely been reported in the literature. Herein, we report a case of giant ECs extradural to the parietal bone, penetrating the skull and continuing to expand outward. In addition, a systematic search of four authoritative databases was conducted to collect the relevant reports of giant epidermoid cyst with diameter > 5cm for the first time, and to discuss the clinical and radiographic features of patients with giant epidermoid cyst and the influence of treatment options.

Epidermoid cyst in atypical intracranial areas transformed to epidermoid carcinoma: a case report

Intracranial epidermoid cysts, also known as epidermal cysts, grow slowly and may be occult. When small, epidermoid cysts are usually clinically unremarkable or cause no definitive symptoms. At typical sites, they are easily found through magnetic resonance imaging, which aids evaluation before surgery. However, in rare cases, epidermoid cysts are situated in unusual locations or transformed to malignancy, and preoperative misdiagnosis is possible. Here, the case of a 58-year-old male patient who presented with weakness in the left lower limb and was diagnosed with a malignant epidermoid cyst in the right frontoparietal lobe, right lateral ventricle, is reported. Surgery was performed to remove the tumour followed by radiotherapy, and the patient was reported to be living independently after approximately 11 months of follow-up.

Intracranial squamous cell carcinoma of the cerebello-pontine angle mimicking a cystic acoustic schwannoma. A case report with discussion of differential diagnosis and review of literature

We report a case of a primary intracranial squamous cell carcinoma (SCC) of the cerebello-pontine angle extending through the internal auditory canal, with the unusual presentation of a completely cystic lesion with no diffusion restriction, internal necrotic-hemorrhagic changes and peripheral enhancement, mimicking a cystic acoustic schwannoma. The lack of diffusion restriction and the peripheral enhancement along the lesion, 2 unique findings, supposedly reflected complete cancerization of the epidermoid cyst from which the SCC originated. We discuss the differential diagnosis and review the literature on primary intracranial SCC.

Concurrent occurrence of squamous cell carcinoma in a cerebellopontine angle epidermoid cyst: A case report and review of the literature

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.

Brain lymphoma development related to a long lasting epidermoid cyst

INTRODUCTION

Epidermoid cysts (EC) are benign and slow growing lesions. A primary brain lymphoma development related to a EC is presented, second case described in literature.

CASE PRESENTATION

A woman 40 years old, harbouring a EC for more than 20 years, develops a fast growing brain lesion next to the EC. Surgery was performed and diagnosis was primary diffuse B cells lymphoma.

DISCUSSION

Malignant transformation of EC has been described, usually to squamous cells carcinoma, and much less frequently, to another tumours. Inflammatory mechanisms have been advocated to explain this evolution. Chronic inflammation and lymphoma genesis are related, and this could be the mechanism behind this rare evolution of an EC.

CONCLUSIONS

Even being benign lesions, EC can develop malignant tumours due to the chronic inflammation secondary to them.

Primary Squamous Cell Carcinomas Arising in Intracranial Epidermoid Cysts: A Series of Nine Cases and Systematic Review

Objective

Primary squamous cell carcinomas (PSCCs) arising in intracranial epidermoid cysts (IECs) are very rare, and their management and prognostic factors remain unclear. This study aimed to enunciate the clinical features and suggest a treatment protocol based on cases from the literature and the cases from our institution.

Methods

The clinicoradiological data were obtained from nine patients with PSCCs arising in IECs, who underwent surgical treatment at Beijing Tiantan Hospital between July 2012 and June 2018. We also searched the PubMed database using the keywords “epidermoid cyst(s)” or “epidermoid tumor(s)” combined with “malignant” or “malignancy” or “intracranial” or “brain” or “squamous cell carcinoma” between 1960 and 2020. Risk factors for overall survival (OS) were evaluated in the pooled cohort.

Results

The mean age of our cohort was 51.2 ± 8.3 years (range: 39–61 years), which included eight males and one female. Gross total resection (GTR) was achieved in three patients, while non-GTR was achieved in six patients. Radiotherapy was administered to five patients. After a median follow-up of 16.7 ± 21.6 months (range: 3–72 months), eight patients died with a mean OS time of 9.75 ± 6.6 months (range: 3–23 months). In the literature between 1965 and 2020, 45 cases of PSCCs arising in IECs were identified in 23 males and 22 females with a mean age of 55.2 ± 12.4 years. GTR, non-GTR, and biopsy were achieved in six (13.3%), 36 (80%), and three (6.7%) cases, respectively. After a mean follow-up of 12.7 ± 13.4 months (range: 0.33–60 months), 54.1% (20/37) patients died, and recurrence occurred in 53.6% (15/28) patients. A multivariate analysis demonstrated that postoperative radiotherapy (p = 0.002) was the only factor that favored OS. The Kaplan–Meier analysis showed that, compared with no radiotherapy (median survival time: 4 months), radiotherapy (median survival time: 24 months) had significantly prolonged OS (p = 0.0011), and GTR could not improve OS (p = 0.5826), compared with non-GTR. The 1-year OS of patients with or without radiotherapy was 72.5% or 18.2%, respectively.

Conclusion

Malignant transformation of IEC into PSCC was prevalent in elderly patients, with slight male predominance. GTR of previous benign IECs is recommended. For remnant benign IECs, close follow-up should be performed. Postoperative radiotherapy for PSCCs could bring survival benefit. GTR of these malignant intracranial tumors is difficult when they involve important brain structures. Future studies with larger cohorts are necessary to verify our findings.

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

Intracranial epidermoid cysts are slow growing congenital avascular neoplasms that spread across the basal surface of the brain. They most commonly occur in the paramedial region in the cerebellopontine angle and the parasellar region. Despite its generally benign nature, sporadically they can be accompanied with hemorrhage or very rarely undergo malignant transformation. The authors present a case report of a patient with a hemorrhagic vermian epidermoid cyst and a review of all published similar cases.

Brain lymphoma development related to a long lasting epidermoid cyst

INTRODUCTION

Epidermoid cysts (EC) are benign and slow growing lesions. A primary brain lymphoma development related to a EC is presented, second case described in literature.

CASE PRESENTATION

A woman 40 years old, harbouring a EC for more than 20 years, develops a fast growing brain lesion next to the EC. Surgery was performed and diagnosis was primary diffuse B cells lymphoma.

DISCUSSION

Malignant transformation of EC has been described, usually to squamous cells carcinoma, and much less frequently, to another tumours. Inflammatory mechanisms have been advocated to explain this evolution. Chronic inflammation and lymphoma genesis are related, and this could be the mechanism behind this rare evolution of an EC.

CONCLUSIONS

Even being benign lesions, EC can develop malignant tumours due to the chronic inflammation secondary to them.

Surgery and dose-escalated radiotherapy for a de novo intracranial squamous cell carcinoma of the cerebellopontine angle

We report an extremely rare case of de novo intracranial squamous cell carcinoma of the cerebellopontine angle. The patient underwent craniotomy for debulking of the lesion to relieve mass effect on the brainstem and to establish a tissue diagnosis. Cancer staging revealed no other primary cancers and no evidence of metastatic disease. Postoperatively, he received image-guided intensity-modulated radiotherapy to the tumor bed followed by fractionated radiosurgery boost to the gross residual disease for a total average dose of 7000 cGy. He had a complete response to radiation and remains 42-months' disease-free post-treatment.

Primary Intracranial Squamous Cell Carcinoma with a Fatal Course

Intracranial squamous cell carcinomas (SCCs) are extremely rare. They can be primary or represent a degeneration of an epidermoid cyst (EC). We report the case of a patient operated, with an endoscopic transnasal approach, for a primary intracranial SCC. The optimal management for patients with primary intracranial SCC or ECs which have undergone malignant degeneration has yet to be identified.