Patterns of chromosomal imbalances in benign solitary fibrous tumours of the pleura

Solitary Fibrous Tumor of Breast with Anaplastic Areas (Malignant Solitary Fibrous Tumor): A Case Report with Review of Literature

Solitary fibrous tumor (SFT) is a rare, soft tissue neoplasm that rarely presents in breast tissue, with only 27 previously reported cases. To our knowledge, only one case of malignant SFT has been reported in the English literature. A 75-year-old Caucasian woman presented to our institution with a 3-month history of a palpable left breast mass. No other symptoms, including nipple discharge or skin changes, were noted. She underwent 3 previous biopsies for right breast masses, all of which were benign, with no evidence of spindle cell neoplasm, atypical hyperplasia, or malignancy. Microscopic examination of the mass demonstrated a classic area of SFT with areas of high-grade anaplastic component. In these areas, the tumor showed atypical epithelioid cells arranged in hypercellular sheets with diminished branching vasculature, nuclear pleomorphism, and increased mitotic count (up to 9/10 high-power fields). This case represents the second case of malignant SFT in the breast.

Patient-Derived Xenograft Establishment from Human Malignant Pleural Mesothelioma

Purpose: Malignant pleural mesothelioma (MPM) is a rare but aggressive disease with few therapeutic options. The tumor-stromal interface is important in MPM, but this is lost in cell lines, the main model used for preclinical studies. We sought to characterize MPM patient-derived xenografts (PDX) to determine their suitability as preclinical models and whether tumors that engraft reflect a more aggressive biological phenotype.Experimental Design: Fresh tumors were harvested from extrapleural pneumonectomy, decortication, or biopsy samples of 50 MPM patients and implanted subcutaneously into immunodeficient mice and serially passaged for up to five generations. We correlated selected mesothelioma biomarkers between PDX and patient tumors, and PDX establishment with the clinical pathologic features of the patients, including their survival. DNA of nine PDXs was profiled using the OncoScan FFPE Express platform. Ten PDXs were treated with cisplatin and pemetrexed.Results: A PDX was formed in 20 of 50 (40%) tumors implanted. Histologically, PDX models closely resembled the parent tumor. PDX models formed despite preoperative chemotherapy and radiotherapy. In multivariable analysis, patients whose tumors formed a PDX had significantly poorer survival when the model was adjusted for preoperative treatment (HR, 2.46; 95% confidence interval, 1.1-5.52; P = 0.028). Among 10 models treated with cisplatin, seven demonstrated growth inhibition. Genomic abnormalities seen in nine PDX models were similar to that previously reported.Conclusions: Patients whose tumors form PDX models have poorer clinical outcomes. MPM PDX tumors closely resemble the genotype and phenotype of parent tumors, making them valuable models for preclinical studies. Clin Cancer Res; 23(4); 1060-7. ©2016 AACR.

Solitary fibrous tumors: loss of chimeric protein expression and genomic instability mark dedifferentiation

Solitary fibrous tumors, which are characterized by their broad morphological spectrum and unpredictable behavior, are rare mesenchymal neoplasias that are currently divided into three main variants that have the NAB2-STAT6 gene fusion as their unifying molecular lesion: usual, malignant and dedifferentiated solitary fibrous tumors. The aims of this study were to validate molecular and immunohistochemical/biochemical approaches to diagnose the range of solitary fibrous tumors by focusing on the dedifferentiated variant, and to reveal the genetic events associated with dedifferentiation by integrating the findings of array comparative genomic hybridization. We studied 29 usual, malignant and dedifferentiated solitary fibrous tumors from 24 patients (including paired samples from five patients whose tumors progressed to the dedifferentiated form) by means of STAT6 immunohistochemistry and (when frozen material was available) reverse-transcriptase polymerase chain reaction and biochemistry. In addition, the array comparative genomic hybridization findings were used to profile 12 tumors from nine patients. The NAB2/STAT6 fusion was detected in all of the tumors, but immunohistochemistry and western blotting indicated that chimeric protein expression was atypical or absent in 9 out of 11 dedifferentiated tumors. The comparative genomic hybridization results revealed that the usual and malignant solitary fibrous tumors had a simple profile, whereas the genome of the dedifferentiated tumors was complex and unstable, and suggested that 13q and 17p deletions and TP53 mutations may be present in malignant lesions before the full expression of a dedifferentiated phenotype. Solitary fibrous tumor dedifferentiation is associated with the loss of chimeric oncoprotein expression, genomic instability, and cell decommitment and reprogramming. The assessment of dedifferentiated solitary fibrous tumors is based on the presence of the fusion transcripts and, in principle, negative STAT6 immunohistochemistry should not rule out a diagnosis of solitary fibrous tumor.

Gene expression profiling of solitary fibrous tumors

Background

Solitary fibrous tumors (SFTs) are rare spindle-cell tumors. Their cell-of-origin and molecular basis are poorly known. They raise several clinical problems. Differential diagnosis may be difficult, prognosis is poorly apprehended by histoclinical features, and no effective therapy exists for advanced stages.

Methods

We profiled 16 SFT samples using whole-genome DNA microarrays and analyzed their expression profiles with publicly available profiles of 36 additional SFTs and 212 soft tissue sarcomas (STSs). Immunohistochemistry was applied to validate the expression of some discriminating genes.

Results

SFTs displayed whole-genome expression profiles more homogeneous and different from STSs, but closer to genetically-simple than genetically-complex STSs. The SFTs/STSs comparison identified a high percentage (∼30%) of genes as differentially expressed, most of them without any DNA copy number alteration. One of the genes most overexpressed in SFTs encoded the ALDH1 stem cell marker. Several upregulated genes and associated ontologies were also related to progenitor/stem cells. SFTs also overexpressed genes encoding therapeutic targets such as kinases (EGFR, ERBB2, FGFR1, JAK2), histone deacetylases, or retinoic acid receptors. Their overexpression was found in all SFTs, regardless the anatomical location. Finally, we identified a 31-gene signature associated with the mitotic count, containing many genes related to cell cycle/mitosis, including AURKA.

Conclusion

We established a robust repertoire of genes differentially expressed in SFTs. Certain overexpressed genes could provide new diagnostic (ALDH1A1), prognostic (AURKA) and/or therapeutic targets.

Solitary fibrous tumor: is there a molecular relationship with cellular angiofibroma, spindle cell lipoma, and mammary-type myofibroblastoma?

Solitary fibrous tumor (SFT) is a mesenchymal tumor characterized by ovoid cells, branching blood vessels, stromal hyalinization, and CD34 immunoreactivity. Studies have shown loss of 13q in a group of morphologically similar entities, including cellular angiofibroma, mammary-type myofibroblastoma, and spindle cell lipoma. The histologic and immunophenotypic overlap between SFT and the latter group of tumors suggests that these tumors may be genetically linked. We tested a group of 40 SFTs to assess for loss of RB1 (13q14) by fluorescence in situ hybridization (FISH). All 38 SFTs with evaluable signals failed to show loss of RB1 (13q14) by FISH. All cases of cellular angiofibroma (1/1), spindle cell lipoma (6/6), and mammary-type myofibroblastoma (4/4), which were used as a control group, showed monoallelic or biallelic loss of RB1. The absence of RB1 loss in SFTs suggests that they are not related to cellular angiofibroma, mammary-type myofibroblastoma, or spindle cell lipoma.

Oral solitary fibrous tumor: a cytogenetic analysis of tumor cells in culture with literature review

Solitary fibrous tumor (SFT) is an uncommon spindle-cell neoplasm of mesenchymal origin. Because the pathogenetic background of SFT is still controversial, cytogenetic analysis could help in tumor diagnosis and prognosis. In this study, cultured SFT cells from a lower lip lesion that presented characteristic immunopositivity for CD34, vimentin, CD99, and BCL2 showed a unique cytogenetic finding: 46,XX,inv(2)(p21q35),t(3;12)(q25;q15). To our knowledge, this is the third report of cytogenetic result of a case involving the oral cavity. The SFT cells in culture that maintained their immunohistochemical expression of diagnostic molecules, showed unique chromosomal changes previously unreported when compared with already documented ones. Our data suggest that the complicated pathogenetic nature of SFT is possibly tumor- or organ-related.

New insights into the hemangiopericytoma/solitary fibrous tumor spectrum of tumors

PURPOSE OF REVIEW

This review provides an overview of the hemangiopericytoma/solitary fibrous tumor (HPC/SFT) spectrum of tumors, focusing on the histopathologic characteristics, clinical features, diagnosis, and treatment of HPC/SFT.

RECENT FINDINGS

Due to the relatively insensitive nature of HPC/SFT to radiotherapy and cytotoxic chemotherapy, new therapies are needed for treatment of advanced disease. Inhibition of angiogenic pathways may provide a novel therapeutic mechanism for targeting this malignancy. Combination therapy with temozolomide and bevacizumab has recently emerged as a potentially promising regimen for HPC/SFT.

SUMMARY

With many novel targeted therapies currently in development for soft tissue sarcomas, a better understanding of the molecular pathogenesis and aberrations of HPC/SFT is needed to determine optimal therapeutic agents. Identifying appropriate targets and designing rational prospective clinical trials will not only improve treatment of HPC/SFT but will also lead to a new paradigm of personalized, targeted therapy.

Cytogenetic, fluorescence in situ hybridization, and immunohistochemistry studies in a malignant pleural solitary fibrous tumor

Pleural solitary fibrous tumor is a normally benign fibroblastic neoplasm; its recurrences and metastasis are associated with clinical and morphological characteristics of variable interpretation and efficacy of surgical treatment. Immunohistochemistry techniques have contributed decisively to the correct diagnosis of the lesion and define its prognosis. In the present case, cytogenetic and fluorescence in situ hybridization analyses revealed multiple chromosomal aberrations, including a del(9)(q21qter) and a marker chromosome ish der(9)(ABL+). The present data support but do not resolve the possible involvement of a gene on 9q22 in the biological behavior of these tumors, and the ABL rearrangements and deletions of 1p and 10p suggest another possible malignant component.

Solitary fibrous tumor of the larynx

BACKGROUND

True mesenchymal, non-cartilaginous neoplasms of the larynx are rare. Extrapleural solitary fibrous tumor (SFT) is a localized neoplasm characterized by proliferation of thin-walled vessels and collagen-producing cells and is considered within the "hemangiopericytoma-solitary fibrous tumor" spectrum. SFT primary in the larynx is exceptional.

DESIGN

Case report set in a comparison with other cases reported in the English literature (MEDLINE 1966 to 2007).

RESULTS

A 49-year old white male presented with difficulty breathing, progressive over the past 2 years. He denied dysphagia and weight loss. Past medical history was significant for asthma. He denied cigarette smoking or alcohol abuse. There were no cervical deformities on physical exam. Fiberoptic laryngoscopy was performed upon stabilization of respiratory function. A smooth, round, submucosal mass measuring 2.3 cm in greatest diameter arising from the inferior surface of left true vocal cord was causing near total obstruction of the endolaryngeal space. The mass was excised. The surface mucosa was intact and unremarkable. A cellular, spindle cell neoplasm was arranged in loose fascicles, associated with heavy collagen fiber deposition. The collagen was wiry and heavy. Cells were bland with cytoplasmic extensions. The nuclei were vesicular to hyperchromatic and elongated with inconspicuous nucleoli. Vessels were prominent and delicate, with patulous spaces. Mitotic figures were easily identified, but atypical forms were not present. The cells were strongly and diffusely immunoreactive with CD34 and bcl-2, while non-reactive with cytokeratin, EMA, actin, ALK-1, S100, desmin, and CD117. These findings confirmed a diagnosis of extraplural solitary fibrous tumor. Without further disease, the patient is alive without evidence of disease, 12 months after surgery.

CONCLUSIONS

The characteristic histologic pattern of solitary fibrous tumor can be noted in extrapulmonary locations. Development in the larynx is uncommon, but the tumor presents as a polypoid mass with characteristic histologic and immunophenotypic features. Conservative local excision is the treatment of choice to yield an excellent prognosis.

Lack of a common or characteristic cytogenetic anomaly in solitary fibrous tumor

Solitary fibrous tumor is a mesenchymal tumor that was initially described as a pleural-based lesion, but later was discovered in many other locations. The light-microscopic appearance of solitary fibrous tumor may overlap with other diagnostic entities; however, consistent tumor cell CD34 immunoreactivity is useful in establishing the diagnosis. Limited data suggest that solitary fibrous tumors are karyotypically diverse, and no common or characteristic anomaly has yet emerged for this entity. Cytogenetic analysis of two solitary fibrous tumors, one peritoneal and the other arising in the liver, revealed predominantly structural abnormalities in the former and numerical imbalances in the latter. Clonal karyotypic abnormalities were lacking in three additional solitary fibrous tumors.

A clonal t(8;12)(p11.2;q24.3) as the sole abnormality in a solitary fibrous tumor of the pleura

A case of solitary fibrous tumor of the pleura with the karyotype 46,XY,t(8;12)(p11.2;q24.3) is reported. Although rearrangement of 12q15 approximately 24 is a recurring abnormality in solitary fibrous tumors, rearrangement of chromosome 8 was previously unreported in these tumors.

Solitary fibrous tumor of the orbit: Morphological, cytogenetic and molecular features

Solitary fibrous tumor (SFT), a benign neoplasm arising in mesenchymal structures, was initially described in the pleura but subsequently has also been documented in other locations. It is uncommon in the orbit, where it closely resembles other benign spindle-shaped mesenchymal tumors of this area such as schwannoma, meningioma or hemangiopericytoma. We present a case of orbital SFT in a 34-year-old woman. The radiological study showed the presence of an enhanced uptake lesion measuring 2 cm in major diameter. The histopathological evaluation revealed alternating cellular and hypocellular areas with spindle-shaped cells. The cellular organization displayed a broad variety of irregular morphological patterns. The neoplastic cells were intensely positive for CD34 and vimentin, while S100, epithelial membrane antigen (EMA), Caldesmon, Calretinin and WT-1 proved negative. The pericellular matrix exhibited strong positivity for CD44 and collagen IV. Scarce mitotic figures, a Ki-67 nuclear labeling index of <5%, and focal expression of p53 were also observed. Measurement of DNA content revealed a DNA index of 1, indicating a diploid peak in 95% of the tumor cells. A normal 46,XX karyotype was present. No TP53 (exons 5-8) mutations or MDM2 and CDK4 amplifications were observed. No p14(ARF), p15(INK4B) and p16(INK4A) deletions or hypermethylation were observed in this benign tumor. Following surgical resection and radiotherapy, the patient showed no tumor relapse after one year of follow-up.

Cytogenetic and molecular genetic changes in malignant mesothelioma

Malignant mesothelioma (MM) results from the accumulation of a number of acquired genetic events, especially deletions, which lead to the inactivation of multiple onco-suppressor genes in a multistep cascade mechanism. Past asbestos exposure represents the major risk factor for MM, and the link between asbestos fibers and MM has been largely proved by several epidemiologic and experimental studies. Asbestos fibers induce DNA and chromosomal damage. Most MM cases have shown multiple chromosomal abnormalities. Chromosomal losses are more common than gains. The most common cytogenetic abnormality in MM is a deletion in 9p21, the locus of CDKN2A, a tumor suppressor gene (TSG). The deletion of CDKN2A is a negative prognostic factor in MM. Loss of TSG CDKN2A/p14(ARF) is also common in MM and mutations in NF2 occur in approximately half of the cases. Despite the ban on asbestos use in Western countries, the incidence of MM is increasing, and asbestos is still used in developing countries. This epidemiologic situation calls for further research. Ongoing studies are already applying high-throughput genomic profiling methods in MM. Genetic alterations observed in MM may be useful in differential diagnosis between lung cancer and MM, as diagnostic markers or therapeutic targets, and as indicators of premalignancy for primary prevention and health surveillance.

Sclerosing pseudovascular rhabdomyosarcoma-immunohistochemical, ultrastructural, and genetic findings indicating a distinct subtype of rhabdomyosarcoma

Sclerosing (pseudovascular) rhabdomyosarcoma in adults has been described as a rare variant of rhabdomyosarcoma characterized by extensive hyaline fibrosis and pseudovascular growth patterns. We describe another case of this rhabdomyosarcoma subtype including ultrastructural and genetic findings-the lesion presented in a 62-year-old male patient in the left lower leg. The tumor was located within the deep soft tissue with maximum diameter of 11.8 cm and skin ulceration. Ultrastructural analysis revealed irregularly distributed disorganized filaments without clear evidence of Z-bands and a richly collagenized matrix. Using comparative genomic hybridization, a sharply delineated loss of chromosomal region 10q22, loss of chromosome Y, and a gain of chromosome 18 (trisomy) were detected. Reciprocal translocations t(1;13) and t(2;13)(q35;q14) which are characteristic of alveolar rhabdomyosarcoma could be excluded. These findings, while showing a relation to other rhabdomyosarcoma subtypes, represent a relatively circumscribed genetic defect pattern in sclerosing (pseudovascular) rhabdomyosarcoma that is somewhat different from patterns described in most other rhabdomyosarcoma subtypes. Six months after tumor resection, the patient presented with metastatic disease. Further studies should concentrate on the identification of genes especially on chromosomal region 10q22 to elucidate more aspects in the pathogenesis of this rhabdomyosarcoma subtype.

Chromosomal imbalances in a recurrent solitary fibrous tumor of the orbit

Using comparative genomic hybridization (CGH), array CGH, fluorescence in situ hybridization, and loss of heterozygosity analysis, we examined a recurrent solitary fibrous tumor of the orbit for chromosomal imbalances. In the primary tumor, loss of chromosomal material was observed at 9p, 9q, and 16q. In the first recurrent tumor, cells with these abnormalities were detected, but in some parts of the tumor, cells with losses at 13q (homozygous deletion at 13qter) and 20p were dominant. In the second recurrence, only cells with losses at 13q and 20p were seen. Although morphologically similar, the second recurrent tumor invaded the anterior cranial fossa and demonstrated considerably faster growth than the first recurrent tumor. Thus, the clone of tumor cells that dominated the second recurrent tumor was shown by cytogenetic analysis to be different from that present in the primary tumor, and was associated with a more aggressive nature of the tumor.

Spindle cell tumours of the pleura: a clinical, histological and comparative genomic hybridization analysis of 14 cases

We examined 14 spindle cell tumours of the pleura that were sent to a Mesothelioma Panel for re-evaluation after a primary suspicion of mesothelioma. The clinical, histological, immunohistochemical and CGH findings were investigated. Final diagnoses were eight sarcomatoid mesotheliomas (SM) and six non-mesotheliomas: two pulmonary sarcomatoid carcinomas, an epithelioid hemangioendothelioma, a malignant solitary fibrous tumour, a malignant pleural smooth muscle tumour and an extraskeletal osteosarcoma. Seven of the eight SM and two of the other six tumours presented with unilateral pleural effusion, dyspnoea, and chest pain, which are characteristic clinical findings in malignant mesothelioma. No single antibody used in the immunohistochemistry separated SM from other tumour types. The most frequently observed chromosomal losses in SM were 4q, 4p11-p13/p15, 6q and 13. Losses of 4p11-p13/p15 and 4q occurred in combination in four out of five SM with detectable chromosomal changes, but neither was found in any of the other tumours. Gain or high-level amplification of 5p was also common in SM. According to our results and literature, losses at 4p, 4q and 9p and gain at 5p are the chromosomal changes that best differentiate SM from pleural sarcomas and lung carcinomas. CGH analysis may help distinguish a cytokeratin-positive SM from a sarcomatoid carcinoma. Similarly, in the case of a cytokeratin-negative tumour, CGH analysis may disclose chromosomal changes characteristic of sarcomas or mesotheliomas.

[Myoepithelioma of soft tissue -- case report with clinicopathologic, ultrastructural, and cytogenetic findings]

The case of a soft tissue myoepithelioma is presented including clinicopathologic, ultrastructural, and genetic findings. A 30-year-old male patient suffered from a soft tissue tumor within the deep soft tissues of the right lower leg measuring 13.2 x 8.2 x 9 cm. Histologically, the lesion was diagnosed as a myoepithelioma displaying a lobulated architecture with cords and nests of epithelioid and spindle cells without cytologic atypia lying within a fibromyxoid and partly chondroid matrix; immunohistochemistry was positive for pancytokeratin, S100-protein, calponin and partly for GFAP and EMA. Ultrastructural analysis revealed glycogen deposits and cell-membrane-associated plaque structures, whereas true myofilaments could not be identified (with immunohistochemistry being negative for actin). Using comparative genomic hybridization (CGH), a gain of chromosome Y was detected. A loss on 17p could not be detected unambiguously. However, based on the low resolution of CGH a small loss cannot be excluded. The patient was free of disease 25 months following complete tumor resection. Myoepitheliomas/mixed tumors of deep soft tissue represent rare soft tissue lesions that may reach a considerable size and may mimic other soft tissue tumors or sarcomas. Based on a local relapse rate of approximately 20% according to the literature, a complete resection with thorough follow-up should be recommended.

Chromosomal alterations in early stages of malignant mesotheliomas

In a case of a 67-year-old man with two different early stages of a predominantly epithelioid mesothelioma ("mesothelioma in situ", "early-stage mesothelioma"), chromosomal imbalances were determined by comparative genomic hybridisation (CGH), a molecular cytogenetic technique to detect chromosomal gains and losses in tumour cells. In the case of the mesothelioma in situ cells, nine different chromosomal alterations could be detected (losses on 3p, 5q, 6q, 8p, 9p, 15q, 22q, Y; gain on 7q), whereas the early-stage mesothelioma showed the same defects except for the gain on 7q. The simultaneous losses of 6q, 9p and 22q, as well as other chromosomal regions, correlate well with the most common defects previously found in 90 cases of more-advanced-stage mesotheliomas using CGH. These data demonstrate that initial chromosomal defects in early stages of mesotheliomas can be detected by conventional CGH in combination with laser microdissection. The molecular cytogenetic findings support the histological diagnosis of a pleural mesothelioma. The surprisingly high number and extent of genomic alterations found in the examined case probably reflects the genomic instability in the tumour cells and indicates a "genetic chaos" even in earlier stages of malignant mesotheliomas.

Extrapleural benign solitary fibrous tumor in the shoulder of a 9-year-old girl: case report and review of the literature

We report a case of a benign solitary fibrous tumor that occurred in the right shoulder of a 9-year-old girl. This case is remarkable due to the unusual location of its occurrence and the young age of the patient. In addition, cytogenetic analysis revealed a karyotype unreported in this neoplasm: 46,XX,der(4)t(4;9)(q31.1;q34), del(9)(p22p24),der(9)t(4;9)(q31.1;q34)ins(9;?)(q34;?) (17 cells)/46,XX (3 cells).

Solitary fibrous tumor of the pleura presenting as an aneurysm-like lesion with the strongly contrasted tumor stain by angiography

We treated a patient with solitary fibrous tumor of the pleura (SFT) whose angiograms demonstrated its feeders and strongly contrasted tumor stain. Although no one has clearly identified the specific features of SFT on angiograms, SFT can be suspected in the clinical setting if a localized chest wall tumor presents with the feeders and strongly contrasted tumor stain shown by angiography.

[Comparison of chromosomal defects in primary tumor and metastases by comparative genomic hybridization (CGH)]

Molecular methods can complement the classical methods in pathology like macroscopic, histological and immunohistochemical examinations.Comparative genomic hybridization is a cytogenetic method to screen for gains and losses of chromosomal material in tumor cells. This method allows defect studies of archival paraffin-embedded and formalin-fixed tumor material. CGH can detect gains and losses of chromosomal material that are at least 10 to 20 megabases in size. This genome-wide screening method allows to study the cytogenetic relationship between differently located tumors of a patient. To answer the question if these different tumors are metastases of the primary lung tumor or independent primary tumors CGH analysis is a supplementary method that introduces new prospectives.

[A rare case of a neuroendocrine carcinoma of the esophagus. Intermediate between a well-differentiated neuroendocrine carcinoma and a low-differentiated neuroendocrine carcinoma]

We report a rare case of a neuroendocrine carcinoma located in the esophagus of a 62-year-old male patient. The initial diagnosis of a "small-cell tumor" was based on biopsy. Our diagnosis was based on the histomorphological examination of the resected material. Diagnostic criteria were the characteristic solid or clustered growth patterns, monomorphic cell nuclei, lack of necrosis, immunohistochemical detection of neuroendocrine markers like chromogranin, synaptophysin and neuron-specific enolase (NSE) as well as detection of cytoplasmic neuroendocrine granules by electron microscopy. In addition, we found an increased prolific activity by staining with Ki67 antigen. 30% of the cell nuclei displayed a positive reaction. Focal invasion of blood vessels was also detected. With 17 different chromosomal imbalances, comparative genomic hybridization (CGH) revealed a malignant tumor stage that was not visible at the microscopic level. According to the new WHO classification of neuroendocrine tumors the described tumor was identified as an intermediate between a well-differentiated neuroendocrine carcinoma and a low-differentiated neuroendocrine carcinoma.

Video-assisted thoracoscopic surgery is a promising treatment for solitary fibrous tumor of the pleura

STUDY OBJECTIVES

Solitary fibrous tumors of the pleura (SFTPs) are slow-growing neoplasms. Approximately 800 cases have been reported in the literature to date. The aim of this study was to address our experience with the management of SFTPs and to evaluate the advantage of video-assisted thoracoscopic surgery (VATS) in SFTP treatment.

DESIGN

Retrospective analysis of our experience.

SETTING

Department of Thoracic and Cardiovascular Surgery, Nara Medical University.

PATIENTS

From January 1992 to August 2002, 13 patients with a SFTP were referred to us for surgical resection after VATS was adopted in our hospital. The study group consisted of seven men and six women with a mean age of 49.8 years (age range, 37 to 72 years).

RESULTS

Surgical excision was performed with VATS only in nine patients, with VATS plus a small thoracotomy in three patients, and by a posterolateral thoracotomy without VATS in one patient. The mean chest-drain duration was 1.3 days (range, 1 to 3 days), and the mean duration of hospital stay was 8.6 days (range, 3 to 30 days). Eleven tumors, originating from the visceral pleura, were pedunculate, and 2 tumors from the parietal pleura were not pedunculate. Two cases were focally characterized by a mitotic count in excess of four mitoses per 10 high-power fields and by cellular pleomorphism. Follow-up periods ranged from 6 to 120 months, with a mean of 49.7 months and a median of 42 months. All patients have remained well with no recurrence or metastasis.

CONCLUSIONS

Complete surgical resection is the treatment of choice for SFTPs. For the pedunculate tumors, therefore, VATS is a powerful and useful approach. Even when it is necessary to perform a small thoracotomy in addition to VATS for the removal of a large tumor, VATS may play an important role in reducing the size of the thoracotomy incision, which results in less invasive surgery. To minimize postoperative morbidity, VATS may be the most promising surgical approach for the resection of SFTPs.

Malignant solitary fibrous tumor of the pleura: report of a case with cytogenetic analysis

The majority of solitary fibrous tumors (SFTs) of the pleura are benign, but 10-30% locally recur or metastasize. Pathogenic factors relevant to the determinism of their biological properties are largely unknown. Cytogenetic data on SFTs of the pleura are sparse. We report herein a case of a malignant SFT of the pleura where successful karyotyping was obtained from the primary and recurrent tumors. The initial karyotype showed two abnormal clones: 48, XY; +8; +8; del(9)(q22; q32) [19] and 46, XY, t(1;16)(q25;p12) [7]. Culture of the recurrent tumor yielded one clone identical to the dominant clone of the initial karyotype. Demonstration of a recurrent abnormal karyotype largely supports its relevance to the malignant clone and suggests a role of supernumerary chromosome(s) 8 in the determinism of malignant behavior in SFT.

Pigmented (melanotic) neurofibroma. Report of an unusual case with immunohistochemical, ultrastructural and cytogenetic analyses

In the spectrum of neurofibromas, pigmented tumors are rare variants usually showing only faint, macroscopically obvious pigmentation. We report a case of a huge pigmented neurofibroma with extended, macroscopically striking pigmentation in a patient with stigmata of neurofibromatosis. The immunohistochemical and ultrastructural findings support a melanotic line of differentiation besides schwann cell differentiation and indicate a phenotypic neoplastic spectrum between tumorous schwann cells and melanocytes. Using comparative genomic hybridization, striking chromosomal aberrations were not detected. High level amplifications of the known chromosomal regions, including genes of major enzymes responsible for melanin synthesis, appear to be unlikely. However, smaller chromosomal defects might have been overlooked by the limited resolution of this screening method. Therefore, other mechanisms up-regulating melanogenesis, such as mutations in regulatory genes, have to be considered.

Molecular cytogenetic differences between histological subtypes of malignant mesotheliomas: DNA cytometry and comparative genomic hybridization of 90 cases

It is established that subtypes of human malignant mesotheliomas (MM) are associated with different survival times. Ninety cases of MM were examined using DNA cytometry and comparative genomic hybridization (CGH), with emphasis on the main histological subtypes; epithelioid, sarcomatoid and biphasic. A comparison by DNA cytometry revealed moderate differences, with the rare subgroup of mesodermomas having the highest and the sarcomatoid group the lowest rate of aneuploidy. Using CGH, 6.2 chromosomal imbalances per case on average could be detected. Losses (4.1/case) were more common than gains of chromosomal material (2.1/case). MM show no single, specific defect, but a typical pattern of genomic defects can be attributed to this tumour entity. Common losses are clustered at the chromosomal regions 9p21 (34%), 22q (32%), 4q31-32 (29%), 4p12-13 (25%), 14q12-24 (23%), 1p21 (21%), 13q13-14 (19%), 3p21, 6q22, 10p13-pter and 17p12-pter (16% each). Common gains are located on 8q22-23 (18%), 1q23/1q32 (16%), 7p14-15 and 15q22-25 (14% each). While differences in the frequencies of the defects between epithelioid and sarcomatoid MM are not as pronounced as are seen with the pleomorphic mesodermomas, several chromosomal locations (3p, 7q, 15q, 17p) show significant variations. The most pronounced distinguishing feature of sarcomatoid MM is a more than fourfold higher number of amplicons. These data indicate that MM has a distinctive tumour biology with a broad spectrum of heterogeneity, as reflected in morphology and also, more subtly, in the patterns of chromosomal imbalances of the subtypes.

Chromosomal imbalances in meningeal solitary fibrous tumors

We present the results of a comparative genomic hybridization (CGH) analysis of three meningeal solitary fibrous tumors (SFT). One case showed loss of chromosome 3 and two tumors had deletions of the region 3p21-p26. Other chromosomal losses included 4p15, 8q22-q24, 10, 11q14-q25, 17q11- q23, 20, and 21 in one case each. In addition, there were gains of 18p11-p13 in one case, and 1p11-p36 and 20q11-q13 in another. To our knowledge, there are no previous CGH or cytogenetic data on meningeal SFT, and loss of material on chromosome 3 has not been described in SFT at other sites. Our findings are discussed in relation to published molecular genetic and cytogenetic data on meningioma and hemangiopericytoma, the two lesions with which meningeal SFT are most likely to be confused.

Compilation of published comparative genomic hybridization studies

The power of comparative genomic hybridization (CGH) has been clearly proven since the first paper appeared in 1992 as a tool to characterize chromosomal imbalances in neoplasias. This review summarizes the chromosomal imbalances detected by CGH in solid tumors and in hemopathies. In May of 2001, we took a census of 430 articles providing information on 11,984 cases of human solid tumors or hematologic malignancies. Comparative generic hybridization has detected a number of recurrent regions of amplification or deletion that allows for identification of new chromosomal loci (oncogenes, tumor suppressor genes, or other genes) involved in the development, progression, and clonal evolution of tumors. When CGH data from different studies are combined, a pattern of nonrandom genetic aberrations appears. As expected, some of these gains and losses are common to different types of pathologies, while others are more tumor-specific.

Is 4q13 a recurring breakpoint in solitary fibrous tumors?

Solitary fibrous tumor (SFT) is a mesenchymal neoplasm found predominantly in the subpleural region but also in many other body sites. We report a malignant solitary fibrous tumor of the peritoneum with a 47,XY,t(4;9)(q13;p23),+5 karyotype. The chromosome 4q13 breakpoint in the presented and previously published case of pleural solitary fibrous tumor with a 46,XY,t(4;15)(q13;q26) karyotype was further characterized by fluorescence in situ hybridization analysis and localized within the 5-cM interval that was flanked by regions specific to YAC clones 761A7 and 886C11. Chromosome translocations involving chromosome 4q13 may characterize a separate cytogenetic subgroup of SFT.

Severe chromosomal aberrations in pleural mesotheliomas with unusual mesodermal features. Comparative genomic hybridization evidence for a mesothelioma subgroup

Malignant mesotheliomas are tumors known for their extensive heterogeneity. Apart from the three classical patterns, predominantly epithelioid, sarcomatoid, and biphasic, some rare variants do exist. In some cases, one can find uncommon additional mesodermal tumor components. These tumors have previously been called "mesodermomas" and, like regular mesotheliomas, are usually associated with a previous asbestos exposure. We examined eight cases of mesodermomas by light microscopy, immunohistochemistry and comparative genomic hybridization (CGH). Besides biphasic and epithelioid areas, unusual epithelial, chondroid, osseous, or even angioblastic elements may be found to varying degrees. Immunohistochemical analysis shows similar staining results as with regular mesotheliomas. CGH reveals a high number of chromosomal imbalances (16.5 per case; range, 11-27). In 10 classical biphasic mesotheliomas that served as a control, defects of comparable number and severity could not be detected (8 per case; range, 2-16). The most frequent defects of mesodermomas (losses on 1p, 4pq, 9p, 13q, 14q, and gains on 1q and 15q), however, could also be found in mesotheliomas of the classical type. Thus, our results support the classification of the so-called mesodermomas as a separate tumor subgroup while maintaining the relationship to the classical mesotheliomas. Therefore, we propose to use the term mesodermoma for this subgroup.