Spinal endodermal cyst resembling an arachnoid cyst in appearance: Pitfalls in intraoperative diagnosis of cystic lesions

Abstract

Background:Surgical treatment of endodermal cysts requires total removal of the cyst wall during the first operation to prevent recurrence. Therefore, intraoperative pathological diagnosis plays an important role in determining the optimal surgical strategy. We present a rare case of a spinal endodermal cyst and discuss its diagnostic difficulty during the intraoperative pathological examination.Case Description:An 18-year-old male presented with progressive paraparesis and precordial oppression. Magnetic resonance (MR) imaging revealed an intradural extramedullary cystic mass having the same signal intensity as cerebrospinal fluid (CSF) without gadolinium enhancement at the T1-T2 level. The preoperative diagnosis was an endodermal or arachnoid cyst. The patient underwent surgery. An intraoperative frozen section showed a cyst wall consisting of loose, thin, fibrous tissue intermittently covered by flattened epithelium. The diagnosis was an arachnoid cyst. Accordingly, partial resection of the cyst wall was performed to create CSF communication between the cyst and subarachnoid space. However, the postoperative pathological diagnosis from permanent sections was an endodermal cyst, which was lined with ciliated columnar epithelium that was immunopositive for cytokeratin and epithelial membrane antigen. Subsequent paraffin embedding and immunostaining of the intraoperative frozen sample also confirmed patchy cytokeratin expression by all flattened epithelial cells. The patient's cyst had refilled 10 months after surgery, and he subsequently underwent fenestration of the cyst wall and placement of a cyst-subarachnoid shunt.Conclusion:Examination of multiple samples from multiple sites or intraoperative immunostaining of frozen sections is recommended for accurate intraoperative diagnosis of endodermal cysts.

Cervical myelopathy due to an endodermal intraspinal cyst in a two-year-old child: a case report

“…Besides MRI, our patients have also done other examinations such as complete blood count, chest, cervical and abdominal x-ray with no abnormality signs. 10, 11 In our case, there was no corresponding findings between MRI results and histopathological result. The MRI examinations found the cause of the cervical myelopathy is an intradural extramedullary tumor that tends to be a schwannoma, while the histopathological result found a benign intraspinal cyst.…”

“…They are characterized histologically by the cyst wall was composed of a loose, thin, fibrous membrane containing melanocytes and was intermittently lined with flattened or partially cuboidal epithelial cells. 11 Although a congenital lesion, an endodermal cyst is frequently diagnosed in adulthood, usually during the third decade. However, it can present at any age.…”

“…The spinal endodermal cysts may be associated with various other congenital spinal anomalies. 11 The other type of cyst, synovial cyst, develops from a facet joint, is usually on the posterolateral aspect of the dural sac, contains mucinous fluid, and has synovial lining cells in its wall. An intraspinal synovial cyst can be differentiated from a disk cyst by location.…”

Giant petroclival endodermal cyst with xanthogranulomatous changes

“…9,11,12 Therefore, a cystic tumor was included in the differential diagnosis because our case showed bone destruction and rim enhancement, which are rare in intracranial cysts. 7,9,12 A thin peripheral rim of enhancement could be attributed to inflammatory change or squamous metaplasia of the cyst wall.…”

“…6,7,9,[11][12][13][14] In general, the absence of contrast enhancement of the cyst wall and of bone destruction is useful for distinguishing endodermal cysts from other cystic lesions such as cystic schwannoma and cystic meningiomas. 9,11,12 Therefore, a cystic tumor was included in the differential diagnosis because our case showed bone destruction and rim enhancement, which are rare in intracranial cysts. 7,9,12 A thin peripheral rim of enhancement could be attributed to inflammatory change or squamous metaplasia of the cyst wall.…”