Choroidal epithelial cyst of the cerebral hemisphere. An immunohistochemical study

SUPRATENTORIAL, EXTRAVENTRICULAR CHOROID PLEXUS CARCINOMA IN AN ADULT

OBJECTIVE

Choroid plexus carcinoma (CPCa) is an uncommon tumor rarely occurring in patients older than 2 years of age. The case reported herein represents the first documented example of a primary supratentorial, extraventricular CPCa in an adult. The scant literature regarding this topic is reviewed.

CLINICAL PRESENTATION

A 68-year-old woman presented with transient expressive aphasia. Magnetic resonance imaging demonstrated an avidly enhancing, left temporal, extra-axial mass with associated parenchymal cysts.

INTERVENTION

The tumor was gross-totally removed via a frontotemporal craniotomy. A diagnosis of CPCa was made on histological, immunohistochemical, and ultrastructural grounds. Postoperatively, the patient was treated by local radiotherapy and temozolomide. A magnetic resonance imaging scan 44 months after surgery showed no evidence of residual or recurrent tumor.

CONCLUSION

CPCa infrequently affects adults. Only rarely does it present as a supratentorial, extraventricular mass. Resection is the mainstay of therapy. Adjuvant radiation and chemotherapy are rational treatment options.

Benign cysts in the central nervous system: Neuropathological observations of the cyst walls

A diverse variety of benign cysts exist in the CNS. Advances in diagnostic radiology have facilitated diagnoses and surgical intervention in many patients with CNS cysts. However, a fundamental understanding of the pathological features of these lesions is clinically vital. From an etiological point of view, the cysts can be divided into two groups. The first includes lesions that arise from within the CNS and may be static structures such as cavities arising from infarcts and other destructive processes while other lesions such as arachnoid cysts, ependymal cysts, cystic hemangioblastoma, cystic cerebellar astrocytoma and infectious processes, are progressive. The second group of cysts arise from the intrusion of non-nervous system tissue into the neuroaxis and are usually midline. They are frequently expanding congenital lesions although some become symptomatic only in adults. Examples include teratomas, dermoid cysts, epidermoid cysts, craniopharyngiomas, Rathke's cleft cysts, and other epithelial cysts presumably derived from the upper respiratory or intestinal tract. Chick embryos exposed to lead have been used as a model of cyst formation.

Choroid plexus carcinoma presenting as an intraparenchymal mass

A 6-year-old girl with a history of a nondisplaced skull fracture diagnosed with computerized tomography (CT) scanning 3 years previously presented with a 6-week history of headaches and decreased use of her right side. On admission CT scans, a large cystic mass was identified in the left frontal lobe region of the brain. A connection between the mass and the ventricular system was not seen on radiological examination or during surgery. Gross-total resection of the mass was achieved. The histological and immunohistochemical findings in the resected tissue confirmed a diagnosis of choroid plexus carcinoma (ChPC). This is the first reported case of a ChPC arising in an extraventricular location not associated with the choroid plexus.

Large ependymal cyst of the cerebello-pontine angle in a child

Most ependymal cysts occur intracerebrally, with a few cases situated in the subarachnoid space. The cerebellopontine angle is a common site for arachnoid cysts, but a very rare site for ependymal cysts. A case is described here of a large ependymal cyst in the cerebellopontine angle. A 12-year-old girl with left hearing disturbance was admitted. CT and MRI revealed a cystic tumor in the left cerebellopontine angle. At operation, we obtained a discrete thin-walled cyst which had arisen from a continuation of the choroid plexus of the lateral foramen of Luschka, which had no connection with the arachnoid. The cyst proved to be an ependymal cyst.

Colloid cyst of the third ventricle. A comparative immunohistochemical study of neuraxis cysts and choroid plexus epithelium

In an effort to shed light upon the nature of the colloid cyst, the immunohistochemical properties of 21 examples of this lesion were compared with those of other neuraxial cysts and choroid plexus epithelium. The neuraxial cysts included the following: eight Rathke's cleft cysts, 25 pituitaries containing follicular cysts of the pars intermedia, and four enterogenous cysts. Fifteen examples of normal choroid plexus and 12 choroid plexus papillomas were studied as well. These lesions were examined for localization of the following antigens: cytokeratins, epithelial membrane antigen, secretory component, carcinoembryonic antigen, prealbumin, vimentin, glial fibrillary acidic protein (GFAP), S-100 protein, neuron-specific enolase, 68-kD neurofilament protein, chromogranin, serotonin, and lysozyme, and with Leu-7 monoclonal antibodies. Five colloid cysts were immunostained with monoclonal antibodies that were specific for Clara-cell antigens and surfactant, respectively. Sugar moieties were localized using Ulex europaeus I, and Ricinus communis agglutinin I lectins. All Rathke's cleft cysts and follicular cysts of the pars intermedia as well as three selected colloid cysts were examined for pituitary hormones. The epithelial cells of colloid and enterogenous cysts, as well as those lining follicular and Rathke's cleft cyst, showed uniformly strong reactivity for cytokeratins, epithelial membrane antigen, secretory component, and vimentin, and bound Ulex europaeus lectin. Occasional cells in colloid cysts were positive for Clara cell-specific antigens. Reaction for carcinoembryonic antigen was present on the apical surface of scattered cells of colloid, follicular, and Rathke's cleft cysts. Many cells of follicles in the pars intermedia as well as individual cells of five Rathke's cleft cysts were also immunoreactive for chromogranin, S-100 protein, GFAP, and pituitary hormones. Colloid and enterogenous cysts were negative for prealbumin, S-100 protein, GFAP, and neuron-specific enolase; in all but a few instances, they failed to bind Ricinus communis agglutinin. In contrast, normal choroid plexus and choroid plexus papillomas were positive for prealbumin, S-100 protein, neuron-specific enolase, cytokeratin, vimentin, and Ricinus communis agglutinin receptors; they lacked Ulex europaeus lectin, 56/66-kD cytokeratins, and epithelial membrane antigen. Unlike normal choroid plexus, choroid plexus papillomas were often GFAP-positive. All tissues studied were nonreactive for lysosome, serotonin, and neurofilament, and with Leu-7 antibodies. This study indicates that the immunophenotype of epithelium lining colloid cysts is similar to that of other cysts showing endodermal or ectodermal differentiation and to respiratory tract mucosa. Epithelium of colloid cysts is immunohistochemically different from that of normal or neoplastic choroid plexus. These findings indicate an endodermal rather than neuroepithelial nature for colloid cysts.

Intraparenchymal epithelial (enterogenous) cyst of the medulla oblongata

Intraparenchymal solitary cyst of the medulla oblongata was diagnosed on MRI examination in a 66-year-old woman with a nine year history of progressive brainstem dysfunction and three negative CT scan examinations. Craniotomy and drainage of the cyst to the IVth ventricle led to remarkable clinical recovery. Biopsy of the wall of the cyst revealed an epithelial lining with tonofilaments, desmosomes and surface coating on ultrastructural examination. Immunohistochemistry demonstrated positive reactions of epithelium for keratins, cytokeratins, epithelial membrane antigen and Ulex Europeus lectin, indicating endodermal origin of the cyst.

Intracerebral epithelial cyst: immunohistological diagnosis and endoneurosurgical treatment

This report details an additional case of the very rare instance of a respiratory epithelium-lined intracerebral cyst without communication with the ventricular system. Immunohistologic analysis supports an epithelial rather than neuroectodermal origin. Management using endoneurosurgical techniques is described.

Symptomatic neuroepithelial cysts in the posterior cranial fossa. Immunohistochemical and electron-microscopic studies

A 2-year-old boy had increased intracranial pressure and convulsions because of two extraventricular cysts in the posterior cranial fossa. Releasing the watery cyst contents resulted in disappearance of such clinical manifestations. Immunohistochemically, the epithelial cytoplasm of the cyst was strongly positive for glial fibrillary acidic protein. Electron-microscopically, the cells that lined the cysts had microvilli which were coated with finely granular material to represent "fuzzy" coat, intercellular junctions linking the plasma membranes of adjacent cells, and numerous cytoplasmic glial filaments. The strong positivity for glial fibrillary acidic protein, then, is well correlated with an abundance of the latter. Cilia were also identified. Thus, the cysts were unequivocally neuroepithelial (ependymal) cysts. Only nine cases of neuroepithelial cysts in the posterior cranial fossa, including the current one, have been reported. Three patients were children; six were adults. The age of the patients ranged from 7 months to 60 years. The average age was 21.7 years The sex was known in eight patients with a male to female ratio of 3:5. The pathogenesis of these neuroepithelial cysts was proposed as related to developmental anomalies.

Epithelial cells in symptomatic Rathke's cleft cysts. A light- and electron-microscopic study

Epithelial cells composing symptomatic Rathke's cleft cysts were examined electron microscopically in two cases, and the fine structures were compared with those of the mucosa in the normal sphenoid sinus, of the normal choroid plexuses, and of a craniopharyngioma with goblet and ciliated cells. The Rathke's cleft cysts were composed of a single or pseudostratified epithelial layer abutting on the connective tissue. The epithelial cells were of four different kinds of cells, such as goblet, ciliated, flat, and basal cells. The flat cells containing bundles of tonofilaments and desmosomes were the squamous cells. They were present in a single-epithelial layer in both cases. The basal cells were present as small, wedge-shaped cells, even if the number was very small. The epithelial cells in Rathke's cleft cysts were more similar to those of the mucosa in the sphenoid sinus and those of a craniopharyngioma with goblet and ciliated cells than those of the choroid plexus. This study indicates the close relationship between Rathke's cleft cysts and mucosa in the sphenoid sinus or craniopharyngioma with ciliated and goblet cells.