Petrous Apex Cephaloceles: Radiology Features and Surgical Management of a Rare Entity

Contributions of Laurent Princeteau to Trigeminal Neuralgia and Middle Fossa Anatomy: More than a Mere Tubercle

The contributions of Laurent Princeteau (1858-1932) to anatomy and to the establishment of neurosurgery have largely gone unrecognized, perhaps because he was educated and practiced in a French city other than Paris at a time when Paris was one of the chief centers of medicine in Europe. After completing a thesis describing an iliac artery anomaly and obtaining the distinguished agrégé teaching degree, Princeteau began his surgical career at the University of Bordeaux. Within 10 years, he became chef de clinique and one of the busiest surgeons in Saint-André Hospital, as well as head of the anatomy institute and professor of anatomy at the dental school. In 1891, he achieved the rank of surgeon. In the field of general anatomy, he was recognized for novel cadaveric preparations and vascular perfusion techniques. In the neurosciences, he made important contributions to the anatomy of the trigeminal nerve and trigeminal neuralgia. In 1898, Princeteau supervised a thesis that addressed contemporary surgical approaches to the trigeminal complex. In the course of this effort, he identified a bony prominence near the petrous apex (the retrogasserian tubercle) that helped to locate the gasserian ganglion. The surgical significance of the retrogasserian tubercle was quickly acknowledged in the European neurosurgical community and was noted in French textbooks of anatomy. Thierry de Martel, a founding member of the French neurosurgical School, named the tubercle after Princeteau. To the rest of the world, however, it remained almost unknown.

Incidental Petrous Apex Cephalocele Presenting With Transient Global Amnesia: A Case Report and Rapid Literature Review

Transient global amnesia (TGA) constitutes a rare clinical entity that manifests with temporary memory without any other neurological manifestation. Several pathogenetic mechanisms have been implicated, including temporal hypoperfusion, venous congestion, and cortical spreading potentials. Accordingly, the only relevant imaging findings are hippocampal CA1 areas of restricted diffusion on diffusion-weighted images. In the current case report, we present the rare case of a patient with TGA associated with bilateral petrous apex cephalocele (PAC). A 63-year-old female presented with a single episode of transient memory. The brain MRI showed a bilateral PAC and an empty sella. The patient was neurologically intact upon examination and was conservatively managed. There was no symptom recurrence during the six months of follow-up. We hypothesize that the presence of the meningocele could be associated with the pathogenesis of TGA. To the best of our knowledge, this is the first case of a petrous apex meningocele presenting with TGA. Most previously reported patients were females in their fourth decade of life, usually presenting with headaches or incidentally. Almost half of the cases were bilateral, with an empty sella. Surgical treatment was reserved for symptomatic patients with cerebrospinal fluid leaks and excruciating trigeminal neuralgia. Patients with TGA may be associated with temporal lesions, including PAC. Likewise, PAC is an extremely rare clinical entity that could occasionally present with TGA.

Posterior Skull Base Anatomy and Pathology

A posterior skull base lesion is an uncommon radiological finding that may be noted incidentally or during targeted imaging of patients with clinical symptoms attributable to the lesion. It may be inflammatory or neoplastic in etiology, or may simply be an anatomic variant or a "don't-touch" lesion that should not be misinterpreted as something more ominous. A systematic approach to the evaluation of the posterior skull base is therefore required in order to differentiate lesions requiring immediate attention from those requiring a less urgent course of action or none at all. This review will focus on the imaging features of pathologic conditions that are more commonly encountered in posterior skull base CT and MR examinations.