Fusion of the Genes PHF1 and TFE3 in Malignant Chondroid Syringoma.

BACKGROUND/AIM: Malignant chondroid syringoma is a rare tumor of unknown pathogenesis. MATERIALS AND METHODS: Genetic analyses were performed on a malignant chondroid syringoma. RESULTS: G-banding analysis of short-term cultured tumor cells yielded the karyotype 46,Y,t(X;6)(p11;p21)[15]/46,XY[2]. RNA sequencing detected an in-frame fusion of PHF1 from 6p21 with TFE3 from Xp11, verified by RT-PCR and Sanger sequencing. Genomic PCR showed that the PHF1-TFE3 junction was identical to the fusion found by RNA sequencing and RT-PCR. CONCLUSION: Malignant chondroid syringoma is genetically related to tumors with PHF1 rearrangements such as low-grade endometrial sarcoma and ossifying fibromyxoid tumor, but also with tumors having TFE3 rearrangements such as renal cell carcinoma, alveolar soft part sarcoma, PEComa, and epithelioid hemangioendothelioma. Further investigations on malignant chondroid syringomas are needed in order to determine whether genetic heterogeneity exists among them and the clinical impact of the PHF1-TFE3 fusion.

CDC73 Germline Mutation in a Family With Mixed Epithelial and Stromal Tumors.

OBJECTIVE: To describe a family in which 3 members presented with mixed epithelial tumor of the kidney (MEST) and were found to possess a germline mutation in CDC73, a gene which is associated with hyperparathyroidism-jaw tumor syndrome (HPT-JT). MATERIALS AND METHODS: Blood and tumor DNA from three family members who presented with a primary diagnosis of MEST was subjected to targeted gene sequencing to identify potential genetic components. RESULTS: A germline start codon mutation (p.M1I) in CDC73 was identified in all 3 family members who presented with MEST and 2 tumors from 1 patient demonstrated somatic copy-neutral loss of heterozygosity. Patients presented with no evidence of hyperparathyroidism or jaw tumors, but both female patients had hysterectomies at an early age due to excessive bleeding and numerous fibroids, which is common in HPT-JT. A germline p.M1I mutation has been previously reported in a family with clinical features of HPT-JT. CONCLUSION: Patients with MEST may be at risk for HPT-JT and CDC73 germline mutation testing of MEST patients should be considered.

[Histological and molecular classification of endometrial carcinoma and therapeutical implications]. / Classification histologique et moléculaire des cancers de l'endomètre et leurs implications dans la thérapeutique.

Endometrial cancer is the fourth cause of cancer in women in France and is the second most common cancer of the gynecologic cancer after breast cancer with 7275 new cases in 2012. The incidence of this neoplasm tends to increase with population aging, diabetes and obesity's augmentation. In rare cases, a hereditary factor has been described: Lynch's syndrome. The therapeutic management of the patient depends on the endometrial biopsy which specifies the histological type and the histo-prognostic grade as well as the MRI which allow the tumor staging. Within the last decade, improvement in technologies such as genomic, transcriptomic and histological analyses, allowed the establishment of new and finer classifications of endometrial carcinomas. The latest classification proposed by The Cancer Genomic Atlas (TCGA), has been made routinely applicable through the international consortium TransPORTEC. It consists of 4 groups listed from good to poor prognosis: (1) ultra-mutated "POLE"; (2) hyper-mutated "MSI"; (3) low copy number "NSMP" and (4) high number of copies "TP53 mutated" (serous-like). This integrated characterization combined with mutational data opens new opportunities for therapeutic strategies.

Overexpression of CIP2A promotes bladder cancer progression by regulating EMT

Background: Bladder cancer is the second most common urological malignancy worldwide. CIP2A is a newly identified inhibitor of PP2A. Recent studies have highlighted a potential role for CIP2A in promoting the proliferation of several cancer cells. However, the role of CIP2A in bladder cancer still remains unclear. Methods: The expression of CIP2A was detected by quantitative real-time polymerase chain reaction and IHC in bladder cancer tissues and bladder cancer cell lines. In addition, silencing of CIP2A with siRNA was performed in T24 cells, and the impact on proliferation, and apoptosis of T24 cells was analyzed. Results: Our results found that CIP2A expression levels were higher in bladder cancer tissues and cell lines. Furthermore, CIP2A siRNA significantly reduced the proliferation rate of T24 cells, induced a significant population of early and late apoptosis, and could reverse EMT in T24 cells, indicates that CIP2A expression is increased in bladder cancer and implies a role of the protein in bladder cancer progression. Conclusions: These results suggest that CIP2A is involved in tumor progression, and thus CIP2A could represent selective targets for the targeted treatments of bladder cáncer (AU)

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Lesión linfoproliferativa del saco lagrimal: caso clínico / Lacrimal sac lymphoproliferative lesion: Case report

CASO CLÍNICO: Se presenta el caso de una mujer de 51 años con tumoración firme a nivel del canto interno del ojo derecho de 5 años de evolución. La biopsia excisional mediante dacriocistectomía estableció el diagnóstico de lesión linfoproliferativa de bajo grado (hiperplasia linfoide reactiva). DISCUSIÓN: Los tumores del saco lagrimal son muy raros, con un pico de incidencia en la quinta década de la vida. La clínica en fases iniciales es parecida a la obstrucción lagrimal por otras causas, de ahí que hasta un 40% de estos tumores no se sospechen y sean diagnosticados durante la realización de una dacriocistorrinostomía

CASE REPORT: The case is presented of a 51 year-old woman with a firm mass at the medial canthus of the right eye of five years onset. A low-grade lymphoproliferative lesion (reactive lymphoid hyperplasia) was diagnosed from an excisional biopsy. DISCUSSION: Lacrimal sac tumors are rare, with a peak incidence in the fifth decade of life. The initial clinical features are epiphora and medial canthus swelling. As it mimics nasolacrimal duct obstruction, up to 40% of these tumors are misdiagnosed until undergoing surgery

Oncogene alterations in endometrial carcinosarcomas.

Endometrial carcinosarcomas are aggressive neoplasias composed of high-grade carcinomatous and sarcomatous elements. The pathogenesis and specific genetic alterations underlying these tumors are still not well known. We analyzed alterations in oncogenes involved in the pathogenesis of endometrial carcinomas that might represent predictive markers for specific therapies. Immunohistochemistry for HER2 (tyrosine kinase-type cell surface receptor HER2) and c-KIT (tyrosine-protein kinase Kit) and fluorescence in situ hybridization for EGFR (epidermal growth factor receptor) and ALK (anaplastic lymphoma receptor tyrosine kinase) were carried out for 76 endometrial carcinosarcoma samples on sequential tissue microarray sections. Analysis of 238 mutations across 19 common oncogenes was performed on 34 samples using the Sequenom OncoCarta Panel (Sequenom, Hamburg, Germany). We observed EGFR, HER2, and c-KIT expression in 71%, 1.5%, and 2.7% of tumors, respectively. EGFR amplification was detected in 11 of 76 endometrial carcinosarcomas (14.5%). Four samples showed both amplification and aneuploidy (5.2%). ALK amplification together with chromosome 2 polysomy was found in 1.3% of endometrial carcinosarcomas. In total, 23 mutations in 9 different oncogenes were detected in 15 (44.1%) of 34 endometrial carcinosarcomas. Five endometrial carcinosarcomas (14.7%) had 2 or more mutations. Eleven tumors (32.3%) had mutations affecting the PI3K (phosphoinositide-3-kinase)/AKT (v-akt murine thymoma viral oncogene homolog 1) (6 mutations in PIK3CA (PI3K catalytic alpha polypeptide) and 1 in AKT) and/or RAS/BRAF (serine/threonine-protein kinase B-raf) pathway (3 KRAS [kirsten RAS oncogene homolog], 2 NRAS [neuroblastoma RAS viral oncogene homolog], and 1 BRAF). Mutations in PDGFRA (platelet-derived growth factor receptor, alpha polypeptide) and/or KIT were found in 5 endometrial carcinosarcomas (14.7%). Finally, we found mutations in MET (met proto-oncogene [hepatocyte growth factor receptor]) in 2 tumors (5.9%) and in EGFR in one (2.9%). Our study evidences mutations in oncogenes in endometrial carcinosarcomas that are targets or modulators of response to specific therapies in other human cancers, with PI3K/AKT being the most frequently altered pathway.

Primary intraosseous myoepithelioma arising in the iliac bone and displaying trisomies of 11, 15, 17 with del (16q) and del (22q11)--A rare case report with review of literature.

Mixed tumors are uncommonly observed in the musculoskeletal system, where they form a common spectrum with a myoepithelioma and a parachordoma. Herein, we present a rare case of a mixed tumor/myoepithelioma arising in the iliac bone of a young adult male who presented with swelling in his right hip. Radiological imaging disclosed a large, intraosseous, lytic, heterogenous mass with a soft tissue component. Biopsy and subsequent tumor resection showed an 18cm sized tumor involving the iliac bone and soft tissues and comprising polygonal and spindly cells, arranged in cords and aggregates, embedded in a myxohyaline stroma with osteochondroid differentiation. Tumor cells exhibited mild nuclear variation, rare mitotic figures, focal cytoplasmic clearing, and prominent squamous differentiation. On immunohistochemistry (IHC), tumor cells were diffusely positive for S100-P, EMA, CK5/6, p63, GFAP, calponin, and focally positive for CK/MNF116, but negative for Brachyury/T. Diagnosis of a myoepithelioma/mixed tumor was offered. Further, cytogenetic analysis revealed lack of EWSR1 gene rearrangement and showed clonal trisomies of 11, 15, 17 with del (16q) and del (22q11). The present case is a rare documentation of a myoepithelioma in the appendicular bones and the second such case identified in the iliac bone. IHC and cytogenetic findings supported a myoepithelial cell origin, and reinforced its relationship with a parachordoma and its distinction from mixed salivary gland tumors, a chordoma, and an extraskeletal myxoid chondrosarcoma that form its differential diagnoses.

Mixed epithelial and stromal tumors of the kidney: evidence for a single cell of origin with capacity for epithelial and stromal differentiation.

Mixed epithelial and stromal tumors are uncommon biphasic tumors of the kidney, with cystic and solid areas composed of a morphologically diverse stroma, including ovarian-like stroma and an epithelial component with considerable heterogeneity. Little is known about the histogenesis and clonal origins of these tumors. A total of 21 mixed epithelial and stromal tumors of the kidney from female patients who underwent radical or partial nephrectomies were examined. The epithelial and stromal components, and also adjacent non-neoplastic renal parenchymal tissues were separately laser microdissected from sections prepared from formalin-fixed and paraffin-embedded tissues for X chromosome inactivation analysis. Nineteen of the 21 tumors were informative. Seven of these informative cases showed random X chromosome inactivation pattern in both epithelial and stromal components of mixed epithelial and stromal tumors of the kidney. Nonrandom inactivation of the X chromosome was found in 12 of 19 informative tumors. The same pattern of nonrandom inactivation of the X chromosome was seen in both epithelial and stromal components in all 12 of the tumors with nonrandom X chromosome inactivation. Our data support the theory that the stroma and epithelium arise from a common cell of origin.

Thyroid carcinoma with papillary and squamous features: report of a case with histogenetic considerations.

We present a case of an 82-year-old female with a painless left latero-cervical swelling, which increased in size over the course of 6 months, compressing adjacent organs. The histopathological examination, following dissection of the left thyroid lobe and ipsilateral cervical lymph nodes, yielded two intermingled morphologically distinct histotypes that included conventional papillary thyroid carcinoma (PTC) and poorly differentiated squamous cell carcinoma (SCC) with cystic features. The clinical presentation, the immunophenotype, and the genotype, especially of the malignant squamous component with partial expression of TTF1, marked expression of p63 and mutation of BRAF, were consistent with the diagnosis of a papillary thyroid carcinoma with squamous component. The possibility of a squamous cell carcinoma of unknown origin metastasizing to a primary papillary thyroid carcinoma cannot be completely ruled out. This particular presentation of thyroid carcinoma carries a poor prognosis in 20% of cases, with high recurrence rates and distant metastasis.

Minimally invasive adenocarcinomas of the lung.

Current World Health Organization (WHO) classification of lung adenocarcinomas includes noninvasive bronchioloalveolar carcinoma (BAC) and several patterns of invasive adenocarcinoma. The most common is a mixed subtype of adenocarcinoma. This group is very heterogenous and includes a wide spectrum of tumors ranging from adenocarcinomas with a dominant BAC growth pattern (lepidic growth) to frankly invasive adenocarcinoma with no BAC component. There is a tendency among clinicians to regard tumor as BAC if any significant amount of lepidic growth pattern within the tumor is identified. The change in WHO definition of BAC and introduction of mixed subtype of adenocarcinoma resulted in disconnect between surgical pathologists and clinicians regarding the use of terminology and criteria for diagnosis of BAC and mixed subtype of adenocarcinoma. It is clear that pure BAC is an extremely rare tumor, whereas mixed subtypes of adenocarcinomas may have various clinical presentations and outcomes. The mounting evidence suggests that a subset of mixed subtype of adenocarcinomas with areas of BAC and focal invasion probably represent more indolent tumors. On the basis of the published data, there is a proposal to define a subcategory of "minimally invasive adenocarcinoma" of the lung. Many morphologic factors seem to play a role in predicting the behavior of these tumors. Depending on the results of ongoing clinical trials, surgical management of these tumors may change in a near future.

Optimization of methods to assess mitochondrial DNA in archival paraffin-embedded tissues from mammary canine tumors / Otimização dos métodos para avaliar o DNA mitocondrial obtido a partir de tumores mamários caninos incluídos em parafina

In this study we describe the alterations used to extract and amplify mitochondrial desoxyribonucleic acid (DNA) from formalin-fixed paraffin-embedded samples of canine mammary tumors. The epithelial and mesenchymal components (chondromyxoid and chondroid) of each tumor, as well as the normal mammary gland tissues, were manually microdissected from 19 mixed canine mammary tumors (10 benign mixed tumors and nine carcinomas arising in mixed tumors). DNA was extracted by Invisorb® Spin Tissue Mini Kit, with protocol changes proposed by the manufacturer. A 273-bp fragment was amplified by polymerase chain reaction (PCR) and submitted to automatic sequence analysis. The fragment was successfully analyzed in 100 percent of the samples. However, an additional lysis step, the reduction of volume in buffer solutions and PCR, a higher annealing temperature and an increase in the number of PCR cycles were required. The initial PCR products were diluted and re-amplified in six samples so that they could be successfully analyzed.

A presente comunicação descreve as modificações usadas para extrair e amplificar o DNA mitocondrial obtido de amostras de tumores mamários caninos fixados em formol tamponado a 10 por cento e incluídos em parafina. Os componentes epiteliais e mesenquimais (condromixóide e condróide), bem como a mama normal adjacente, foram microdissectados manualmente de 19 tumores mamários (10 tumores mistos benignos e nove carcinomas em tumores mistos). O DNA foi extraído utilizando-se o Invisorb® Spin Tissue Mini Kit com modificações do protocolo proposto pelo fabricante. Um fragmento de 273-pb foi amplificado por reação em cadeia da polimerase (PCR) e seqüenciado em seqüenciador automático. O fragmento foi analisado em 100 por cento das amostras, entretanto modificações como lise adicional, redução do volume das soluções de extração e PCR, aumento da temperatura de anelamento e do número de ciclos de amplificação foram necessárias. Em seis amostras os produtos iniciais de PCR foram diluídos e reamplificados para obtenção de sucesso.

Papillary renal cell carcinoma within a renal oncocytoma: case report of an incidental finding of a tumour within a tumour.

The most common renal tumours are clear cell, papillary, chromophobe and collecting duct renal cell carcinomas (RCCs), and benign oncocytomas and angiomyolipomas. Tumours with hybrid features between some of these entities have been recognised; in particular, tumours with features of both chromophobe RCC and oncocytoma. Case reports describing one distinct type of primary renal tumour actually within another are very rare. The incidental finding of a papillary RCC located in an oncocytoma in a nephrectomy specimen from a 75-year-old man is described. Morphological criteria for each tumour type were completely satisfied and fluorescence in situ hybridisation detected the expected number of copies of chromosome 7 in the cells of each tumour type. The cells in the papillary tumour contained three copies, whereas the oncocytoma cells contained only two per nucleus. To our knowledge, this is the first report of a papillary RCC being identified within an oncocytoma.

Transformed dermatofibrosarcoma protuberans: real time polymerase chain reaction detection of COL1A1-PDGFB fusion transcripts in sarcomatous areas.

BACKGROUND: Recent cytogenetic studies have shown that reciprocal translocation t (17;22)(q22;q13) and a supernumerary ring chromosome derived from the translocation r(17;22) are highly characteristic of dermatofibrosarcoma protuberans (DFSP). The chromosomal rearrangements fuse the collagen type Ialpha1 (COL1A1) and the platelet-derived growth factor B-chain (PDGFB) genes. The COL1A1-PDGFB fusion transcript has been shown not only in conventional DFSP but also in a small series of DFSP with fibrosarcomatons areas (DFSP-FS) using reverse transcriptase-based conventional polymerase chain reaction. Nothing is known about the status of the COL1A1-PDGFB chimaeric gene in the pleomorphic areas of DFSP-PleoSarc (formerly known as DFSP-malignant fibrous sarcoma). AIMS: To show the COL1A1-PDGFB fusion transcript in transformed malignant fibrous histiocytoma. METHOD: A real-time polymerase chain reaction assay for the COL1A1-PDGFB fusion transcript in a series of DFSP containing sarcoma was conducted to determine whether the chimaeric gene could be identified in both components of DFSP-FS and DFSP-PleoSarc. Eight cases were analysed. RESULTS: In seven cases, transcriptable RNA was detected, and in these cases, translocations were found between COL1A1 and PDGFB genes involving exons 27, 32, 34, 40 and 47 of the COL1A1 gene and exon 2 of the PDGFB gene. CONCLUSIONS: From a diagnostic aspect, this assay can be particularly useful in confirming the diagnosis of sarcomatous DFSP. On the other hand, the COL1A1-PDGFB fusion gene was shown in three cases of DFSP containing pleomorphic sarcoma, which supports the theory of the common histogenesis.

Malignant mixed tumors of the salivary gland: a study of loss of heterozygosity in tumor suppressor genes.

Carcinosarcomas and carcinoma ex pleomorphic adenoma of the salivary glands are rare tumors that fit into the broader category of malignant mixed tumors. Although most evidence has suggested that the different morphologic components arise from a common clonal origin, there are very few studies that have provided molecular evidence for this clonality. In this study, we examined a set of seven carcinosarcomas and four carcinomas ex pleomorphic adenoma for tumor suppressor gene loss of heterozygosity, in order to assess the clonal patterns in the varying components. Microdissection was performed to obtain each morphological component and tumor suppressor gene loci on 3p, 5q, 9p, 17p, 17q, and 18q were analyzed. The fractional allelic loss (FAL) was calculated for each area, and the different targets were compared for their molecular profile. The overall mean FAL of the malignant targets was 42%. In carcinosarcomas, the sarcomatous targets had a higher mean FAL than the carcinomatous targets (68 vs 46%, respectively) and in carcinomas ex pleomorphic adenoma, the mean FAL in the benign component was 11 vs 46% seen in the carcinomatous component. The most frequently lost genetic loci were p53 (17p13, 73%), nm23-H1 (17q21, 55%), and DCC (18q21, 50%). Loss of heterozygosity of 17q21 and 9p21 only occurred in carcinosarcomas and not in carcinomas ex pleomorphic adenoma. Within the carcinosarcomas, the mutational profiles were conserved between epithelial and sarcomatous areas. In carcinomas ex pleomorphic adenoma, loss of heterozygosity was uncommon in the benign component, but the mutations were conserved in the corresponding malignant areas. These results support the hypothesis that the carcinomatous and sarcomatous components of carcinosarcomas are clonally related. Furthermore, these data support prior studies that suggest a common clonal origin for the benign and malignant components of carcinomas ex pleomorphic adenoma.

[Perineuriomas and other tumors with perineurial differentiation].

This is a review of the literature on the peripheral nerve sheath tumors with perineural differentiation. The authors provide an overview of the clinicopathological, immunohistochemical, ultrastructural, and genetic features of these neoplasms. Emphasis is laid on various morphological variants of perineurioma (intraneural, retifrm, sclerosing, plexiform, atypical, malignant, etc.) and so-called hybrid tumors (schwannoma-perineurioma, neurofibroma-perineurioma).

Meningiomas of the basal posterior fossa. Surgial experience in 80 cases / Meningiomas basales de la fosa posterior. Experiencia quirúrgica con 80 casos

Introduction. Despite recent imporvements in microsurgical and radiotherpay techniques, treatment of basal posterior fossa meningiomas still carries an elevated risk of morbidity. We present our results in a series of patients with this type of tumor and review the recent literature looking for the results obtained with different approaches and the new tendencies and algorithms proposed for managing these challenging lesions. Material and Methods: We analyzed retrospectively the clinical presentation and outcome of 80 patients consecutively operated between 1979 and 2003 for basal posterior fossa meningioma (foramen magnum tumors excluded). All patients had preoperative CT scans and the majority MRI studies. A total of 114 operations were performed including two-stage operations, reoperation for recurrence, CSF diversion, and XII-VII anastomosis. The most commonly used approaches were lateral suboccipital retrosigmoid, subtemporal-transtentorial, frontotemporal pterional and supra-infratentiorial presigmoid. Thirteen patients received postoperative radiotherapy. Results. There were 50 (73,7%) women and 21 men (mean age = 51,5 years; range = 18-78 yrs). Most common presenting symptoms were ranial nerve dysfunction, gait disturbances and intracranial hypertenseion. The mena duration of symptoms was 2.9 years. 70% of the tumors were over 3 cm in size. Fifty patients (62,5%) had a complete resection, 22 (27,5%) subtotal resection (> 90% tumor volume removed), and 8 (10%) only partial resection. Postoperative complications included hematoma, CSF leak, and infection. Fifty four (67,5%) patients developed new or increased cranial nerve deficits and 12,5% somatomortor, somatosensory or cerebellar deficits immediately after surgery with subsequent improvement in most cases. Following initial surgery 67 patients made a good recovery, 10 developed variable degrees of disability and 3 died (…) (AU)

Introducción: A pesar de la técnica microquirúrgica y la disponibilidad de la radioterapia estereotáxica, el tratamiento de los meningiomas de la base craneal todavía conlleva un riesgo elevado de morbilidad. Se presenta una serie de pacientes con meningiomas básales de la fosa posterior y se revisa la literatura para establecer una comparación de los resultados obtenidos con diferentes tipos de abordaje terapéutico y detectar las nuevas tendencias para el manejo de estos tumores. Material y métodos: Se analizaron de modo retrospectivo la presentación y evolución clínica de 80 pacientes operados consecutivamente entre 1979 y 2003 por vía intradural de meningiomas localizados en la base de la fosa posterior (excluidos los del foramen magno). Se practicó TAC craneal en todos los casos y RM en la mayoría. Se realizaron 114 intervenciones, incluyendo operación en dos estadios, reoperación por recurrencia, derivaciones de LCR y anastomosis VII-XII. Los abordajes más empleados fueron el lateral suboccipital retrosigmoideo, subtemporal-transtentorial, frontotemporal pterional y supra-infratentorial presigmoideo retrolaberíntico. 13 pacientes recibieron además tratamiento radioterápico. Resultados: Se trataron 59 mujeres (73.7%) y 21 hombres (edad media = 51.5 años; rango = 18–78). Los síntomas más frecuentes de presentación (duración media de la historia = 2,9 años) fueron alteraciones de los pares craneales, cefaleas y alteraciones de la marcha. 70% de los tumores tenían un diámetro mayor superior a 3cm. La extirpación fue completa en 50 casos (62.5%), subtotal (resección > 90% del volumen tumoral) en 22 (27.5%) y parcial en 8 (10%). Las complicaciones postoperatorias incluyeron hematoma, fístula LCR, e infección. 54 (67.5%) pacientes desarrollaron incremento, o nueva afectación de pares craneales y un 12.5% déficits de vías largas o cerebelo que mejoraron posteriormente en la gran mayoría. Tras la primera operación 67 pacientes hicieron una buena recuperación, 10 desarrollaron diferentes grados de incapacidad y 3 fallecieron. Once pacientes fallecieron tardíamente durante el curso por recurrencia tumoral con o sin reoperación, meningioma maligno, o causas no relacionadas. Se registraron 9 recurrencias tras resección inicial aparentemente completa (seguimiento medio = 8.6 años). La mayoría de los pacientes con resección subtotal y parcial se han manejado sin reoperación durante un periodo medio de 6.5 años (radiocirugía y/u observación). Discusión y Conclusiones: La técnica microquirúrgica y la radioterapia estereotáxica permiten un control aceptable de estos meningiomas. En los pacientes con invasión del seno cavernoso, extensión extracraneal, transgresión del plano aracnoideo en relación con el tronco cerebral, o adherencia a arterias cerebrales y sus perforantes, la extirpación subtotal parece preferible. En la planificación del tratamiento, se deben considerar además la edad del paciente, la presentación clínica (lesión sintomática o no sintomática), así como el tamaño y la extensión del tumor (AU)

Microdissection genotyping of mixed glial and primitive neuroectodermal central nervous system neoplasm.

A 22-year-old man with previous radiation treatment for childhood astrocytoma underwent resection of a right parietooccipital lesion. Histopathology revealed a malignant neoplasm with areas of astrocytic and primitive neuroectodermal components. To resolve the relationship and cellular origin, representative tissue was microdissected from several targets, obtaining a balanced mixture of each element. Nonneoplastic brain parenchyma was separately microdissected to determine polymorphic marker informativeness and to serve as an internal negative control. Despite the relatively small quantity of tissue removed for each microdissection target, sufficient material was available for reliable, balanced, polymerase chain reaction-format genotyping encompassing a panel of tumor suppressor genes and genetic loci associated with these forms of neoplasia. The findings revealed distinct discordant genotypic profiles for each of the neoplastic components. The efficacy of the approach used for molecular analysis of this complex neoplasm and the implication of the genotypic findings are discussed.