Rhabdoid choroid plexus carcinoma: a rare histological type.

Primary central nervous system atypical teratoid/rhabdoid tumors mostly occur during early childhood and are almost invariably fatal. These tumors show similar histological and radiological features to primitive neuroectodermal tumor, medulloblastoma and choroid plexus carcinoma, but present different biological behaviors. We present the case of an 18 year-old man who presented headache, vomiting and ataxia. CT-scan and MRI revealed a posterior fossa tumor. A gross total resection was performed. An intraoperative study showed papillary-like tumors with large cells and mitotic features. Histological examination showed two different main growth patterns: solid sheets of undifferentiated polygonal cells with papillary features and rhabdoid cells. Immunohistochemically, these rhabdoid cells were positive for vimentin, epithelial membrane antigen, smooth-muscle actin, cytokeratin, S-100 protein, and glial fibrillary acidic protein. Electro-microscopically, the typical rhabdoid cells contained whorled bundles of intermediate filaments in their cytoplasm. A rhabdoid tumor is a clinical-pathological entity and emphasizes the necessity to distinguish this unique tumor from other pediatric central nervous system neoplasms. Cytopathological features, immunohistochemistry and electro-microscopy differential diagnoses are discussed.

Establishment and characterization of a human malignant choroids plexus papilloma cell line (HIBCPP).

A cell line designated "HIBSPP" was established from a human malignant choroids plexus papilloma of 29-year-old Japanese woman. This line grew well without interruption for 3 years and was subcultivated over 70 times. The cells were spindle, oval, and polygonal in shape, and neoplastic and pleomorphic features, a jigsaw puzzle-like arrangement, multilayering and forming papillary structures without contact inhibition. The cells proliferated slowly, and the population doubling time was about 69 hours. The chromosome number showed a wide distribution of aneuploidy. The mode was in the hypotetraploid range, and many marker chromosomes were observed. The culture cells were easily transplanted into the subcutis of nude mice and produced the tumor resembling the original tumor.

Case of the month. May 1996--hydrocephalus in a 9 month old infant.

A 9 month old infant presented with hydrocephalus. MRI studies revealed a large cystic space with a nodule that was bright on T-1 weighted images and dark on T-2 weighted images. It was bright with contrast enhancement. The surgical specimen was noted to be dark black. Microscopic examination revealed a benign papillary tumor consistent with a choroid plexus papilloma which was heavily pigmented with melanin. Immunohisto-chemical stains were consistent with a choroid plexus papilloma, but they also showed many epithelial cells to be positive for HMB-45. Ultrastructural studies demonstrated melanosomes and pre-melanosomes in cells with well-delineated basal lamina. This is the first case to demonstrate melanosomes in a benign choroid plexus papilloma. Previously reported cases of pigmented lesions of the choroid plexus either contained neuromelanin in the benign examples or melanosomes in two cases of choroid plexus carcinomas.

Chordoid glioma of the third ventricle: an ultrastructural study of three cases with a histogenetic hypothesis.

Chordoid glioma is a rare neoplasm occurring in the third ventricle and, as the name implies, having a chordoid appearance. It is currently considered a glial neoplasm of uncertain histogenesis with distinct clinicopathologic features. We report three cases of chordoid glioma with a focus on the ultrastructural appearance. The patients were two men and one woman aged, respectively, 34, 40, and 43 years. Immunohistochemically, all tumors showed strong and diffuse reactivity for glial fibrillary acidic protein and vimentin, whereas immunoreactivity for epithelial membrane antigen and cytokeratin was focal. Ultrastructurally, they showed features of ependymal differentiation for the presence of an apical pole with microvilli and a basal pole characterized, as in normal ependyma, by many hemidesmosomelike structures connecting cell membranes to the underlying basal lamina. Constant features were a submicroscopic cell body zonation (i.e., perinuclear, intermediate, subapical, and apical regions) and the presence of secretory granules. These findings were similar to those described for the secretory ependymal cells of the subcommissural organ, a small structure located in a dorsocaudal region of the third ventricle that undergoes regression after birth in humans. Our observations suggest that chordoid glioma may represent a subtype of ependymoma whose cells resemble the highly specialized ependyma of the subcommissural organ.

The AgNOR technique, PCNA immunohistochemistry, and DNA ploidy in the evaluation of choroid plexus biopsy specimens.

The histologic distinctions between normal choroid plexus and choroid plexus papilloma and between choroid plexus papilloma and choroid plexus carcinoma are sometimes difficult. The authors performed the silver nucleolar organizer region (AgNOR) technique, immunohistochemistry for proliferating cell nuclear antigen (PCNA), and DNA ploidy analysis by flow cytometry on 9 samples of normal choroid plexus, 8 papillomas, and 13 carcinomas to evaluate whether these techniques can aid in these differential diagnoses. Significant differences were found in the mean AgNOR count between normal choroid plexus (1.35 +/- 0.11) and choroid plexus papillomas (2.42 +/- 0.81) (P < 0.001), but not between choroid plexus papillomas and carcinomas. In the normal choroid plexus, AgNORs were smooth and round; in the papillomas and carcinomas, however, they varied in size and shape. Compound AgNORs were commonly present in the tumors but were essentially absent in controls. Antibody to PCNA did not stain normal choroid plexus cells (except for focal staining in one sample of normal choroid plexus adjacent to a carcinoma) but stained many papilloma and carcinoma cells. DNA ploidy analysis demonstrated aneuploidy in some papillomas and carcinomas but could not be used for the distinction of normal choroid plexus from papillomas. These results suggested that the AgNOR technique and PCNA immunohistochemistry could be used to distinguish normal choroid plexus from choroid plexus papilloma in small, diagnostically difficult biopsy specimens.

Pigmented choroid plexus carcinoma: a cytogenetic and ultrastructural study.

A pigmented choroid plexus carcinoma was studied. The pigment was Fontana-positive, and the neoplastic cells focally expressed melanosomal marker HMB45 and contained probable aberrant melanosomes. The tumor was composed of two pseudodiploid clones, having the karyotypes 46,XY,inv(4)(q12q35),t(6;15)(q21;q22),inv(7)(p11.2q22),t(19; 22) (q13.4;q11.2)[15]/46,XY,t(4;14)(q31.1; p11.2),t(12;13)(p11.1;q34)[6]. The available data seem to indicate that rearrangements of 7p11-12, 9q11-12, 15q22, and 19q13.4 may play a role in the development of choroid plexus carcinomas.

[Carcinomatosis of the choroid plexus: clinical case and necropsy findings]. / Carcinomatosis de plexos coroideos: caso clínco y hallazgos necrópsicos.

INTRODUCTION: Carcinomas of the choroid plexus are a rare malignant variety of papillary tumours which originate in the choroid plexus. Their occurrence in adults has been questioned because of the difficulty in differentiating them from the metastases of adenocarcinomas. CLINICAL CASE AND CONCLUSIONS: We present the case of a 57 year old man with a rapidly progressive illness characterized by disorientation, behaviour changes and amnesia, progressive deterioration of the level of consciousness until he was in deep coma and died (all within one month). There was no clinical evidence of the presence of a primary extra-cranial tumour. On magnetic resonance there was obliteration of the ventricular system with a protein material and thickening and increased marking of the ependyma walls, compatible with ventriculitis. Necropsy, limited to the skull, showed the presence of a malignant infiltrating tumour with papillary morphology, which affected the choroid plexuses of the whole ventricular system, infiltrated the adjacent nervous tissue and extended to the leptomeninges. These findings suggest a differential diagnosis between carcinoma of the choroid plexus and metastatic meningeal carcinoma.

Third ventricular chordoid glioma: clinicopathological study of two cases with evidence for a poor clinical outcome despite low grade histological features.

Chordoid glioma of the third ventricle is a rare glial tumour whose precise histogenesis remains uncertain. We describe two cases that presented recently to our department and review the background literature. The neoplasm tends to occur in women and its clinical presentation is variable, resulting from acute hydrocephalus or impingement upon local structures. However, the radiological appearance is distinct, with an ovoid shape, hyperdensity and uniform contrast enhancement on computerized tomography and magnetic resonance imaging. Intraoperative smear diagnosis is difficult because of the lack of specific features, although the presence of metachromatic extracellular mucin may be useful. The characteristic histological appearance is that of cords and clusters of cohesive, oval-to-polygonal epithelioid cells with abundant eosinophilic cytoplasm and a mucinous background. There is often a mixed chronic inflammatory infiltrate with lymphocytes and plasma cells with Russell bodies. The main differentials for histological diagnosis include chordoid meningiomas, pilocytic astrocytomas and ependymomas. An immunohistochemical panel including antibodies to glial fibrillary acidic protein, CD 34, epithelial membrane antigen, pan cytokeratin, S100 and vimentin can be used to distinguish between these possibilities. Ultrastructurally the tumour cells have basal lamina and microvilli, reminiscent of ependymomas. The clinical outcome in our cases was poor because of the location of the lesion and its close relation to the hypothalamus. Limited follow-up after surgery with or without radiotherapy suggests that as-full-as-possible resection favours a better outcome, although surgery in this area carries significant operative risks.

Melanotic papilloma of the choroid plexus: report of a case with implications for pathogenesis.

A case of pigmented choroid plexus papilloma removed from the 4th ventricle of a 43-year-old man is reported. The tumor showed histologic, immunophenotypic, and ultrastructural features of neoplastic choroid plexus epithelium. There was no evidence of melanosomal activity or neurosecretion. The pigment consisted of an intimate association of lipofuscin and neuromelanin, indicating autocatalytic peroxydation of the former as a putative way of melaninogenesis. The low proliferation rate of the tumor together with immunohistochemical evidence of inactivation of p53 protein suggest a delayed turnover of neoplastic cells as a possible source of lipofuscin accumulation.

Immunohistochemical and ultrastructural study of chordoid glioma of the third ventricle: its tanycytic differentiation.

A chordoid glioma in the third ventricle was studied immunohistochemically and ultrastructurally. In this report, special attention is paid to the histogenesis in relation to the pathological appearance and unique anatomic location of this tumor. Light microscopic and immunohistochemical findings were similar to those reported previously. Ultrastructurally, microvilli were frequently seen, but three types of abnormal cilia were rarely observed. Basement membrane around the tumor cells and microvessels was extensive. Poorly to moderately developed intermediate (adherent) junctions were frequently seen. Resemblance of these ultrastructural features of the tumor to embryonic tanycytes suggests the tanycytic differentiation of chordoid glioma. Neuroradiologically, all of the previously reported cases of chordoid gliomas seem to arise in the anterior part of the third ventricular floor. This region includes the lamina terminalis, infundibular recess and median eminence, which corresponds to a tanycyte-rich area. These findings suggest a tanycytic origin of chordoid glioma.

Suprasellar chordoid glioma combined with Rathke's cleft cyst.

Chordoid glioma has been recently described as a slow-growing neoplasm with chordoid appearance, occurring exclusively in the regions of the third ventricle and hypothalamus of middle-aged women. We experienced a case of a 48-year-old woman with a suprasellar tumor composed of chordoid glioma and Rathke's cleft cyst, which was confirmed by histopathological, immunohistochemical and electron microscopic examinations. Histologically, chordoid glioma comprised the major part of the tumor, and the prominent Rathke's cleft cysts were distributed focally in the same tumor tissue without any transitions. Chordoid glioma was immunoreactive for glial fibrillary acidic protein, S-100 protein and vimentin, and focally positive for epithelial membrane antigen and CD34, while cytokeratin highlighted epithelial cells lining Rathke's cleft cysts. Ultrastructural examination of the chordoid glioma revealed short cytoplasmic processes, intermediate filaments, intercellular junctions of zonular adherens type, basal lamina, secretory granules and pinocytic vesicles. The ultrastructural observations of the current case are similar to those of the subcommisural organ, although cell body zonation or microvilli were not evident. The coexistence of chordoid glioma and Rathke's cleft cyst has not been reported previously and may represent a collision tumor.

Targeting T cells against brain tumors with a bispecific ligand-antibody conjugate.

High-affinity receptors expressed on the surface of some tumors can be exploited by chemically conjugating the ligand for the receptor and an antibody against immune effector cells, thus redirecting their cytolytic potential against the tumor. Ovarian carcinomas and some brain tumors express the high-affinity folate receptor (FR). In this report, a transgenic mouse model that generates endogenously arising choroid plexus tumors was used to show that folate/anti-T-cell receptor antibody conjugates can direct infiltration of T cells into solid brain tumor masses. An engineered single-chain Fv form of the anti-T-cell receptor antibody KJ16 was conjugated with folate, to produce a bispecific agent that was substantially smaller than most previously characterized bispecific antibodies. Folate conjugation to the antibody increased T-cell infiltration into the tumors by 10- to 20-fold, and significantly prolonged survival of the mice.

Rhabdoid choroid plexus carcinoma: a rare histological type

Primary central nervous system atypical teratoid/rhabdoid tumors mostly occur during early childhood and are almost invariably fatal. These tumors show similar histological and radiological features to primitive neuroectodermal tumor, meduloblastoma and choroid plexus carcinoma, but present different biological behaviors. We present the case of an 18 year-old man who presented headache, vomiting and ataxia. CT-scan and MRI revealed a posterior fossa tumor. A gross total resection was performed. An intraoperative study showed papillary-like tumors with large cells and mitotic features. Histological examination showed two different main growth patterns: solid sheets of undifferentiated polygonal cells with papillary features and rhabdoid cells. Immunohistochemically, these rhabdoid cells were positive for vimentin, epithelial membrane antigen, smooth-muscle actin, cytokeratin, S-100 protein, and glial fibrillary acidic protein. Electro-microscopically, the typical rhabdoid cells contained whorled bundles of intermediate filaments in their cytoplasm. A rhabdoid tumor is a clinicalpathological entity and emphasizes the necessity to distinguish this unique tumor from other pediatric central nervous system neoplasms. Cytopathological features, immunohistochemistry and electro-microscopy differential diagnoses are discussed.

Los tumores de tipo rabdoide primarios en cualquier sitio son raros y en el sistema nervioso central son extremadamente raros y ocurren principalmente en niños, el tumor teratoide/rabdoide es el tumor más frecuente dentro de este grupo y de evolución clínica fatal. El tumor neuroectodermico primitivo, medulobalstoma y al carcinoma de plexos coroides son tumores generalmente muestran aspectos clínicos radiológicos e histológicos similares, con evolución diferente. Presentamos el caso de un hombre joven de 18 años que inició con cefalea vómitos y ataxia. La imagen de TC muestra tumor en fosa posterior. Se realizó resección total del tumor. En el estudio transoperatorio se observó neoplasia maligna de células grandes con mitosis y que formaba estructuras papilares. Histológicamente se observaron dos patrones diferentes, uno formado por nidos sólidos de células poligonales indiferenciadas con formación de estructuras papilares y el otro con abundantes células grandes de aspecto rabdoide. Por inmunohistoquímica las células de aspecto rabdoide fueron positivas para vimentina, antigeno de membrana epitelial, actina de músculo liso, citoqueratina, y proteína S-100, La PGAF fue focalmente positiva. Se realizó microscopía electrónica de las células rabdoides que mostraban nidos irregulares de filamentos intermedios intracitoplasmicos y lamina basal. El tumor rabdoide cerebral es clínica como histológicamente una rara entidad en la población pediátrica. Se discute el aspecto citopatológicas de inmunohistoquímica y de microscopia electrónica y sus diagnósticos diferenciales.