Cerebellar Enterogenous Cyst with Atypical Appearance and Pathological Findings

The Rhomboid Lip: Anatomy, Pathology, and Clinical Consideration in Neurosurgery

OBJECTIVE

To describe microsurgical anatomy of the rhomboid lip (RL) and to consider its role by presenting histology and clinical cases.

METHODS

We examined 10 (20 sides) formalin-fixed adult human cadaveric heads injected with colored silicone. A total of 20 RLs were examined posteriorly. We examined the expansion of the RL in the cerebellopontine cistern. We assessed the relationship between the RL and choroid plexus and the RL and cranial nerve IX and classified the RL. We also observed these relationships in clinical cases during surgeries and examined histologic assessments of the RL.

RESULTS

The RL was divided into 3 types, non-extension type, lateral extension type, and jugular foramen type, according to the relationship between the RL and choroid plexus. There were many variations of the extension of the RL. The jugular foramen type was rare.

CONCLUSIONS

Histologically, the RL is the remnant of the fourth ventricle covered with ependymal cells. Knowledge of the detailed anatomy and proper dissection of the RL may help surgeons to obtain good visualization of structures around the foramen of Luschka.

Intracranial Enterogenous Cysts Close to the Brainstem Treated Through the Nerve Endoscope

Enterogenous cysts (ECs) are rare, inborn lesions of central nervous system, which mostly occurred in the ventral side of the spinal cord as well as common in children; adult intracranial cysts are rare. Although the morbidity of intracranial ECs is quite low, we also can make a preliminary diagnosis of those patients with the help of imaging examination. In this article, we introduced 1 case of ECs ventral to the brainstem, which present images on magnetic resonance imaging as hypointense lesions on T1-weighted and high-intensity mass on T2-weighted image. In consideration of the difficulty of the surgical approach and the surgical visual field exposure, we use microscope and nerve endoscope to design personalized surgical approach to minimize the surgical injury. Pathologic examination showed that it was typical EC. Not only is the location extremely rare, but also the surgical method is uncommon in this disease. We not only study the intracranial ECs' manifestations, but also discuss the surgical approach and the application of nerve endoscope of our choice,which aims to provides a new surgical therapeutic approach for these lesions.

A Rare Presentation of an Enterogenous Cyst as an Intra-Axial Pontine Lesion

A 56-year-old man was admitted to our hospital with intermittent right facial numbness for 1 year and instability on walking for 6 months. Magnetic resonance imaging revealed an ovoid and well-demarcated intra-axial pontine lesion. Cyst fenestration and biopsy were carried out, and the diagnosis of enterogenous cyst was made by magnetic resonance imaging and pathologic findings. Preoperative symptoms resolved completely 3 months after surgery and no evidence of recurrence was found during 3 years of follow-up. Although total resection of enterogenous cysts is recommended, cyst fenestration may be useful if the cyst is adherent to vital neurovascular structures.

An enterogenous cyst with atypical pathological findings and chemical meningitis

INTRODUCTION

Intracranial enterogenous cysts are rare and mainly occur in the posterior fossa. These cysts are usually extra-axial, midline, anterior to the brainstem, or at the cerebellopontine angle. We report a case of an enterogenous cyst in which diagnosis was difficult because the lesion showed atypical pathologic findings.

CASE PRESENTATION

A healthy 41-year-old man complained of paroxysmal occipital headaches lasting over a week, with increased severity for 3 days accompanied by slight dizziness and mild nausea. Magnetic resonance imaging showed a cystic lesion between clivus and brainstem. The patient underwent surgery for removal of the lesion via the right-sided far-later approach, and the lesion was resected totally. Although pathologic examinations showed a cyst had a mono-to-multilayered squamous epithelium, which are not accord with typical enterogenous cyst, the diagnosis was finally made based on the presence of basement membrane and immunohistochemical results.

DISCUSSION AND EVALUATION

To confirm the diagnosis of enterogenous cyst, further pathologic examinations were performed and immunohistochemical characters were summarized. Chemical meningitis, a rare complication of enterogenous cyst, happened in current case. Use a syringe and aspirate the contents before incision might be a procedure to prevent chemical meningitis.

CONCLUSIONS

To our knowledge, this is the first report of an enterogenous cyst associated with mono-to-multilayered squamous epithelium. Although during the follow-up time, no recurrence happened, long-term follow-up is needed.