Resection of a lateral supratentorial endodermal cyst complicated by postoperative seizures: A case report

Abstract

Background: Endodermal cysts are uncommon cystic lesions usually located at the ventral aspects of the spine. A lateral supratentorial location of such cysts is extremely rare. A unique case of a lateral supratentorial endodermal cyst that required surgical intervention due to uncal herniation, complicated with postoperative seizures, is presented.

Case description: A 48-year-old man presented with transient motor aphasia and diplopia. Magnetic resonance imaging showed a cystic lesion occupying the left frontal and temporal convexity with midline shift and uncal herniation. Cyst resection was performed, and cyst contents with mucous-like components were aspirated. Histopathological examination showed an endodermal cyst. The patient showed no neurological deficits immediately after surgery but developed tonic-clonic seizures 9 h after surgery. Sedation and intubation were required to control the seizures. After administering multiple antiepileptic drugs, he was extubated on the 5^th day after surgery. He was discharged home in a month with mild impairment in dexterity of his right hand.

Conclusions: Surgical intervention for endodermal cysts can be complicated by postoperative seizures caused by chemical irritation of brain cortex due to spillage of cyst contents. It is important to irrigate the cyst wall very well intraoperatively and pay attention not to spill the cyst fluid to unaffected locations. Preoperative administration of antiepileptic drugs should also be considered if endodermal cysts, not simple arachnoid cysts, are suspected preoperatively.

Keywords: Endodermal cyst; Neurenteric cyst; Postoperative seizure; Status epilepticus.

Figure 1:

Preoperative magnetic resonance imaging showing T1- weighted (a), T2-weighted (b), and fluid-attenuated inversion recovery (c) images. The cyst content demonstrates slightly higher intensity than regular cerebrospinal fluid on fluid-attenuated inversion recovery images, containing a mucous-like nodule with isointensity on T1WI and mild high intensity on T2WI. Uncal herniation is observed at the level of the mesencephalon (d).

Figure 2:

Intraoperative presentation of the cyst. The cyst is covered by a thin whitish membrane and contains white turbid fluid.

Figure 3:

Postoperative course is organized as a timeline. The patient experienced a tonic-clonic seizure 9 h after surgery. Lumbar puncture and electroencephalogram were performed on postoperative day 1. The seizure was finally controlled with levetiracetam 4000 mg, Fosphenytoin 7.5 mg/kg, Lacosamide 200 mg, and propofol 0.3 mg/kg/h.

Figure 4:

(a and b) Postoperative magnetic resonance imaging shows cyst shrinkage and disappearance of the mass effect.

Figure 5:

Histopathological features of the cyst wall. Hematoxylin and eosin staining shows pseudostratified ciliated columnar epithelium with a basement membrane (a). The presence of goblet cells is shown by periodic acid-Schiff staining (b). Carcinoembryonic antigen is also positive in the cytoplasm in a few epithelial cells, suggesting carcinoembryonic antigen secretory capacity (c).