Cytology of Extraneural Metastases of Nonhematolymphoid Primary Central Nervous System Tumors: Six Cases with Histopathological Correlation and Literature Update.

INTRODUCTION: Extraneural/-cranial metastases (ENM) of primary central nervous system (CNS) tumors are rare and may be diagnostically challenging. We describe the cytomorphological and pertinent clinical features of ENM in a case series assessed by fine-needle aspiration (FNA). A search of the laboratory information systems of 2 tertiary care centers in Toronto (2000-2015) was performed. Cases with direct extracranial/-spinal extension of CNS neoplasms were excluded. Microscopic slides of FNA and surgical specimens were reviewed. Demographic and clinicopathological data were retrieved. CASE PRESENTATION: Six cases were identified with the original diagnoses of glioblastoma, glioblastoma with primitive neuroectodermal tumor-like components, anaplastic ependymoma, myxopapillary ependymoma, atypical meningioma, and hemangiopericytoma. Median patient age at first diagnosis was 44 years (range 22-56). The time interval between initial diagnosis and first metastatic disease manifestation was 3 months to 19 years. All FNA diagnoses were rendered correctly. In 4 cases, immunohistochemistry was used to support the diagnosis. All cases had prior surgical intervention at the primary tumor site. In 4 cases, the ENM location was the ipsilateral parotid or buccal area. Two primary tumors in midline location developed ENM in the scapular area. DISCUSSION/CONCLUSION: ENM are a rare manifestation of a range of different primary CNS tumors and may involve the ipsilateral head and neck mimicking clinically a salivary gland neoplasm. FNA can rapidly discriminate ENM from other, potentially more indolent conditions. Awareness of the clinical history is paramount to avoid diagnostic confusion.

Neural and neurogenic tumours of the gastroenteropancreaticobiliary tract.

Neural lesions occur uncommonly in the gastroenteropancreaticobiliary tract. However, due to the growing number of screening colonoscopy procedures, polypoid neural lesions of the colon are being recognised increasingly and range from benign tumours to high-grade malignant neoplasms. Morphological variability of neural tumours can be wide, although some entities share pathological features, and, as such, these lesions can be diagnostically challenging. We review the spectrum of pathology of neural tumours in the gastroenteropancreaticobiliary tract, with the goal of providing a practical approach for practising surgical pathologists.

Multinodular and vacuolating neuronal tumor of the cerebrum. A rare entity. New case and review of the literature.

BACKGROUND: Multinodular and vacuolating neuronal tumor has been recently described and included in the World Health Organization Classification of Tumors of The Central Nervous System, even though its consideration as a true tumor is controversial. Patients with these lesions usually present with refractory seizures and inconclusive imaging findings that may be confused with other more common diagnoses such as dysembryoplastic neuroepithelial tumors or low-grade gliomas. Therefore, surgical resection is warranted to reach a pathologic diagnosis and seizure control. To the best of our knowledge, only 16 cases have been published in the English literature. CASE DESCRIPTION: We present the case of a 52-year-old male who presented at our institution with a 2-year-history of absence of seizures. Brain MRI showed a T2-hyperintense lesion with no contrast enhancement affecting his temporal lobe. Temporal craniotomy and microsurgical resection was scheduled. The procedure was uneventful and a grayish, gluey mass was sent for pathologic analysis. The tumor was formed by immature neuronal cells organized in nodules with a vacuolated matrix. A thorough immunohistochemical analysis showed positivity for: Protein Gene Product 9.5. ATRX. OLIG2. SOX10. p16. Nestin. Synaptophysin. The findings were consistent with multinodular and vacuolating neuronal tumor. The patient has been seizure-free after surgery and with no signs of tumor progression. CONCLUSION: We present a thorough review addressing this uncommon tumor along with a description of the 17th reported case of MVNT, a tumor that was described for the first time in 2013. Further studies and case studies are necessary to establish a well-defined morphological and immunohistochemical profile along with knowledge about its natural history.

Braided pattern in a dermatofibrosarcoma protuberans: a potential mimicker of neural neoplasms.

Dermatofibrosarcoma protuberans (DFSP) is a dermal and subcutaneous slow-growing tumor of intermediate malignancy. Different histological variants of DFSP have been described, depending on cellular and stromal peculiarities. Here, we report the histological features of a DFSP in which cells were frequently arrayed in cords and fascicles that were interweaved, conforming a peculiar braided pattern. This finding might pose difficulties in the differential diagnosis with neural neoplasms and expands the morphological spectrum of DFSP.

Ectopic neural and neuroendocrine neoplasms.

Although neural and neuroendocrine tissues are distributed virtually ubiquitously throughout the body, the occurrence of selected neoplasms related to those lineages is extremely uncommon in some topographic sites. This review considers the clinicopathologic characteristics of heterotopic pituitary adenomas; neuroendocrine carcinomas in non-organ-based locations; ectopic (extraneuraxial) meningiomas and gliomas; visceral neuroblastic neoplasms and primitive neuroectodermal tumors; and paragangliomas arising outside the sympathoadrenal neural network. Practical approaches to differential diagnosis are emphasized.

Gastrointestinal stromal tumours: evaluation of biological and clinical current opinions.

The discovery of c-kit gene mutations and the positivity of its transcription products in gastrointestinal stromal tumours (GISTs) suggest a possible origin from Cajal interstitial cells. The study population consisted of 12 patients with GIST, with a mean age of 67.6 years. Preoperative biopsy was performed in 4 cases and in only 1 case did it prove correct. Mesenchymal tumours were regarded as myogenic when they were positive for desmin, and as neurogenic when they were positive for S-100 protein or specific neural enolase (SNE). Seven out of 12 patients underwent simple tumour excision, while in 2 cases ileal resection was performed; gastric resection, total gastrectomy with D2 lymphadenectomy and left colectomy were carried out in one case each. There were two deaths, both unrelated to the primitive diagnosis. Immunohistochemical studies were positive for CD34 in 58% of the cases, and for CD117 in 83%. The mitotic count was higher than 5/10 HPF in 3 cases. The mean survival was 57 months. The overall survival rate was 66%. We found that good tumour differentiation, small size and a low mitotic index correlate with benign behaviour and a better prognosis. Positivity for CD117, evaluated in all malignant lesions, was slightly lower (83% vs 89%) as compared to the data reported in the literature. Tumours with a high mitotic index (> 5 mitoses/10 HPF) and measuring more than 5 cm in diameter are to be considered malignant.

The survivin:Fas ratio is predictive of recurrent disease in neuroblastoma.

BACKGROUND/PURPOSE: Several clinical and biologic features of neuroblastoma (NB) are used to predict the risk of recurrent disease. The balance between antiapoptotic and proapoptotic factors within a tumor may affect its ability to survive. Survivin is an antiapoptotic factor expressed in highly proliferative NB, whereas Fas is a proapoptotic factor that portends a favorable prognosis. The authors determined whether the ratio of survivin to Fas (S:F ratio) is predictive of recurrent disease in patients with NB. The authors previously have shown the S:F ratio is predictive of recurrent disease in pediatric renal tumors. METHODS: The authors quantified the levels of 9 different apoptotic mRNA species using Rnase Protection assay (RPA, Riboquant, PharMingen, San Diego, CA). Twenty-eight primary tumor specimens were evaluated from patients with ganglioneuroma (n = 3), ganglioneuroblastoma (n = 2), and neuroblastoma (n = 23) from tumors of all clinical stages obtained at the time of diagnosis. mRNA levels were calculated as a percentage of L32 for each specimen assayed, and positive expression was assumed to be greater than 10% of L32. RESULTS: Survivin was expressed in 90% of tumors that went on to recur and only in 27.7% of those that were cured. The S:F ratio was significantly greater in tumors that went on to recur (n = 10) compared with those from patients that were cured (n = 18) (median S:F ratio, 3.3 v 0.75; P =.0002, Wilcoxon rank-sum test). A cutoff ratio of 2.3 was highly predictive of tumor recurrence irrespective of clinical stage of disease (area under ROC curve = 0.906). Sensitivity was 80% (CI, 44.4% to 97.5%), specificity was 94.4% (CI, 72.7% to 99.9%), positive predictive value was 88.9% (CI, 51.8% to 99.7%), and negative predictive value was 89.5% (66.9% to 98.7%). Twenty-five of 28 (89.3%) tumor ratios were correct in predicting outcome. CONCLUSIONS: The survivin:Fas ratio in primary tumors may be used to predict the risk for recurrent disease in patients with NB. The S:F ratio appears to be a more sensitive predictor of recurrent disease than survivin expression alone. Determining this ratio may not only be helpful in guiding follow-up of patients with NB, but also may aid in stratifying patients for more aggressive therapeutic strategies.

[Mixed neuroglial tumor: description of a case]. / Tumore misto neurogliale: descrizione di un caso.

A case of neuroglial tumor in a 18-year-old man is presented. The neoplasm was composed by two cell types. One type showed features typical of neuronal cells, while the other resembled glial cells. The diagnosis was confirmed by immunohistochemistry results.

[Cutaneous neural neoplasms--an update]. / Kutane Tumoren des Nervenhüllgewebes. Eine Ubersicht.

Until recently, benign cutaneous neural tumours which do not fulfil criteria for either neurofibrom or schwannoma often were lumped into the broad category of benign peripheral nerve sheath tumours (PNST). However, during the last years a number of new entities of neural tumours have been described, and advances in immunohistochemistry and electronmicroscopy have helped us to better understand the cytological differentiation in these neoplasms. The knowledge of these distinctive neoplasms is necessary in order to avoid diagnostic pitfalls and misdiagnosis of more aggressive neoplasms. These distinctive lesions include: neurothekeoma, which can divided into classical myxoid and cellular types showing characteristic histological and immunohistochemical features. Typical neurothekeoma (nerve sheath myxoma) is a lobular or nodular dermal neoplasm composed of plump spindled or stellated, S-100 positive tumour cells set in a maxoid stroma. In contrast, cellular neurothekeoma is characterized as an ill-defined dermal neoplasm composed of concentric nests and fascicles of spindle-shaped and epithelioid tumour cells, which are S-100 negative but stain positively for NKIC3. The evidence of intermediate forms of neurothekeoma showing features of ordinary hypocellular neurothekeoma and cellular neurothekeoma, as well as ultrastructural studies, emphasize that both variants represent a spectrum of neurothekeoma; solitary circumscribed neuroma ("palisaded encapsulated neuroma") manifests mainly as a skin-colored or pink papule or nodule, and is most often located on the face. Histologically, solitary circumscribed neuroma is a well-circumscribed round or ovoid dermal neoplasm composed of interwoven fascicles of schwann cells, which stain positively for S-100 protein and numerous neurofilament positive axons surrounded partly by fibroblasts and EMA-positive perineural cells; perineurioma is a rare well-circumscribed neoplasm which occurs mainly in subcutaneous tissue and only rarely in the dermis and in deep soft tissues. Perineurioma is composed of elongated bipolar spindle-shaped tumour cells which are arranged in storiform, whorled, linear or lamellated growth patterns, The tumour cells stain positively for vimentin and EMA, and for CD 34 in a number of cases, but lack positivity for S-100 protein, neurofilament and desmoplakin. In addition unusual forms of schwannoma (cellular schwannoma, solitary plexiform schwannoma, melanotic schwannoma) and neurofibroma ("atypical" (bizarre) neurofibroma, diffuse neurofibroma, epithelioid neurofibroma) are briefly discussed.

Gastrointestinal autonomic nerve tumor (plexosarcoma): report of a case with fine needle aspiration biopsy and histologic, immunocytochemical and ultrastructural study.

BACKGROUND: Gastrointestinal stromal tumors (GISTs) encompass a large group of mesenchymal neoplasms that display common cytologic spindle-shaped morphology on light microscopy. Immunocytochemical and ultrastructural studies can demonstrate several patterns of differentiation. CASE: A 70-year-old male presented with two intraabdominal small bowel masses. The cytopathologic features of a fine needle aspiration biopsy (FNAB) included plump spindle cells in densely populated aggregates or in a fasciculated pattern, without significant pleomorphism. An epithelioid component in a lobular arrangement with abundant, eosinophilic cytoplasm was also noted. The nuclei were vesicular, with a very evident, eosinophilic nucleolus and finely distributed chromatin. Groups of loosely cohesive cells with slender, dendritic-like cytoplasm were evident. Immunocytochemical study of the embedded, fine needle aspirated fragments of the neoplasm demonstrated immunoreactivity for vimentin and neuron-specific enolase. Cytokeratin immunoreactivity or muscular, vascular, neuroendocrine or nerve sheath differentiation failed to be demonstrated. The cytologic and immunocytochemical findings correlated well with the histologic features of the neoplasm. The morphologic diagnosis was confirmed by ultrastructural study. CONCLUSION: FNAB and immunocytochemistry can be valuable in making the correct diagnosis between gastrointestinal stromal tumors.

gp130RB13-6-positive neural progenitor cells are susceptible to the oncogenic effect of ethylnitrosourea in pre-natal rat brain.

Proliferation-competent rat brain precursor cells of glial lineages are thought to preferentially undergo malignant transformation after transplacental exposure to ethylnitrosourea (EtNU). We recently have reported that monoclonal antibody (mAb) RB13-6 recognizes a developmentally regulated 130 kDa cell surface glycoprotein (gp130RB13-6) transiently expressed by a small subpopulation of glial progenitor cells in pre-natal rat brain. The expression of gp130RB13-6 has now been analysed immunocytochemically in malignant gliomas induced on day 15, 18 or 21 of gestation and in long-term cultures of fetal brain cells (FBC) isolated after in vivo-exposure to EtNU on day 18 of gestation. Malignant gliomas induced at different gestational stages contained varying proportions of gp130RB13-6-positive cells, whereas a subpopulation of proliferative neural progenitor cells exhibiting sustained gp130RB13-6 expression persisted in long-term FBC cultures after 3 months. This subpopulation, which was not selected for in control cultures of FBC derived from buffer-treated rats, gave rise to malignant cell lines after a period of time similar to the latency period required for glioma development in vivo. These data suggest that gp130RB13-6-positive cells of the immature rat nervous system may represent a subset of neural progenitor cells particularly susceptible to the oncogenic effect of EtNU.

Role of cell cycle regulators in tumor formation in transgenic mice expressing the human neurotropic virus, JCV, early protein.

Transgenic mice harboring the early genome from the human neurotropic JC virus, JCV, develop massive abdominal tumors of neural crest origin during 6-8 months after birth and succumb to death a few weeks later. The viral early protein, T-antigen, which possesses the ability to transform cells of neural origin, is highly expressed in the tumor cells. Immunoblot analysis of protein extract from tumor tissue shows high level expression of the tumor suppressor protein, p53, in complex with T-antigen. Expression of p21, a downstream target for p53, which controls cell cycle progression by regulating the activity of cyclins and their associated kinases during the G1 phase, is extremely low in the tumor cells. Whereas the level of expression and activity of cyclin D1 and its associated kinase, cdk6, was modest in tumor cells, both cyclin A and E, and their kinase partners, cdk2 and cdk4, were highly expressed and exhibited significant kinase activity. The retinoblastoma gene product, pRb, which upon phosphorylation by cyclins:cdk induces rapid cell proliferation, was found in the phosphorylated state in tumor cell extracts, and was detected in association with JCV T-antigen. The transcription factor, E2F-1, which dissociates from the pRb-E2F-1 complex and stimulates S phase-specific genes upon phosphorylation of pRb and/or complexation of pRb with the viral transforming protein, was highly expressed in tumor cells. Accordingly, high level expression of the E2F-1-responsive gene, proliferating cell nuclear antigen (PCNA), was detected in the tumor cells. These observations suggest a potential regulating pathway that, upon expression of JCV T-antigen, induces formation and progression of tumors of neural origin in a whole animal system.

Comparative immunoreactivity of CD-68 and HMB-45 in malignant melanoma, neural tumors and nevi.

The monoclonal antibody CD 68 (KP 1) reacts with fibrohistiocytic and some epithelial neoplasms; its reactivity compared with that of HMB 45 in malignant melanoma (MM) and neural tumors needs further elucidation. Using a streptavidin-biotin-immunoperoxidase procedure, we examined the reactivity of 65 MM (46 conventional, 1 polypoid, 6 desmoplastic [DMM], and 12 metastatic), 21 neurofibromas, 1 neurofibrosarcoma, 10 schwannomas, 1 perineurioma, 2 neurothekeomas, and 14 blue and 26 other nevi for CD-68, HMB-45-defined antigen, S 100 and neurofilament protein. A positive staining for CD 68 was observed in 38 of 42 primary, 5 of 6 DMM, and 11 of 12 metastatic melanomas; 6 of 10 schwannomas; 5 of 10 nevi with junctional component and all 14 blue nevi. All 21 neurofibromas, 1 each neurofibrosarcoma and perineurioma, both neurothekeomas, and all 12 nevi with dermal component were CD 68-negative. HBM 45 was expressed by all 44 primary, none of 6 DMM, and 7 of 12 metastatic melanomas; by none of 10 schwannomas, 6 neurofibromas, 1 neurofibrosarcoma, 1 perineurioma and 2 neurothekeomas. Both junctional nevi, 8 of 10 nevi with junctional components, 1 of 10 dermal components of junctional nevi, and 11 of 13 blue nevi were also HMB 45 positive. Except for 1 perineurioma, S 100 decorated all tumors examined. NF was immunoreactive in 1 of 45 conventional melanomas, 2 of 21 neurofibromas, 2 of 10 schwannomas, and 3 of 10 blue nevi; it was non-reactive in all polypoid, desmoplastic and metastatic melanomas; neurofibrosarcoma, perineurioma, neurothekeoma and other nevi. We conclude that the CD-68-reactivity in primary melanomas, neurofibromas, neurofibrosarcomas, perineuriomas, and nevi was similar to that of HMB 45. The significantly higher CD 68-positivity than of HMB 45 in metastatic and desmoplastic melanomas and schwannomas may be of diagnostic value.

Angiosarcoma arising in a solitary schwannoma (neurilemoma) of the sciatic nerve.

Angiosarcomas rarely develop within a peripheral nerve or a peripheral nerve sheath tumor. We describe an epithelioid angiosarcoma that arose in a benign schwannoma (neurilemoma) of the right thigh in a 65-year-old man who did not have von Recklinghausen's disease. Histologically, the resected tumor was a high-grade undifferentiated sarcoma that was predominantly arranged in solid sheets or nests and composed of epithelioid cells. The endothelial origin of the tumor was suggested by Factor VIII R-ag, Ulex europaeus-I, CD34, CD31, BNH9, and vimentin immunoreactivity, along with the ultrastructural evidence of occasional Weibel-Palade bodies. In this location, epithelioid angiosarcoma should be distinguished from malignant transformation of a schwannoma with epithelioid changes. This observation stresses the importance of immunohistochemical and ultrastructural analysis in the differential diagnosis of vascular tumors with features of epithelioid sarcoma.

NeuN: a useful neuronal marker for diagnostic histopathology.

The monoclonal antibody A60 specifically recognizes the DNA-binding, neuron-specific protein NeuN, which is present in most neuronal cell types of vertebrates. In this study we demonstrate the potential use of NeuN as a diagnostic neuronal marker using a wide range of formalin-fixed, paraffin-embedded human surgical and autopsy specimens from the central and peripheral nervous system. After microwave antigen retrieval, almost all neuronal populations revealed strong immunoreactivity for NeuN in nuclei, perikarya, and some proximal neuronal processes, whereas more distal axon cylinders and dendritic ramifications were not stained. The stain greatly enhanced the gray matter architecture. NeuN immunoreactivity was not detected in Purkinje cells, most neurons of the internal nuclear layer of the retina, and in sympathetic chain ganglia. We examined nine gangliogliomas and 14 dysembryoplastic neuroepithelial tumors, one ganglioneuroma, and one dysplastic cerebellar gangliocytoma. The neuronal component of all of these lesions showed marked immunoreactivity for NeuN. In addition, NeuN immunoreactivity was focally seen in one of seven medulloblastomas with prominent neuronal differentiation. There was no staining of non-neuronal structures. The results indicate that NeuN immunoreactivity is a sensitive and specific neuronal marker in formalin-fixed, paraffin-embedded tissues, and may be useful in diagnostic histopathology.

Florid vascular proliferation associated with neural and neuroendocrine neoplasms. A diagnostic clue and potential pitfall.

We report the light microscopic and immunohistochemical features of vascular proliferations associated with 26 extracranial neural and neuroendocrine neoplasms including esthesioneuroblastoma, neuroblastoma/ganglioneuroblastoma, the primitive neural component of immature teratoma, mediastinal teratoma, primitive neuroectodermal tumor, intra-abdominal desmoplastic small cell tumor, Merkel cell carcinoma of the skin, and thyroid medullary carcinoma. These vascular proliferations were similar to those associated with high-grade glial neoplasms and were characterized by tufts of vessels with a glomeruloid configuration or by long cords of vessels. Immunohistochemical evaluation documented the presence of endothelial cells, perithelial cells, and basement membrane components within the foci of proliferating vessels. We propose that these vascular proliferations represent a characteristic feature of the neuroendocrine/neural neoplastic phenotype and that they possibly arise as the result of angiogenic factors produced by the neoplastic cells. The presence of these distinctive vascular lesions in the stroma of a poorly differentiated neoplasm should alert the pathologist to the possibility of the neoplasm being of a neural or neuroendocrine nature.

Gastro-intestinal stromal tumors: an ultrastructural reinterpretation of the clear cell component.

The histology, immunohistochemistry and ultrastructure of six gastro-intestinal stromal tumors of the stomach (GSTs) showing a focal to diffuse clear cell component are reported. At light microscopy, all GSTs had typical histopathological features with one case additionally displaying stromal myxoid changes and scattered multinucleated giant cells. Immunohistochemically, 6 of 6 GSTs stained positive for vimentin, 2 of 6 for smooth muscle specific actin and 1 of 6 for desmin. At electron microscopy, GSTs showed microfilaments with focal densities as well as other smooth muscle features, such as subplasmalemmal linear densities and foci of external lamina. Ultrastructural appearances of tumor cells with clear cell features showed these not to be an artifact of fixation, but the expression of an unusual cytophagocytic activity. Inclusions of auto- and heterophagocytic nature were found responsible for the origin of the large, mostly lipidic vacuoles which displaced cell nuclei peripherally in a signet-ring fashion. It is concluded that such previously unrecognized features are ultrastructural aspects of GSTs with smooth muscle differentiation.

Gastrointestinal autonomic nerve tumors: a clinicopathological, immunohistochemical and ultrastructural study of 10 cases.

Gastrointestinal Autonomic Nerve Tumors (GANTs) are an underrecognized group of gastrointestinal stromal tumors (GISTs) putatively arising from the neural plexuses of the bowel wall. Approximately 24 cases have been previously reported. Their histogenesis, malignant potential, morphology and phenotypic features are not well defined. We present details of 10 GANTs iterating features, predominantly ultrastructural, allowing distinction from other GISTs. Clinical details are: sex-7M, 3F; age range 31-79 yrs, mean 53; symptoms/signs--abdominal pain 3, GI bleeding 3, mass 2, anemia 2. Follow-up ranged from 1-102 mths, mean 29. Seven tumors involved the small intestine and 3 were gastric. Tumor size ranged from 30-160 mm, mean 79. They were solid and cystic, often transmural and usually involved mesentery and retroperitoneum. Spindled and epithelioid cells were "compartmentalized" by a branching microvasculature. Eosinophilic, PAS positive stromal globules were prominent. Paraffin immunostaining results were (number positive/total): vimentin (8/9), NSE (10/10), S100 protein (6/10), neurofilament protein (0/9), synaptophysin (3/9), desmin (2/9, focal), smooth-muscle actin (0/9). Ultrastructural diagnostic features were elaborate, branching cytoplasmic processes containing microtubules, intermediate filaments and varying numbers of neurosecretory granules. Characteristic features were elaborate smooth endoplasmic reticulum enmeshed with intermediate filaments, pleomorphic mitochondria with lamellar cristae, mitochondrial-RER complexes, confronting RER cisternae, and circumscribed collections of stromal "skeinoid" fibres. There were no features of smooth muscle, Schwannian or perineurial differentiation.(ABSTRACT TRUNCATED AT 250 WORDS)