Neurology India Medknow Publications on behalf of the Neurological Society of India ISSN: 0028-3886 EISSN: 1998-4022 Vol. 58, Num. 5, 2010, pp. 774-777

Neurology India, Vol. 58, No. 5, September-October, 2010, pp. 774-777

Case Report

Supratentorial enterogenous cyst: A report of two cases and review of literature

Ganesh Krishnamurthy¹, VR Roopesh Kumar¹, R Rajeswaran², Shalinee Rao³

¹ Department of Neurosurgery, Jawaharlal Institute of Postgraduate Medical Education and Research (JIPMER), Pondicherry, India
² Department of Radiodiagnosis, Sri Ramachandra Medical College, Porur, Chennai, India
³ Department of Pathology, Sri Ramachandra Medical College, Porur, Chennai, India

Correspondence Address:
V R Roopesh Kumar
Department of Neurosurgery, Jawaharlal Institute of Postgraduate Medical Education and Research, Pondicherry - 605 006
India
roops1975@rediffmail.com

Date of Acceptance: 30-Jul-2010

Code Number: ni10212

PMID: 21045510

DOI: 10.4103/0028-3886.72200

Abstract

Keywords: Craniospinal dissemination, endodermal, immunohistochemistry, intractable seizures, non-enhancing cyst, supratentorial

Introduction

Enterogenous cysts, also known as neurenteric cysts, are rare developmental anomalies presumably derived from endodermal epithelium. ^[1] They are commonly encountered in the cervicodorsal spine. Intracranial occurrence is distinctly rare, and often located in the infratentorial compartment. ^[2] Fewer than 16 cases in the supratentorial compartment location have been documented till date ^{[3],[4],[5],[6]} [Table - 1]. We report two patients with supratentorial enterogenous cyst with special emphasis on management strategies.

Case Reports

Case 1

A 32-year-old man presented with progressive left hemiparesis and features of raised intracranial pressure of one month duration. Computerized tomography (CT) and magnetic resonance imaging (MRI) of brain [Figure - 1] revealed a large right frontoparietal non-enhancing cystic lesion with considerable mass effect. At operation, cystic lesion containing yellowish white milky fluid was evacuated. In the immediate postoperative period, the patient had refractory seizures, which were controlled with multiple antiepileptic drugs. At one year follow-up, the patient was asymptomatic and a repeat MRI brain showed no recurrence.

Case 2

A 44-year-old woman presented with features of raised intracranial pressure of two months duration without neurological deficits. CT and MRI of brain [Figure - 2] revealed a large left frontoparietal non-enhancing cystic lesion with mass effect. Peroperative findings were similar to those seen in the case 1. Her postoperative period was uneventful, and was relieved of raised intracranial pressure. In both the patients, preoperative diagnosis of arachnoid cyst was entertained considering the MRI picture.

Histopathology

In both the cases, light microscopy showed cuboidal-to-columnar lining with focal pseudo-stratification and mucus containing goblet cells [Figure - 3] and [Figure - 4]. Immunohistochemistry showed positive staining of the cyst wall epithelium with cytokeratin, EMA, CEA; and was negative for GFAP, S-100 protein and Ki-67 (MIB-1). These findings support the endodermal nature of the cyst and fall into group B type of cyst according to Wilkins and Odoms criteria. Biochemical analysis of the cyst fluid in Case 2 was: pH- 6.0, sugar of 12 mg/dL, proteins of 0.8 g/dL, chloride of 140 mg/dL, amylase of 3,252 U/L; and LDH of 28 μ/L.

Discussion

Supratentorial enterogenous cysts are thought to originate from remnants of endodermally derived Seesel's pouch, a transient diverticulum of the cranial end of embryonic foregut. This diverticulum arises caudal to Rathke's pouch and rostro-dorsal to oropharyngeal membrane and can give rise to enterogenous cyst, Rathke's cleft cyst or colloid cyst, depending on the location of the remnants. ^[7] Although difficult to explain, multiple enterogenous cysts in both supratentorial and infratentorial compartments are thought to arise either as a result of multifocality or are iatrogenic as a consequence of intraoperative dissemination. ^[8] Enterogenous cyst contains turbid gelatinous fluid with variable sugar and protein levels with acidic or alkaline pH, depending on the predominance of lining epithelium (gastric or bronchial, respectively). The lining membrane will show combined immunoreactivity for EMA, CEA and cytokeratin with absent reactivity for glioneuronal markers like GFAP, S-100 and NSE, suggesting the cyst to be an endodermal derivative. Additionally, cytokeratin 7 is a marker of respiratory epithelium; and cytokeratin 20, of gastrointestinal epithelium. ^[5] Cystic metastasis from primary adenocarcinoma resembles enterogenous cyst but can be differentiated by the cytological atypia. It is of utmost importance to distinguish a primary adenocarcinoma arising in enterogenous cyst from a metastatic carcinoma. Adenocarcinoma but not squamous cell carcinoma can occur in longstanding enterogenous cyst. ^[9]

Patients with supratentorial enterogenous cyst usually present at a later age, third and fourth decades, compared to the cyst in the spinal location. ^[1] The radiological features are nonspecific, and it is difficult to differentiate enterogenous cysts from other cystic lesions such as arachnoid cyst, epidermoid or glioependymal cyst. ^[1],[2] Surgical excision is the preferred treatment for supratentorial enterogenous cysts, and complete excision of the cyst wall produces excellent results. ^{[1],[2],[3],[4],[10],[11]} However, it is debatable whether complete removal of cyst wall is necessary to prevent recurrence. Though incomplete excision of the cyst wall can produce excellent results, delayed recurrence may occur, as the residual cyst wall has proliferatory and secretory potential. Additionally, symptomatic expansion of enterogenous cyst may result from cerebrospinal fluid (CSF) accumulation in the cyst attributable to osmotic effect after scarring and resealing of fenestrations in the cyst wall. Further, partial excision results in excessive scarring, which may complicate excision of recurrent cyst. ^[1],[11] However, if the cyst wall is adherent to pia of eloquent cortex or the bridging veins, it is wise to leave behind a small portion of the cyst wall to prevent unacceptable postoperative morbidity. Aspiration alone invariably results in recurrence and does not aid in establishing the histopathological diagnosis.

During surgery, extreme caution has to be exercised to prevent spillage of the cyst contents, as there are documented cases of extensive craniospinal seedling following surgical excision of enterogenous cyst. ^[8] More importantly, cyst fluid containing digestive enzymes of gastric origin will irritate the cortex, resulting in postoperative refractory seizures, as observed in one of our patients ^[11] This complication is not seen in infratentorial or spinal location. Hence it is essential to thoroughly irrigate the cyst cavity following evacuation of the contents before contemplating excision of the inner cyst wall from the underlying pia. We feel that post operative seizures due to spillage of the cyst content can be prevented by adequate preoperative administration of corticosteroids and by avoiding spillage of cyst contents over adjacent pia.

Conclusion

Cysts of endothelial origin should be considered in any adult patient with a large non-enhancing cystic lesion in the supratentorial compartment. The ideal treatment is total excision of the cyst wall. Adequate care should be taken peroperatively to prevent spillage of cyst contents, thereby avoiding dissemination and postoperative refractory seizures. Recurrent seizures in the immediate postoperative period should be anticipated and can be prevented by peroperative administration of corticosteroid and prophylactic anticonvulsants. Long-term outcome is excellent if total excision of the cyst wall could be achieved.

References

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