Adenocarcinoma arising in an ectopic enterogenous cyst: A rare case report and review of literature

Enterogenous cyst (EC) is a rare congenital lesion generally located in the central nervous system, such as in the cerebral hemispheres, posterior fossa, or spinal canal. They are usually benign lesions, and malignant transformation is rare. A 42-year-old woman felt an obvious pain in the lump and went to a local hospital for local lumpectomy. After 7 months, she again felt pain in the buttocks and difficulty in urinating and defecation. The computed tomography (CT) scan showed a mass in the pelvis. Sacrococcygeal cyst excision was performed 10 days later, and postoperative pathology showed epidermoid cyst. Shortly after, the patient recovered and was discharged from the hospital; the pain in the buttocks continued to recur. Puncture and drainage were performed five times. Later, the patient went to our hospital for treatment, and pelvic MRI showed multiple abnormal signal shadows in the presacral and sacrococcygeal regions, some of which were considered abscesses, and some were cystic lesions. She underwent tumor resection and was diagnosed with EC with locally moderately differentiated adenocarcinoma. Four months later, the patient's symptoms of swelling and pain recurred. MRI examination showed multiple high-signal T2 shadows in the anterior sacral and subcutaneous tissues of the buttocks, and enhanced scan showed partial marginal enhancement. After assessment, the patient was given a radiation dose of 60 Gy/25F. ECs in the anterior sacral and soft tissue of the buttocks are very rare, and the case of carcinomatous transformation has never been reported. Therefore, we discussed the clinicopathological features of ectopic ECs and reviewed the literature.

Elucidating the multiple genetic alterations involved in the malignant transformation of a KRAS mutant neurenteric cyst. A case report

Neurenteric cyst (NC) shows benign histopathology and rarely demonstrate malignant transformation. We herein describe a case of NC that exhibited malignant transformation. A 65-year-old female presented with gait disturbance due to compression by a cystic mass on the dorsal surface of the medulla oblongata. Partial resection was performed twice, leading to improvement of her symptoms. Two years after the second surgery, gadolinium-perfused T1-weighted magnetic resonance imaging revealed an invasive lesion with contrast enhancement at the trigone of the left lateral ventricle for which partial resection followed by radiotherapy was performed. However, mass regrowth was observed, with the patient eventually succumbing to her disease 11 months after her third surgery. Histopathological analyses of the first and second surgical specimens identified pseudostratified cuboidal epithelial cells, with no nuclear or cellular atypia resembling gastrointestinal mucosa, lining the inner surface of the cystic wall. Based on these findings the lesion was diagnosed as NC. The third surgical specimen exhibited apparent malignant features of the epithelial cells with elongated and hyperchromatic nuclei, several mitotic figures, small necrotic foci, and a patternless or sheet-like arrangement. Based on these findings, the lesion was diagnosed as NC with malignant transformation. Next-generation sequencing revealed KRAS p.G12D mutation in all specimens. Additionally, the third surgical specimen harbored the following 12 de novo gene alterations: ARID1A loss, BAP1 p.F170L, CDKN1B loss, CDKN2A loss, CDKN2B loss, FLCN loss, PTCH1 loss, PTEN loss, PTPRD loss, SUFU loss, TP53 loss, and TSC1 loss. The aforementioned results suggest that KRAS mutation is associated with the development of the NC, and that the additional gene alterations contribute to malignant transformation of the NC.

Nonneoplastic and noninfective cysts of the central nervous system: A histopathological study

Nonneoplastic epithelial cysts involving the central nervous system are diverse and are predominantly developmental in origin. This study represents a surgical series describing the histopathological features of 507 such epithelial cysts with clinical and imaging correlation. Age at surgery ranged from 7 months to 72 years (mean: 33 years) affecting 246 male and 261 female patients. Colloid cyst was the most frequently resected cyst, followed by epidermoid cyst, arachnoid cyst, Rathke cleft cyst, dermoid cyst, neurenteric cyst, Tarlov cyst, and choroid plexus cyst. Diagnosis was based on the location of the cysts and the nature of the lining epithelium. Rathke cleft cyst showed the highest propensity for squamous metaplasia, significant inflammation, and xanthogranulomatous reaction. Ulceration of lining epithelium and calcification were most frequent in dermoid cyst. Radiopathological concordance was maximal for colloid cyst, followed by epidermoid and arachnoid cysts. Epidermoid and dermoid cysts exhibited the highest propensity for local tumor progression, followed by Rathke cleft cyst.

Pediatric intracranial neurenteric cyst of the oculomotor nerve: a case-based review

BACKGROUND

Neurenteric cysts (NECs) of the central nervous system (CNS) are uncommon congenital entities arising from embryonal elements. Intracranial NECs in the pediatric population are rare.

METHODS

The authors describe the presentation, radiographic imaging, and pathologic findings of an 11-year-old boy with a right oculomotor nerve NEC. A literature review was performed to identify additional cases of pediatric intracranial NECs published in the English language, over the past 30 years (1990-2020). The authors discuss the presentation, investigations, management, and prognosis of this interesting entity.

RESULTS

We describe an 11-year-old boy who presented to neurosurgical attention with disconjugate gaze, anisocoria, and ptosis. Magnetic resonance imaging (MRI) demonstrated a lobulated, cystic, and peripherally enhancing mass involving the right oculomotor nerve. The patient underwent pterional craniotomy for drainage of the cyst and subtotal resection of the cyst wall. The tan-colored mass was displacing the basilar artery, compressing the cerebral peduncle, and adherent to the inferior surface of the tentorium. The lesion was within the oculomotor nerve and splitting the fibers, and the cystic contents were thick and mucinous. Histopathological examination of the specimen demonstrated a thin fibrous cyst wall with scattered inflammatory cells and lined by simple columnar epithelium containing mucin. The lining cells were immunoreactive with epithelial membrane antigen (EMA) and pan-keratin AE1/AE3. The diagnosis of a NEC was rendered. A comprehensive literature review of pediatric intracranial NECs yielded 46 additional lesions published in the literature, involving the skull base, posterior fossa, cerebral convexity, and cranial nerves. NECs present with local mass effect and less commonly, with aseptic meningitis or intracystic hemorrhage. Maximal safe GTR remains the mainstay management, although cyst drainage and marsupialization, cyst shunting, and fenestration of cystic contents into the ventricle or basal cisterns have been reported with variable success.

CONCLUSION

CNS NECs are rare congenital entities; although they occur less frequently in the intracranial components compared to the spine, their diagnosis and management should be considered for intracranial cystic lesions. Maximal safe GTR is the mainstay treatment and frequently yields favorable outcomes.

Endodermal Cysts of the Central Nervous System: Review of the Literature and a Case Report

Context

Endodermal cysts are rare benign developmental cysts lined by mucin-secreting and/or ciliated, cuboidal, or columnar epithelium of probably endodermal origin.

Aims

Endodermal cysts are rarely intracranial, frequently located in the posterior fossa. Supratentorial location is the most infrequent and only few cases are reported in the literature, included our case.

Settings and Design

The authors report a case of intracranial supratentorial endodermal cyst with a review of the literature.

Subjects and Methods

A 40-year-old woman was admitted to our department because of progressive gait disorder for 3 months due to right brachial and crural motor deficit associated to right crural sensory disorder (tactile hypesthesia) and right Babinski response at neurological examination due to an endodermal cyst located in the left frontoparietal convexity.

Discussion

Total resection of endodermal cysts is recommended, despite their location and adhesion to the surrounding structures, due to its high risk of recurrence. Fenestration of the cystic content into the subarachnoid cistern may cause obstructive hydrocephalus or chemical meningism.

Results

Although rare, surgeons should be aware that these lesions must be differentiated clinically, radiologically, and histologically from other supratentorial cystic lesions.

Therapeutic Strategies and Prognostic Factors Based on 121 Spinal Neurenteric Cysts

BACKGROUND

Limited data existed to guide the management of intraspinal neurenteric cysts (ISNECs).

OBJECTIVE

To evaluate the risk factors for progression-free survival (PFS), elucidate the radiological features of ISNECs, and propose a treatment protocol.

METHODS

From 2003 to 2015, 121 patients with pathologically confirmed ISNECs treated at our institute were included in this study. Pertinent risk factors were evaluated.

RESULTS

Gross total resection (GTR) was achieved in 55 (44.6%) patients; 106 (87.6%), 12 (9.9%), and 3 (2.5%) ISNECs were classified as Wilkins A, B, and C, respectively. After a median follow-up duration of 64.2 mo, recurrence occurred in 25 (22.7%) patients, with a median PFS time of 43.1 mo. The actuarial PFS rates at 5 and 10 yr were 73.2% and 66.2%, respectively. The actuarial overall survival rates at 5 and 10 yr were 100% and 97.6%, respectively. Non-GTR (hazard ratio [HR], 5.836; 95% confidence interval [CI], 1.698-20.058; P = .005), Wilkins B/C (HR, 3.129; 95% CI, 1.009-9.702; P = .048), and a history of surgical resection (HR, 3.690; 95% CI, 1.536-8.864; P = .004) were adverse factors.

CONCLUSION

GTR and Wilkins A were favorable factors for PFS. If tolerable, GTR alone was advocated as an optimal treatment. Because of the benign nature and favorable prognosis, non-GTR was an alternative if GTR failed. Close follow-up was needed because of the recurrent tendency of ISNEC. Future study with a large cohort is necessary to verify our findings.

Single-Center Clinical Characteristics and Treatment Experience of Foramen Magnum Neurenteric Cyst: Report of 6 Cases and Brief Review of the Literature

OBJECTIVE

To retrospectively analyze the clinical data of 6 patients with foramen magnum (FM) neurenteric (NE) cysts, and summarize the clinical characteristics and treatment experience for this rare disease in our single center.

METHODS

Between January 2011 and December 2015, 6 patients with FM NE cyst were surgically treated at Xuan Wu Hospital of Capital Medical University. We summarize the treatment experience of these patients through a retrospective review of the clinical information, imaging features, surgical details, and follow-up outcomes.

RESULTS

All 6 patients were female, ranging in age from 15 to 54 years (mean age, 36.8 ± 12.9 years). Occipital headache along with cranial nerve injury were the most common symptoms. Preoperative brain magnetic resonance imaging identified all lesions in the FM region, with an oblong or lobulated shape. The surgical approach was far lateral in 4 patients and suboccipital midline in 2 patients. Total lesion removal was completed in 4 patients, and subtotal excision was performed in the other 2 patients, in whom the cyst wall was intensely adherent to surrounding structures. In all 6 patients, the preoperative symptoms were significantly relieved after surgery. No recurrence was seen after a mean follow-up of 27.3 months (range, 3-70 months).

CONCLUSIONS

Our present study identified a female predominance among patients with intracranial FM NE cyst. Surgical excision is the optimum treatment strategy for this rare disease. Our findings indicate that subtotal removal of an FM NE cyst may be associated with favorable outcomes, but strict long-term follow up is needed.

Mucinous adenocarcinoma arising from a residual supratentorial neurenteric cyst and expressing mutated KRAS: a case report

Malignant transformation of intracranial neurenteric cysts (NCs) has been reported in only 7 cases, but the molecular characteristics leading to malignant transformation remain unclear. A 61-year-old woman presented with headache and dizziness. Imaging revealed a 10-cm, extra-axial cystic mass in both middle fossae. A partial resection was performed, and the residual mass size gradually decreased. She had repeated ventriculoperitoneal shunts to relieve symptoms of hydrocephalus. Eight years later, follow-up images revealed marked enlargement of the mass and a newly developed lesion. After a second partial resection, a mucinous adenocarcinoma infiltrating the brain was identified. Transitions from benign-looking cuboidal cells to dysplastic cells were observed. A KRAS mutation, which might be associated with malignant NC transformation and was not present in the initial specimen, was identified in the adenocarcinoma. In conclusion, KRAS-mutant mucinous adenocarcinoma may arise in a longstanding residual NC after partial resection.

Recurrent intracranial neurenteric cyst with malignant transformation: A case report and literature review

Neurenteric cysts (NCs) are uncommon congenital cystic lesions. Malignantly transformed NCs are extremely rare. The present study reports the case of a recurrent foramen magnum NC with a malignant transformation and reviews 8 previously reported cases. A 58-year-old woman with a 5-month history of occasional headaches, dizziness and vomiting presented to the Beijing Tiantan Hospital (Beijing, China) with palsy of the left cranial IX and X nerves, decreased sensation in the limbs on the right side and an ataxic gait. Magnetic resonance imaging (MRI) scans revealed a cystic mass in the left side of the foramen magnum, positioned anteriolaterally to the medulla oblongata. Surgery using a left suboccipital retrosigmoid approach was performed. The lesion was partially resected and was histopathologically diagnosed as an NC with focal hyperplasia of the epithelial cells. Additional MRI scans that were performed 25 months later revealed a solid lesion posterior to the medullar oblongata. Therefore, surgery using a suboccipital midline approach was performed. The solid lesion was sub-totally removed and was histopathologically diagnosed as a well-differentiated papillary adenocarcinoma. At 1 month post-surgery, the patient's condition worsened, eventually resulting in mortality due to respiratory failure. Based on the findings of the present case and previous literature, strict criteria for malignant-transformed NCs were created. The location distribution of malignant-transformed NCs does not coincide with the location distribution of all NCs, and malignantly transformed NCs usually occur in adult patients and present as atypical radiological features. Surgery is the optimal treatment for malignantly transformed NCs, and the effectiveness of adjuvant therapy requires additional studies.

Cerebellar Enterogenous Cyst with Atypical Appearance and Pathological Findings

BACKGROUND

Intracranial enterogenous cysts are rare and occur mainly in the posterior fossa. These cysts are usually extra-axial, midline, anterior to the brainstem, or at the cerebellopontine angle. Intracranial intra-axial enterogenous cysts are extremely rare. We report a case of an intra-axial cerebellar enterogenous cyst in which diagnosis was difficult because the lesion resembled an arachnoid cyst in appearance and showed atypical pathologic findings.

CASE DESCRIPTION

A 69-year-old woman had a 2-year history of progressive headache, giddiness, and unsteadiness of gait. Magnetic resonance imaging showed a cystic lesion with isointensity to cerebrospinal fluid in the left cerebellar hemisphere, reaching into the fourth ventricle. The patient underwent fenestration of the cyst and creation of a communication between the fourth ventricle and cyst because the tight attachment of the cyst wall to the cerebellum prevented total removal of the cyst. Although pathologic examinations did not show findings typical of enterogenous cyst, the diagnosis was finally made based on the presence of basement membrane and immunohistochemical results.

CONCLUSION

The diagnosis of enterogenous cyst is based mainly on histologic findings, because characteristic findings on neuroimaging have not been defined. Although total resection of enterogenous cysts is recommended in general, partial resection while ensuring the cyst communicates adequately with the surrounding cerebrospinal fluid space with or without a shunt procedure may be useful if the cyst is adherent to surrounding neurovascular structures.

Malignant Transformation of a Neurenteric Cyst in the Posterior Fossa Presenting with Intracranial Metastasis: A Case Report and Literature Review

Intracranial neurenteric cysts are relatively rare and almost exclusively benign. Here we present a case of an intracranial neurenteric cyst that was histologically benign in the first surgery and later demonstrated significant growth and intracranial metastasis with malignant transformation. A 47-year-old woman presented with a headache, which had gradually worsened over 1 year. Initial magnetic resonance (MR) images revealed a solitary cystic lesion in the left cerebellopontine angle with significant mass effect. Subtotal resection leaving a small mass strongly adhered to the brainstem was achieved. Histopathological diagnosis was neurenteric cyst with no malignant features. This lesion recurred 4 years after the first surgery in the form of a cystic mass adjacent to the brainstem. In addition, histopathological examination of a specimen from the second surgery revealed malignant transformation. The patient declined to undergo radiation therapy and was conservatively managed. Three years after the second surgery, MR imaging showed recurrence of the solid mass. Although the patient had been treated with subtotal resection and radiation therapy, she died with metastatic masses in the right frontal lobe and cervical cord. A specimen from the third surgery revealed diffuse malignant features similar to mucinous adenocarcinoma. Our case and literature review indicate that, although rare, malignant transformation can occur particularly among intracranial neurentreric cysts. This finding suggests the importance of long-term follow-up for subtotally or partially resected intracranial neurenteric cysts.

Mucinous adenocarcinoma arising from supratentorial intramedullary neuroenteric cyst with broncho-pulmonary differentiation

Neuroenteric cysts are benign intradural endoderm cysts lined by gastrointestinal (GI) or tracheobronchial epithelial cells. Their malignant transformation is extremely rare and only six cases have been reported. In these cases, tissue lineage of the cystic endoderm cells giving rise to carcinoma was not clearly identified either as respiratory or as GI type. Herein, we report a case of mucinous adenocarcinoma arising from the neuroenteric cyst with broncho-pulmonary differentiation in the right cerebral hemisphere of a Japanese woman in her late 50s. The cyst wall was entirely lined by the following respiratory epithelial components: stratified bronchial ciliated columnar epithelium with basal cells positive for CK5 and p63, terminal bronchiolar Clara cells positive for thyroid transcription factor (TTF)-1, surfactant B and negative for surfactant C, type I pneumocytes positive for TTF-1, negative for surfactant B and C, and type II pneumocytes positive for TTF-1 and surfactant B and C. In addition, nests of hyperplastic single layered mucinous epithelial cells with bronchial goblet cell phenotype were also demonstrated, and histologic features were almost the same as the pulmonary type I congenital adenomatoid malformation (CCAM) with mucinous epithelial proliferation. The mucinous epithelial nests of type I CCAM are liable to develop mucinous adenocarcinoma and frequently accompany K-ras mutation and expression of p16. However, K-ras mutation and p-16 expression were not detected in this case.

Supratentorial neurenteric cyst mimicking hydatid cyst: A case report and literature review

Neurenteric (NE) cysts are uncommon congenital cysts of endodermal origin. These cysts are commonly encountered in the posterior fossa surrounding the brain stem structures. We present a case of pathologically proven supratentorial NE cyst that mimicked a hydatid cyst in its clinical presentation and imaging appearance. Including this pathology in the differential diagnosis of supratentorial cystic lesions is important due to the differences in medical and surgical management.

Microsurgical excision of the craniocervical neurenteric cysts by the far-lateral transcondylar approach: case report and review of the literature

Neurenteric cysts in the anterior craniocervical junction (CCJ) region can be found in extremely rare cases. We report one case with craniocervical neurenteric cyst that was excised by the far-lateral transcondylar (FLT) approach. A 43-year-old man presented with a history of recurrent episodes of mild neck pain and dysesthesia in his bilateral hands of 2 years' duration with rapid deterioration 3 weeks prior to admission. Magnetic resonance imaging (MRI) of the CCJ region revealed a well-defined intradural cystic lesion located ventral from the pontomedullary junction to C1 vertebra with medulla and C1 cord compression. This patient underwent total excision of the lesion via the FLT approach without any postoperative neurological deficits, and the histopathologic diagnosis was neurenteric cyst. Follow-up MRI has revealed no evidence of recurrence. The clinical features, imaging studies, and surgical approach options involved in resecting craniocervical neurenteric cysts are discussed, along with a review of the literature.

Endoscopic transsphenoidal, transclival resection of an enterogenous cyst located ventral to the brainstem: case report

BACKGROUND AND IMPORTANCE

Enterogenous cysts are rare tumors found most commonly in the spine, but they have also been reported intracranially. Cases of enterogenous cysts located within the posterior fossa have traditionally been resected via difficult craniotomies that require prolonged retraction and risk injury to cranial nerves. We describe a method for resection of an enterogenous cyst located anterior to the brainstem via the endoscopic transsphenoidal approach.

CLINICAL PRESENTATION

A 37-year-old man was found to have a 2-cm mass anterior to the brainstem during routine screening after a trauma. The mass was located within the prepontine cistern, enhanced with gadolinium contrast, and showed no restrictive diffusion. This lesion was most consistent with an enterogenous cyst. A minimally invasive endoscopic endonasal transsphenoidal transclival approach was performed for gross total resection of the tumor.

CONCLUSION

We discuss the endoscopic transsphenoidal approach used for the resection of an enterogenous cyst in the posterior fossa anterior to the brainstem. The transsphenoidal approach provides direct access to lesions in this location using a minimally invasive technique while avoiding excessive brain retraction or injury to cranial nerves. In addition, we provide an updated review of the literature for enterogenous cysts located within the posterior fossa.

Neurenteric cyst of the lower clivus

OBJECTIVE

Neurenteric cysts (NCs) typically arise as benign ventral intradural extramedullary developmental malformations of the spine which contain heterotopic epithelium resembling the intestinal or respiratory tracts. Intracerebral NCs are extremely rare, though the frequency of symptomatic reports and incidental findings is increasing, perhaps because of advances in neuroimaging. Recognition of the unique radiographic and histopathologic features of this entity is of growing importance in the treatment of cysts of the neural axis. We present an unusual case of an NC arising at the lower clivus.

CLINICAL PRESENTATION

A 58-year-old man presented with occipitalgia, diplopia, a bilateral hearing deficit, and mild dysphagia. Computed tomography and magnetic resonance imaging demonstrated a 5 x 2 x 3-cm extra-axial cystic midline mass anterior to the brainstem at the lower clivus with posterior cyst wall enhancement.

INTERVENTION

The patient underwent a left lateral suboccipital total macroscopic resection of the lesion. Microscopic examination and histopathologic findings were consistent with a diagnosis of NC.

CONCLUSION

We describe the clinical presentation, imaging, and histopathologic characteristics, and discuss the diagnosis and surgical treatment of this rare lesion and related pathologic entities. Because of the remote possibility of delayed recurrence, even in cases of apparent total cyst wall removal, long-term serial imaging and a consideration of reoperation for recurrences is advisable.