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.
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.
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.