Meckel Cave Epidermoid Cyst Presenting as Multiple Cranial Nerve Deficits Due to Indirect Tumoral Compression of the Cavernous Sinus: A Case Report and Literature Review

The Riddle of the Double Vision-A Rare Case of Intracranial Tumor: When Imaging Resolves the Mystery

A 77-year-old-man with arterial hypertension, diabetes mellitus type II presented at our clinic for a routine ophthalmological exam. He complained of intermittent double vision. The ophthalmic examination revealed paralysis of III (n. oculomotorius) and VI (n. abducens) cranial nerves with ptosis, deficit in elevation and abduction of the left eye. The patient underwent urgent MRI imaging of the brain/orbits and paranasal sinuses, and urgent neurological assessment. MRI revealed a volume-occupying process, starting from the posterior wall of the left maxillary sinus with perineural diffusion and involvement of the homolateral trigeminal nerve, intracranial spread in the medial cranial fossa and involvement of the cavernous, sphenoidal sinuses and the orbital apex on the left side. Biopsy was performed, and the histology resulted in sinonasal squamous cell carcinoma with intracranial spread.

Avoiding the Blinded Funnel: A Combined Single Piece Fronto-Temporo-Orbito-Zygomatic Craniotomy Endoscopic-Assisted Approach with Multimodal Assistance for an Epidermoid Tumor of Meckel's Cave-Case Report

A Meckel's cave tumor poses a great challenge because of the peculiar neurovascular structure of the area and the deep location. Multiple surgical approaches have been designed for this area. In this report, we describe a case treated with a combined one step single piece fronto-temporo-orbito-zygomatic craniotomy (FTOZ) endoscopic-assisted approach for the treatment of an epidermoid tumor of Meckel's cave. A 51-year-old woman presented with a clinical history of left trigeminal neuralgia and paresthesia. CT imaging revealed a left basal temporal tumor. MR showed a tumor located in Meckel's cave near the cavernous sinus, with a good enhancement after gadolinium administration. The tumor was resected through a lateral basal subtemporal extradural approach followed by an intradural approach using intraoperative neuronavigation, endoscopic assistance, neurophysiological monitoring, and an intraoperative ultrasound probe. The lesion was completely removed. No new onset neurological damage has occurred. The symptoms improved following surgery. The aesthetic appearance of the patient was respected. The combined approach with a single piece fronto-temporo-orbito-zygomatic craniotomy has enabled us to work on a wider operating field to completely remove the lesion avoiding blind spots.

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.

Development of Integrated 3-Dimensional Computer Graphics Human Head Model

BACKGROUND

Understanding the complex anatomy of neurostructures is very important in various stages of medical education, from medical students to experienced neurosurgeons, and, ultimately, for the knowledge of human beings.

OBJECTIVE

To develop an interactive computer graphics (CG) anatomic head model and present the current progress.

METHODS

Based on the prior head 3-dimensional CG (3DCG) polygon model, 23 additional published papers and textbooks were consulted, and 2 neurosurgeons and 1 CG technician performed revision and additional polygon modeling. Three independent neurosurgeons scored the clear visibility of anatomic structures relevant to neurosurgical procedures (anterior petrosal and supracerebellar infratentorial approaches) in the integrated 3DCG model (i model) and patients' radiological images (PRIs) such as those obtained from computed tomography, magnetic resonance imaging, and angiography.

RESULTS

The i model consisted of 1155 parts (.stl format), with a total of 313 763 375 polygons, including 10 times more information than the foundation model. The i model was able to illustrate complex and minute neuroanatomic structures that PRIs could not as well as extracranial structures such as paranasal sinuses. Our subjective analysis showed that the i model had better clear visibility scores than PRIs, particularly in minute nerves, vasculatures, and dural structures.

CONCLUSION

The i model more clearly illustrates minute anatomic structures than PRIs and uniquely illustrates nuclei and fibers that radiological images do not. The i model complements cadaveric dissection by increasing accessibility according to spatial, financial, ethical, and social aspects and can contribute to future medical education.

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.

Unraveling a cephalalgic quagmire from a cavern to a cave

Headache in women in their late forties can be primary or secondary. We report a 48-year-old female with chronic slowly progressive left temporal headache for 1 year. She also had ipsilateral eye pain and facial numbness for 1 month, with restricted abduction in the left eye and diplopia. On neurological examination, she had isolated left abducent nerve palsy, with loss of corneal and conjunctival reflexes, localizing the pathology to the cavernous sinus or its adjacent structures. Anatomically, cranial nerves V and VI are in close proximity to each other in the region of Meckel's cave. In view of her age, insidious onset, progressive symptoms and clinical findings, the provisional diagnosis in this patient was a Meckel's cave tumor. Magnetic resonance (MR) imaging revealed a 2 cm × 2 cm × 1.7 cm enhancing dumb-bell-shaped mass lesion with mild restricted diffusion in the Meckel's cave projecting into cavernous sinus with alanine, myoinositol and glutamine peaks on MR spectroscopy. Intradural debulking was done; lesion was confirmed by histopathology and patient was cured of her symptoms. An algorithm for diagnosing this entity at the bedside is presented.

Epidermoid Cyst Extending Along Trigeminal Nerve Pathway with Unusual Imaging Findings

Epidermoid cysts (ECs) are benign extraaxial tumors. They frequently occur at the cerebellopontine angle and parasellar regions. However, they rarely occur in the Meckel's cave. Typically, ECs appear as a hypointense mass on T1-weighted magnetic resonance imaging (MRI) and hyperintense on T2-weighted MRI. However, ECs may occasionally present as hyperintense on T1-weighted imaging and hypointense on T2-weighted imaging. When this occurs, they are known as white epidermoid cysts. We present a case of a 25-year-old woman with a 3-month history of hypoesthesia in the distribution of the right trigeminal nerve. MRI showed a lesion located within the Meckel's cave. The MRI signal was heterogeneous, with hyperintense areas on T1-weighted images, being hypointense on T2-weighted imaging. Preoperative suspicion was trigeminal schwannoma with unusual radiologic features. Finally, the pathologic diagnosis was epidermoid cyst. Therefore to establish a proper preoperative diagnosis, one should be aware that ECs can occur in Meckel's cave and with unusual radiologic features, as occurred in the case described earlier.

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

Intracranial epidermoid cysts are benign lesions that typically remain asymptomatic; however, although histopathologically benign, these cysts can rarely undergo malignant transformation into squamous cell carcinoma. Primary intracranial squamous cell carcinoma carries a poor prognosis as optimal treatment modalities remain unclear due to their low incidence. Here, we present a case of a cerebellopontine angle epidermoid cyst remnant that underwent malignant transformation into squamous cell carcinoma 40 years after partial resection. To our knowledge, this case establishes the longest time interval to date for an intracranial epidermoid cyst to undergo malignant transformation. We also review the relevant literature and discuss recent retrospective clinical studies that have analyzed the effect of multimodal treatment approaches on survival outcomes in patients with these lesions.