Basal Encephalocele in an Adult Patient Presenting With Minor Anomalies

A Case Report

Naoyuki Harada; Masaaki Nemoto; Chikao Miyazaki; Kosuke Kondo; Hiroyuki Masuda; Jun Nomoto; Nobuo Sugo; Takao Kuroki

Disclosures

J Med Case Reports. 2014;8(26) 

In This Article

Abstract and Introduction

Abstract

Introduction Basal encephalocele is rare in adults. Congenital and acquired cases have been reported with regard to the developmental mechanism, and the pathology has not been elucidated in detail.

Case presentation We encountered an adult with basal encephalocele strongly suggesting congenital development because of the presence of minor anomalies: strabismus and ocular hypertelorism. The disease manifested as persistent spontaneous cerebrospinal fluid rhinorrhea and repeated meningitis in a 66-year-old Japanese man. On computed tomography, brain tissue protruded through a part of the ethmoid bone of his right anterior skull base, and it was diagnosed as transethmoidal-type basal encephalocele. Regarding his facial form, the distance between his bilateral eyeballs was large compared to his facial width, and his canthal index (defined as inner to outer inter canthal ratio × 100) was calculated as 38.5, based on which it was judged as ocular hypertelorism. In addition, his right eyeball showed strabismus. A right frontotemporal craniotomy was performed for spontaneous cerebrospinal fluid rhinorrhea, and the defective dura mater region was patched with temporal fascia.

Conclusions Mild minor anomalies that require no treatment are overlooked in adults, but the presence of several anomalies increases the possibility of congenital disease. Therefore, it may be necessary to examine minor anomalies in cases of adult basal encephalocele when considering the possibility that the disease may be congenital.

Introduction

Basal encephalocele is an uncommon congenital malformation occurring in one in 35,000 to 40,000 live births.[1] Brain tissue protrudes through bony defects in the cribriform plate and body of the sphenoid or ethmoid. Based on the anatomical position of these bony defects, the disease is roughly divided into transethmoidal and transsphenoidal types.[2] Several mechanisms have been proposed to explain the occurrence of basal encephalocele. The most widely accepted theory proposes the occurrence of neuroschisis after neural tube closure.[2] Thus, basal encephalocele is often complicated by midfacial malformation and minor anomalies, such as hypertelorism, anterior cranium bifidum, nasal cleft, cleft lip, cleft palate, and bifid uvula, and most cases are diagnosed at birth.[2,3] By contrast, basal encephalocele diagnosed in adulthood is difficult to diagnose in childhood because abnormalities of the countenance are lacking, and it is incidentally found with spontaneous cerebrospinal fluid rhinorrhea in many cases.[1,4–9] Acquired cases of basal encephalocele have been reported in adults;[10] the pathology of basal encephalocele in adults has not yet been elucidated.

We encountered an adult with a basal encephalocele strongly suggesting congenital development because of the presence of minor anomalies: strabismus and ocular hypertelorism.

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