Papillary Tumor of the Pineal Region: A Distinct Molecular Entity.

Papillary tumor of the pineal region (PTPR) is a neuroepithelial brain tumor, which might pose diagnostic difficulties and recurs often. Little is known about underlying molecular alterations. We therefore investigated chromosomal copy number alterations, DNA methylation patterns and mRNA expression profiles in a series of 24 PTPRs. Losses of chromosome 10 were identified in all 13 PTPRs examined. Losses of chromosomes 3 and 22q (54%) as well as gains of chromosomes 8p (62%) and 12 (46%) were also common. DNA methylation profiling using Illumina 450k arrays reliably distinguished PTPR from ependymomas and pineal parenchymal tumors of intermediate differentiation. PTPR could be divided into two subgroups based on methylation pattern, PTPR group 2 showing higher global methylation and a tendency toward shorter progression-free survival (P = 0.06). Genes overexpressed in PTPR as compared with ependymal tumors included SPDEF, known to be expressed in the rodent subcommissural organ. Notable SPDEF protein expression was encountered in 15/19 PTPRs as compared with only 2/36 ependymal tumors, 2/19 choroid plexus tumors and 0/23 samples of other central nervous system (CNS) tumor entities. In conclusion, PTPRs show typical chromosomal alterations as well as distinct DNA methylation and expression profiles, which might serve as useful diagnostic tools.

Pineal germ cell tumors: review.

BACKGROUND: Primary intracranial germ cell tumors represent a rare category of neoplasms, which occur in children and young adults. The WHO classification divides intracranial tumors into germinomas and non-germinomas. The most frequent locality of these tumors is pineal and suprasellar region. Clinical signs and symptoms depend on the localization of the tumour - they most commonly include signs of increased intracranial pressure, Parinauds syndrome, bitemporal hemianopsy and signs of endocrine deficiency. Gadolinium enhanced MRI scan of the brain is the imagining examination of choice in the diagnostic strategy of intracranial germ cell tumors. However, the imagining studies do not provide sufficient information about histological type; therefore, biopsy is necessary. The exception represents cases with characteristically increased levels of tumor markers (AFP and ß-HCG) measured in the serum and cere-brospinal fluid. CASE: A pineal germ cell tumor was observed in a 26-year-old male with presentation of an eye-sight disorder with focusing difficulty and photophobia, accompanied by intensive fatigue and sleepiness, nausea with occasional vomiting, intermittent headaches and Parinauds syndrome. MRI examination of the brain showed tumor expansion in the pineal region and in the right part of the mesencephalon. Radical extirpation of the tumor in the pineal region was performed. The follow-up MRI scan of the brain revealed relapse of the disease. The patient underwent craniospinal radiation therapy with subsequent postoperative chemotherapy (regimen cisplatin and etoposide), three cycles in total. Currently, the patient is 30 months after finishing of oncological treatment in clinical remission of the disease. CONCLUSION: The treatment and prognosis of this neoplasm differ between particular categories. Germinomas have better survival rates than non-germinomas. A 5-year survival rate of germinoma patients after application of radiotherapy alone was > 90% of cases. The addition of chemotherapy lead to a decrease of the dose and minimalization of the irradiated area, with achievement of fewer side effects without a decrease of the curability. Non-germinomas are less radiosensitive than germinomas, but after the application of the adjuvant chemotherapy, survival benefit was achieved. However, the optimal management of these tumors remains controversial.

Pathology of pineal parenchymal tumors.

Tumors of the pineal region can arise from multiple cellular origins and thus represent a very heterogeneous group of pathologies. Such tumors include pineal parenchymal tumors, germ cell tumors, astrocytomas, ependymomas, and papillary pineal tumors. Within the subgroup of pineal parenchymal tumors, there is a histopathologic spectrum ranging from pineocytoma to pineal parenchymal tumors of intermediate differentiation to pineoblastoma. The current World Health Organization classification and the pathologic features of each of the pineal parenchymal tumor subtypes are reviewed in this article.

Pineal tumors.

Pineal tumors are a rare and heterogeneous group of primary central nervous system neoplasms, including pineal parenchymal tumors (pineocytomas, pineal parenchymal tumors of intermediate differentiation, and pineoblastomas), germ cell tumors, and neuroepithelial tumors, such as astrocytomas, ependymomas, and papillary tumor of the pineal region. Their classification has evolved over time, with several updates incorporated into the most recent World Health Organization classification, published in 2007. This review highlights the most recent classification and grading scheme for pineal parenchymal tumors and discusses the newly recognized papillary tumor of the pineal region, including clinicopathologic features, differential diagnosis, and management options.

State-of-the-art pathology: new WHO classification, implications, and new developments.

To keep up with advances in central nervous system (CNS) tumor diagnosis and discovery of new entities, the classification of these tumors requires periodic review and revision. Since the initial 1979 publication from the World Health Organization (WHO) of Histological Typing of Tumours of the Central Nervous System, 3 further editions have been published, cataloging the advances in CNS tumor classification and diagnosis over the past 3 decades. In this article, we discuss select new additions to the current classification, including new diagnostic tools, differential diagnoses, and management implications.

Papillary tumor of the pineal region and spindle cell oncocytoma of the pituitary: new tumor entities in the 2007 WHO Classification.

We have reviewed the features of two recently described intracranial tumors, which have been formally recognized as distinct entities by the 2007 WHO Classification of Brain Tumours: Papillary tumor of the pineal region and spindle cell oncocytoma of the pituitary gland. Their salient clinicopathological features, differential diagnosis, histogenetic hypothesis and outcome are discussed.

Emerging tumor entities and variants of CNS neoplasms.

Since the appearance in 2000 of the World Health Organization (WHO) classification for central nervous system (CNS) neoplasms, numerous descriptions of new entities or variants have appeared in the literature. In the group of neuronal and mixed glioneuronal neoplasms are lesions with distinctive morphological features that are still not included in a precise classification, including extraventricular neurocytoma, papillary glioneuronal tumor, rosette-forming glioneuronal of the fourth ventricle, glioneuronal with neuropil-like rosette, and DNT-like tumor of the septum pellucidum. The glioneuronal tumor with neuropil-like rosette and oligodendroglioma with neurocytic differentiation represent morphological variants of genetically proven diffuse gliomas. The lipoastrocytoma and the pilomixoid astrocytoma enlarge the group of astrocytic lesions. Rare, low-grade gliomas of the spinal cord with extensive leptomeningeal dissemination associated with unusual neuroimaging are described. The chordoid glioma of the third ventricle and the papillary tumor of the pineal region seem to be correlated by a common histogenesis from the specialized ependyma of the subcommissural organ. An embryonal tumor with neuropil and true rosettes combining features of neuroblastoma and ependymoblastoma is discussed. These new, recently described lesions indicate that the complex morphologic spectrum of CNS tumors is far from being completely delineated.

Clinicopathological study on pineocytoma.

Six cases of pineocytoma, which had developed in the parenchyma of the adult pineal body, were examined immunohistochemically and under an electron microscope, after the malignancy of each case had been determined using our classification. One case was rated as grade 1 showing a lobular structure and resembling the normal pineal body. Two cases were rated as grade 2 without a lobular structure but with pineocytomatous rosettes (P-rosettes). Two cases were rated as grade 3 without P-rosettes but with few mitotic figures. One case was rated as grade 4 with marked cellular pleomorphism, numerous mitotic figures and necrotic foci. When examined immunohistochemically, neuron-specific enolase was positive but glial fibrillary acidic protein was negative in all cases. Under an electron microscope, all cases showed abortive synapses, and clear or dense core vesicles. These findings allow us to make two conclusions. First, pineocytoma is always a tumor of neuronal lineage, regardless of their grade of malignancy. Second, the grade 4 pineocytoma should be distinguished from the type of tumor classically called "pineoblastoma." That is, the former seems to be a biologically dedifferentiated tumor, while the latter seems to be biologically undifferentiated tumor.

Systemic staging of supratentorial extra-axial brain tumors in children. Craniopharyngiomas, atypical teratoma and teratoid tumors of the suprasellar region (germinomas), and intracranial teratomas.

A staging system has been proposed for the following tumors: craniopharyngiomas, germinomas, and intracranial teratomas. Various aspects of the specific pathologic and growth characteristics of the tumor determines such categorization and subclassification of the tumors. A brief analysis of the clinical aspects in reference to classification is presented. The suggested systems will need to be tested in clinical studies to determine their validity.

Embryonal central neuroepithelial tumors and their differentiating potential. A cytogenetic view of a complex neuro-oncological problem.

The embryonal central nervous system (CNS) neoplasms are reviewed with special reference to their differentiating potential and in the light of current neuro-oncogenetic concepts partly derived from the experimental induction of neural tumors. The conceptual (and, occasionally, practical) distinction between adult-type and embryonal CNS tumors raises a complex problem, because neoplastic transformation essentially involves replicating stem cells in tissues of renewal and because in the human brain such cells are found mostly in the course of CNS development. A cytogenetic scheme is therefore needed to serve as a frame of reference for a classification of embryonal CNS tumors that will account for the different histological entities documented so far and for the range and the restrictions of their differentiating capabilities. Most embryonal CNS tumors can be fitted into such a scheme. The cerebral medulloepithelioma, the cerebral and cerebellar neuroblastomas, the primitive polar spongioblastoma, and the ependymoblastoma show characteristic morphological features and a correspondingly distinctive cellular differentiating potential. The differentiating capabilities of the cerebellar medulloblastoma, the pineoblastoma, and the retinoblastoma are also distinctive, and are apparently determined by the cytogenesis of the area of the CNS in which the tumors originate. The indiscriminate application of a simplistic concept that would include all the so-called "primitive neuroectodermal tumors" into a single neuroepithelial tumor entity is unlikely to bring further understanding to the problem.

The cytological differentiating potential of pineal parenchymal neoplasms (true pinealomas). A clinicopathological study of 28 tumours.

A series of 28 pineal parenchymal tumours is described, with special reference to the potential of some of these neoplasms to differentiate along glial or ganglionic lines, or both. The more undifferentiated tumours (pineoblastomas, 11 cases) were the most frequent: they are histologically similar to medulloblastomas. One example showed focal differentiation to retinoblastoma at the primary site. The histological features of pineoblastomas merged with those of pineocytomas (7 cases), in which the lobular architecture is reminiscent of that of the mature pineal gland. In addition, 10 further examples in the group of pineocytomas showed more advanced differentiation as follows: towards astrocytes only (2 cases), towards ganglion cells only (1) case) and towards both astrocytes and ganglion cells (gangliogliomas) (7 cases). Confirmation of the pineal parenchymal nature of these neoplasms and of their differentiating potential was provided by a modification of the Achúcarro-Hortega's silver carbonate impregnation technique for pineal parenchymal cells, by specific silver impregnations for axonal processes, and by an immunoperoxidase stain for glial fibrillary acidic (GFA) protein. Electron microscopy of one new example of pineocytoma with neuronal and astrocytic differentiation demonstrated the presence of numerous microtubules, of clear-centred and dense-core vesicles, and of synaptic complexes. Seven illustrative clinical histories with pathological findings are presented. The identification of special features of cellular differentiation is of importance in evaluating the biological behaviour of these neoplasms since a definite correlation can be established between the patient's age, some of the cytological variants, and the malignant potential of the tumour. Pineoblastomas are highly malignant neoplasms of children and young adults which disseminate widely throughout the cerebrospinal fluid pathways. -ineocytomas without cellular evidence of further differentiation occur at any age and are also clinically malignant, but with a somewhat lesser tendency to metastasize than pineoblastomas. Pineobytomas with astrocytic differentiation occur in adults and may be either slowly growing or malignant. Pineocytomas with neuronal or with neuronal and astrocytic differentiation occur in later life, remain localized, and are relatively benign. Since the latter account for approximately one-third of pineal parenchymal tumours and are likely to be relatively radio-resistant, tissue diagnosis is imperative for a determination of the therapeutic approach. Radiation to the entire neuraxis should be administered to patients with pineoblastomas and malignant pineocytomas in view of their high frequency of cerebrospinal metastasis. An accurate histological classification of these tumours therefore carries important clinical and therapeutic implications...