Malignant lymphomatous invasion of Meckel’s cave: pathoanatomical considerations of the petrous apex

Secondary central nervous system lymphoma is rare, occurring in up to 10% of non-Hodgkin's lymphoma patients and in 5% of diffuse large B-cell lymphoma patients. The prognosis is poor, even rarer is metastasis of large B-cell lymphomas into Meckel’s cave and the trigeminal nerve roots. We describe a relapsing case of a large B-cell lymphoma that migrated into Meckel’s cave, the mandibular branch of the trigeminal nerve and the adjacent cavernous sinus. We review petrous apex anatomy, review the literature of metastatic spread into Meckel’s cave and analyse existing pathoanatomical studies that explain the conduits and barriers of tumour spread. Understanding this pathoanatomical relationship is critical for neurologists and neurosurgeons alike to effectively correlate patient signs and symptoms to intracranial pathology and identify origins and sites of metastatic dispersion in similar rare clinical scenarios.

Microsurgical Resection of a Petroclival Epidermoid Cyst Using an Anterior Petrosectomy Approach: 2-Dimensional Operative Video

Epidermoid cysts are rare, benign lesions that result from inclusion of ectodermal elements during neural tube closure.1 Cysts are composed of desquamated epithelial cells and restrict diffusion on magnetic resonance imaging (MRI).2,3 Symptoms are attributable to anatomic location.4,5 In this video, we illustrate the surgical treatment of an epidermoid cyst located in the right cerebellopontine angle, petrous apex, and Meckel's cave. The patient, a 33-yr-old female with right-sided V1 trigeminal hypoesthesia, underwent surveillance imaging for 2 yr. However, she developed progressive V1 and V2 trigeminal hypoesthesia and imaging revealed enlargement of the lesion. Therefore, surgical resection was pursued. The patient consented to the procedure. The patient underwent a right middle fossa craniotomy and anterior petrosectomy. After identifying the greater superficial petrosal nerve and cutting the middle meningeal artery as it exited foramen spinosum, Kawase's triangle was drilled, and the dura over Meckel's cave and the subtemporal dura were opened. The lesion was resected, taking care to preserve the trigeminal nerve and the basilar artery. A retrosigmoid craniotomy was then fashioned. The cyst and its capsule were dissected off the brainstem and cranial nerves utilizing natural corridors between the trigeminal and vestibulocochlear nerves as well as between the facial and lower cranial nerves. Gross total resection was confirmed on postoperative MRI, and she was discharged home on postoperative day 5. Three months after surgery, she underwent formal pinprick testing, which revealed 95% loss of sensation in V1, 20% loss in V2, and normal sensation in V3. Three-month postoperative MRI showed no residual tumor.

Cavum trigeminale cephalocele associated with intracranial hypertension in an 18-month-old child: illustrative case

BACKGROUND Cavum trigeminale cephaloceles (CTCs) are characterized by a cystic appearance and extension of the posterolateral aspect of Meckel’s cave into the superomedial portion of the petrous apex. A possible mechanism is a transient or sustained increase of intracranial pressure transmitted to Meckel’s cave, leading to its secondary herniation, in the presence of predisposing local factors. The majority of CTCs are incidental findings. Among symptomatic cases, headache, trigeminal neuralgia, cerebrospinal fluid leak, vertigo, ataxia, facial numbness, hearing loss, diplopia, and other visual disturbances have been described. OBSERVATIONS The authors describe a case of an 18-month-old male patient referred to their hospital with drowsiness, vomiting, left cranial nerve VI palsy, and papilledema. Neuroradiological investigation revealed the presence of a CTC with a swollen aspect of the left pontine hemisection and indirect signs of intracranial hypertension. The patient was managed with implantation of a ventriculoperitoneal shunt. LESSONS CTCs are rare lesions that are difficult to recognize on neuroimaging, in which they can be mistaken for tumoral or inflammatory lesions. The most frequent asymptomatic forms should be considered as “leave-me-alone” lesions. In cases of intracranial hypertension, according to a supposed theory on the origin of CTCs, the authors recommend treating only the intracranial hypertension instead of performing more invasive surgical procedures, especially in pediatric patients.

Endoscopic-Assisted Microsurgical Resection of Right Recurrent Meckel's Cave Meningioma Extended to Cavernous Sinus

Objective This study was aimed to present the complete removal of a large recurrent Meckel's cave meningioma. Design This study is a case report. Setting The study was conducted at Department of Neurosurgery and Skull Base Laboratory at Lariboisiére Hospital, Paris. Participant A 53-year-old male was presented with a severe V1, V2, and V3 hypoesthesia and pain. He was operated 7 years ago for a right Meckel's cave meningioma with postoperative V1–V2 hypoesthesia. Magnetic resonance imaging (MRI) showed a large tumor recurrence extending into the cavernous sinus (CS), posterior fossa (PF), sphenoid sinus (SS), pterygopalatine (PPF), and infratemporal fossa (ITF; Fig. 1). Main Outcome Measures Radiological results and postoperative course were assessed for this study. Results The previous right frontotemporal approach was used. The lateral wall of the orbit, the middle fossa floor and the anterior temporal base were drilled to expose the orbit, PPF, and ITF. Foramen ovale (FO), foramen rotondum (FR), and superior orbital fissure (SOF) were opened. The meningoorbital band was cut and the lateral wall of CS was elevated (Fig. 2). The inferior orbital fissure was opened and tumor removed into the ITF, PPF, and orbit. After entering Meckel's cave from above, tumor was removed from PF. After microsurgical tumor removal, a 45-degree endoscope was used to remove tumor remnant and mucosa into SS. A watertight dural closure with pericranium was performed, reinforced with autologous fat and fibrin glue. Postoperative MRI showed complete tumor resection (Fig. 1). The patient experienced a right-side keratitis that resolved within 10 days and a V3 hypoesthesia that improved at 2 months. Conclusion This surgical case shows how the anatomical knowledge is mandatory in skull base surgery and how the integration of microsurgical and endoscopic-assisted techniques allows to obtain optimal results.The link to the video can be found at: https://youtu.be/qxt_389AdWU.