Surgical resection of large encephalocele: a report of two cases and consideration of resectability based on developmental morphology.
BACKGROUND
The first-line treatment of encephalocele is reduction of herniated structures. Large irreducible encephalocele entails resection of the lesion. In such case, it is essential to ascertain preoperatively if the herniated structure encloses critical venous drainage.


METHODS
Two cases of encephalocele presenting with large occipital mass underwent magnetic resonance (MR) imaging. In first case, the skin mass enclosed the broad space containing cerebrospinal fluid and a part of occipital lobe and cerebellum. The second case had occipital mass harboring a large portion of cerebrum enclosing dilated ventricular space. Both cases had common venous anomalies such as split superior sagittal sinus and high-positioned torcular herophili. They underwent resection of encephalocele without subsequent venous congestion. We could explain the pattern of venous anomalies in encephalocele based on normal developmental theory.


CONCLUSIONS
Developmental theory connotes that major dural sinuses cannot herniate into the sac of encephalocele. Irrespective to its size, encephalocele can be resected safely at the neck without subsequent venous congestion.
Department of Neurosurgery, Hiroshima University Graduate School of Biomedical and Health Sciences, 1-2-3, Kasumi, Minami-ku, Hiroshima, Hiroshima, 734-8551, Japan. m.d.hideoohba1208@gmail.com.
Hideo
H
Ohba
Department of Neurosurgery, Hiroshima University Graduate School of Biomedical and Health Sciences, 1-2-3, Kasumi, Minami-ku, Hiroshima, Hiroshima, 734-8551, Japan.
Satoshi
S
Yamaguchi
Department of Neurosurgery, National Hospital Organization Higashihiroshima Medical Center, 513, Jike, Saijo-cho, Higashihiroshima, Hiroshima, 739-0041, Japan.
Takashi
T
Sadatomo
Department of Neurosurgery, Hiroshima University Graduate School of Biomedical and Health Sciences, 1-2-3, Kasumi, Minami-ku, Hiroshima, Hiroshima, 734-8551, Japan.
Masaaki
M
Takeda
Department of Neurosurgery, Hiroshima University Graduate School of Biomedical and Health Sciences, 1-2-3, Kasumi, Minami-ku, Hiroshima, Hiroshima, 734-8551, Japan.
Manish
M
Kolakshyapati
Department of Neurosurgery, Hiroshima University Graduate School of Biomedical and Health Sciences, 1-2-3, Kasumi, Minami-ku, Hiroshima, Hiroshima, 734-8551, Japan.
Kaoru
K
Kurisu
D003392:Cranial Sinuses / Q000000981:diagnostic imaging / Q000473:pathology*; D004677:Encephalocele / Q000000981:diagnostic imaging / Q000601:surgery*; D006801:Humans; D007231:Infant, Newborn; D018810:Magnetic Resonance Angiography; D008279:Magnetic Resonance Imaging; D008297:Male; D019651:Plastic Surgery Procedures / Q000379:methods*; D015898:Tomography Scanners, X-Ray Computed
Abnormal venous system; Developmental morphology; Dural sinus; Encephalocele; Magnetic resonance imaging; Neural tube defect