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ABSTRACT Background In chronic HIV infection, antiretroviral therapy-induced normalization of CD[4.sup.+] T cell counts (immune reconstitution [IR]) is associated with a decreased incidence of opportunistic diseases. However, some individuals remain [...]

Liponeurocytomas are rare and slow-growing tumours located predominantly in the cerebellum. (1) In 2000, the World Health Organization (WHO) Pathology and genetics of tumours of the nervous system (2) described [...]

Precisely speaking, the germ cells are the sex cells, the sperm in the male and the egg in the female. Germ cell tumors actually may involve a variety of different, albeit closely related, cells. Tumors that arise in embryonic tissues are considered germ cell tumors; these include tumors that arise from the membranes associated with the embryo, not just the embryo itself. One example is a yolk sac tumor. Germ cell tumors may be differentiated, as are teratomas, in which the tumor mass has differentiated characteristics resembling more mature tissues. Pure tumors of germ line cells are called germinomas. Germ cell tumors result from the cancerous transformation of a primitive germ cell in the embryo itself. Normally, primitive germ cells do not arise in the region of the testes or ovaries. Rather, they arise elsewhere and migrate through the embryo, only taking up residence in the gonads later on. (The origin of primitive germ cells in man is not known, but in many animals they arise from the membranes outside the embryo.) It is generally thought that when germ cells do not migrate to the right spot, they simply die. However, the cell that has undergone the cancerous transformation may not die, but may persist anywhere in the body, only to form a tumor mass years later in the child or even adult. Sometimes, the tumor develops in the brain. Germ cell tumors are estimated to account for about 1.8 percent of grain tumors in patients under 20 years of age. Germinomas constitute about 16.7 percent of these. Germ cell tumors occur commonly in the region of the pituitary gland, as well as in other areas such as the midline of the cerebellum and the lining of the ventricles. It is not surprising, therefore, that the symptoms of germ cell brain tumors are often those resulting from interference with normal pituitary function. Since the optic nerve passes through this same area, visual defects are common among patients with germ cell brain tumors. Germinomas are especially sensitive to radiation, and relatively low doses may completely destroy a germinoma. However, with proper diagnosis and management, other forms of germ cell tumors, even within the brain, may be successfully eradicated or controlled. (Consumer Summary produced by Reliance Medical Information, Inc.)

The distinctive feature of cancer as opposed to benign tumors is its ability to metastasize, or spread. The dural sheath covering the spinal cord is one of the more common sites for metastases, that is, secondary tumors that have spread from the primary site. These epidural tumors are a prime cause of symptoms, because as they grow the exert force on the spinal cord within the dura; this compression produces a variety of symptoms, which may include incontinence and paralysis. A study was undertaken to evaluate the likelihood of second (or third) epidural metastatic cancer in patients who had already been treated for one epidural metastasis from some systemic cancer. Of 79 patients treated for spinal epidural metastases, second epidural metastases were observed in 13. When the intervals between the first epidural tumor and the second were compared according to the physical distance between the first and second, it was found that the second tumors that developed within a distance of two spinal vertebrae from the first developed an average of 2.8 months later. Conversely, first and second epidural tumors separated by three or more vertebrae were separated in time by an average of 15.2 months. These facts are interpreted as indicating that a second tumor more than three vertebrae away are independent metastases from the primary tumor. On the other hand, epidural tumors that develop two vertebrae or less from the original epidural tumor most likely represent the regrowth of the original epidural tumor, which was not adequately eradicated by treatment. These results suggest that in many cases, the radiotherapy administered for the first epidermal tumor is focused on too small an area, and tumor cells are escaping radiotherapy. Therefore, for patients with epidural metastatic tumors who may be expected to survive for a lengthy time, radiotherapy should be administered to a broader area around the epidural tumor. (Consumer Summary produced by Reliance Medical Information, Inc.)

The recently revised WHO Classification of Tumours of the Central Nervous System (4th edition, 2007) follows in the highly successful footsteps of previous editions of this widely used reference. (1-3) [...]

* Context--The World Health Organization (WHO) recently published its 4th edition of the classification of tumors of the central nervous system, incorporating a substantial number of important changes to the previous version (WHO 2000). The new WHO classification introduces 7 changes in the grading of central nervous system neoplasms, ranging in significance from minor to major, in categories of anaplastic oligoastrocytomas, meningiomas, choroid plexus tumors, pineal parenchymal tumors, ganglioglioma, cerebellar liponeurocytoma, and hemangiopericytomas. The 4th edition also introduces 10 newly codified entities, variants, and patterns, as well as 1 new genetic syndrome. A number of established brain tumors are reorganized, including medulloblastomas and primitive neuroectodermal tumors, in an attempt to more closely align classification with current understanding of central nervous system neoplasia. Objective.--To summarize and discuss the most significant updates in the 4th edition for the practicing surgical pathologist, including (1) changes in grading among established entities; (2) newly codified tumor entities, variants, patterns, and syndromes; and (3) changes in the classification of existing brain tumors. Data Sources.--The primary source for this review is the WHO Classification of Tumours of the Central Nervous System, 4th edition. Other important sources include the 3rd edition of this book and the primary literature that supported changes in the 4th edition. Conclusions.--The new edition of the WHO blue book reflects advancements in the understanding of brain tumors in terms of classification, grading, and new entities. The changes introduced are substantial and will have an impact on the practice of general surgical pathologists and neuropathologists. (Arch Pathol Lab Med. 2008;132:993-1007), The World Health Organization (WHO) classification of central nervous system (CNS) tumors has entered its 4th edition with the recent publication of the WHO Classification of Tumours of the Central [...]

The College of American Pathologists offers these protocols to assist pathologists in providing clinically useful and relevant information when reporting results of surgical specimen examinations. The College regards the reporting [...]

* Context.--As we write, novel antibodies that may well alter the routine practice of surgical neuropathology are in development, characterization, and the early stages of clinical use. These will be used for purposes of tumor subclassification, as prognostic markers, as identifiers of potential therapeutic targets, and as predictors of treatment response. Objective.--To provide for nonspecialists a critical assessment of the peer-reviewed literature (necessarily colored by our own experience) as it pertains to several immunohistochemical reagents that have been recently forwarded as adjuncts to the histologic typing of central nervous system tumors. Data Sources.--We address in these pages only antibodies that are commercially available, that have been the subjects of multiple published series, and that we have had occasion to use in the course of everyday problem solving. Conclusions.--Discussion concentrates on the use of 4 antibodies: BAF47 in the diagnosis of atypical teratoid/ rhabdoid tumor, OCT4 in intracranial germinoma, [beta]-catenin in craniopharyngioma, and NeuN as a marker of neuronal differentiation in neuroepithelial neoplasms., EMBRYONAL NEOPLASMS: BAF47 AND THE IDENTIFICATION OF ATYPICAL TERATOID/RHABDOID TUMORS The atypical teratoid/rhabdoid tumor (AT/RT) shares with rhabdoid tumors of the kidney and soft tissues a predilection for infants and [...]

* Context.--Intraneural perineurioma may be confused with other "onion bulb" Schwann cell entities (localized hypertrophic neuropathy, reactive/demyelinating processes, or inherited polyneuropathies of Charcot-MarieTooth/Dejerine Sottas) due to similar clinical, radiologic, and histologic features. Perineurial and Schwann cells can only be differentiated by ultrastructure and immunohistochemsitry. Objective.--To identify and summarize the clinicopathologic features of true cases of intraneural perineurioma from the English language literature. Data Sources.--A systematic review was performed on definitive intraneural perineuriomas identified through Medline. Baylor College of Medicine-affiliated hospitals' anatomic pathology databases yielded 2 illustrative intraneural perineurioma cases. Study Selection.--Intraneural perineurioma inclusion criteria consisted of characteristic histology and confirmation of perineurial cell lineage by either immunohistochemistry (epithelial membrane antigen positive, S100 protein negative) and/or ultrastructural analysis (thin cytoplasmic processes with an incomplete basal lamina, poorly formed tight junctions, and pinocytotic vesicles). Data Extraction.--Clinicopathologic data were extracted from all identified articles, with subsequent statistical analysis of the following parameters: age, sex, race, tumor location, tumor size, duration of symptoms prior to diagnosis, treatment modalities and outcomes measures, follow-up assessment for tumor recurrence and metastasis, clinical features (history of trauma, motor/sensory abnormalities, clinical/family history), and diagnostic workup (routine histology, immunohistochemistry, ultrastructural analysis, and molecular/cytogenetic characteristics). Conclusions.--Intraneural perineurioma is a neoplastic proliferation of perineurial cells with unique immunohistochemistry and ultrastructural features, and it is distinct from other onion bulb Schwann cell-derived entities. Despite harboring molecular abnormalities of the long arm of chromosome 22, intraneural perineurioma has not been associated with neurofibromatosis. Intraneural perineurioma is a benign peripheral nerve sheath tumor that does not recur or metastasize. (Arch Pathol Lab Med. 2007;131:1382-1392), In the English language literature, intraneural perineurioma is loosely referred to as localized hypertrophic neuropathy/mononeuropathy, hypertrophic neurofibroma, hypertrophic neuropathy, intraneural neurofibroma, interstitial hypertrophic neuropathy, pseudo-onion bulb neuropathy/mononeuropathy and, occasionally, onion [...]