68Ga-DOTATOC PET/CT in Pleural Solitary Fibrous Tumors.

ABSTRACT: Solitary fibrous tumor of the pleura (SFTP) is a rare mesenchymal neoplasm. Preoperative diagnosis is usually difficult and based on radiological findings only. We report the imaging results observed in 5 patients with SFTP (2 malignant) obtained by 68Ga-DOTATOC PET/CT. At qualitative analysis, all tumors showed uptake of 68Ga-DOTATOC. Mean tumor SUVmax was 9.9 ± 5.7. The expression of SST2 (somatostatin receptors subtype 2) was confirmed by immunohistochemistry in 2 tumor samples, and by gene amplification of SST2 mRNA in all cases. These data suggest a diagnostic role of radioreceptor PET/CT in SFTP, and open novel potential treatment options in unresectable/metastatic disease.

[Solitary fibrous tumor of pleura (symptoms, diagnosis, treatment)]. / Solitarnaya fibroznaya opukhol' plevry (klinika, diagnostika, lechenie).

OBJECTIVE: Optimization of diagnosis and treatment of patients with solitary fibrous tumor of pleura, analysis of overall survival and disease-free survival, predictors of recurrence. MATERIAL AND METHODS: There were 66 patients with solitary fibrous tumor of pleura (26 men and 40 women) aged 57.6 years (range 26-80 years). Asymptomatic course was found in 29 (44%) patients, various symptoms - in 37 (56%) patients. Thoracotomy was applied in 36 patients, thoracoscopy - in 30 patients. Immunohistochemical examination included analysis of definition of Stat6 expression. RESULTS: Benign variant of SFT was diagnosed in 50 (75.7%) patients, malignant variant - in 16 (24.3%) patients. STAT6 expression was observed in all cases. Postoperative morbidity was 9%, mortality - 1.6%. Recurrence was diagnosed in 2 (4%) patients with benign variant of disease and in 5 (31.2%) patients with malignant variant (2 of them died from progression of disease). Progression-free survival was 89.4%, overall survival - 95.4%. Predictors of recurrence are tumor dimension over 10 cm, necrosis and/or hemorrhagic component of tumor, mitotic count of at least four per 10 high-power fields. CONCLUSION. S: Olitary fibrous tumor of pleura is a rare mesenchymal fibroblastic neoplasm growing from submesothelial layer. Differential and preoperative morphological diagnosis of SFT is difficult and demands a special immunohistochemical examination with analysis of Stat 6 expression. Surgery is preferred for tumor de novo and recurrent neoplasm.

Pleura revisited: From histology and pathophysiology to pathology and molecular biology.

Pleural cavity has an interesting physiology that when impaired gives rise to pleural effusions a rather frequent problem in respiratory medicine practice. Their aetiology varies widely producing distinct pathological lesions with different prognosis and treatment. The basic morphological features of pleural diseases, neoplastic and non-neoplastic, will be analysed in this review with an emphasis to their pathophysiology, differential diagnosis and clinicopathological correlations.

Comparison and evaluation of risk factors for meningeal, pleural, and extrapleural solitary fibrous tumors: A clinicopathological study of 92 cases confirmed by STAT6 immunohistochemical staining.

Solitary fibrous tumors (SFTs) are an uncommon type of mesenchymal tumors that are presumably fibroblastic in nature. SFTs are translocation-associated neoplasms that can be consistently diagnosed through the evaluation of NAB2/STAT6 gene fusion. Currently, SFTs have a different grading system and criteria according to their primary sites, and the differences and similarities in SFTs according to their primary sites are still poorly understood. Therefore, we compared SFTs according to their primary sites and histologic appearance, and validated the current grading system of SFTs. A total of 92 patients (with 15 meningeal, 40 pleural, and 37 extrapleural SFTs) were evaluated. The patients with pleural SFTs (mean age: 60.2 years) showed a significantly increased age at diagnosis. Tumors with hemangiopericytoma-predominant morphology had significantly higher grades in the evaluation of several risk factors such as cellularity (P<0.001), pleomorphism (P=0.001), and mitotic activity (P<0.001). Consequently, hemangiopericytoma (HPC)-predominant tumors had a significantly higher recurrence rate. The meningeal SFT group had significantly higher proportion of the HPC-predominant histologic phenotype compared with pleural or extrapleural SFTs (66.67% vs. 5.00% or 18.92%, respectively; P<0.001). Consequently, meningeal SFTs showed significantly higher recurrence rates compared with pleural or extrapleural SFTs (33.33% vs. 12.50% or 2.70%, respectively; P=0.009). Regarding the evaluation of risk factors, a tumor size ≥10cm (P=0.017), a mitotic index ≥4/10 high power fields (HPFs) (P=0.001), high tumor cellularity (P=0.003), high nuclear pleomorphism (P=0.005), and tumor necrosis (P=0.004) were associated with both recurrence and disease-specific mortality. Upon evaluation of the usefulness of the criteria using previously described factors, the predictive model was on the borderline of validation. Of the five factors indicated in the log rank test, only a mitotic index ≥4/10 HPFs remained a significant factor in the multivariate Cox model.

68Ga-DOTATOC PET/CT Imaging in Solitary Fibrous Tumor of the Pleura.

Here we describe a 77-year-old man with a solitary fibrous tumor of the pleura showing increasing tracer uptake at Ga-DOTATOC PET/CT, demonstrating that solitary fibrous tumor of the pleura may overexpress somatostatin receptors, therefore mimicking neuroendocrine tumors at somatostatin receptor PET/CT.

Low tissue levels of miR-125b predict malignancy in solitary fibrous tumors of the pleura.

BACKGROUND: Solitary fibrous tumors of the pleura (SFTP) are rare neoplasia of the chest. A subset of SFTP follows a malignant course, sometimes several years after complete resection. Traditional scoring systems based on clinical and histological features are poor predictors of biological behavior. This study aimed to investigate tumor-associated miRNAs expression as novel biomarkers to predict the clinical behavior of SFTP. METHODS: Formalin-fixed and paraffin-embedded SFTP tissues blocks from patients surgically resected between 1992 and 2013 at two tertiary care teaching hospitals were included. SFTP tumors were categorized as either malignant or benign variants according to the WHO classification. Following miRNAs levels were measured: let-7a, miR-16b, miR-17, miR-21, miR-31, miR-34a, miR-92a, miR-125a, miR-125b, miR-195-5b, miR-203a, and miR-223. Differential gene expressions which were calculated with the threshold cycle (Ct) method were compared among the two variants. RESULTS: Thirty-eight patients (40% male, mean age 62.2 (±10.9) years) were included. Expression levels of miR-125b showed a significant difference between benign compared to malignant variants (-3.08 ± 0.93 vs. -2.22 ± 1.36, p = 0.0068). Furthermore, lower levels of miR-125b were found to be associated with increased tumor size (p = 0.0414). Thus, downregulation of miR-125b indicates malignant transformation. All other investigated miRNAs were not associated with grading of SFTP. CONCLUSIONS: Our data suggest a potential role of miR-125b in the pathogenesis of tumor growth and malignant transformation of SFTP, respectively. Further studies have to address the potential use of miRNA-125b as a biomarker or therapeutic target in SFTP.

Tumor fibroso pleural gigante / Giant pleural fibrous tumour

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Chemotherapy management of malignant pleural mesothelioma: a phase II study comparing two popular chemotherapy regimens

PURPOSE: The aim of this prospective, phase II clinical study is to evaluate the activity of gemcitabine and cisplatin in comparison to pemetrexed and carboplatin in patients with malignant pleural mesothelioma. PATIENTS AND METHODS: The patients were recruited from May 2008 to May 2011. One group included 21 cases who received cisplatin and gemcitabine. The other group included 19 cases who received pemetrexed and carboplatin. RESULTS: Response is superior in the pemetrexed group (p = 0.041). The median follow-up was 18 months (range 6-30 months). Cumulative survival at 1.5 years was 57.8 % for the pemetrexed carboplatin group. For the gemcitabine cisplatin group, the cumulative survival proportion at 1.5 years was 41 % (p = 0.0599). CONCLUSIONS: Pemetrexed plus carboplatin are a step forward in the treatment of mesothelioma, the prognosis for these patients remains poor. Cheaper combinations as gemcitabine and cisplatin may be considered sufficient to treat cases with advanced mesothelioma (AU)

Giant fibrous tumours of the pleura with mucus secretion.

Solitary fibrous tumors of the pleura (SFTP) are rare. We report a case of giant SFTP treated by surgical resection. We found that many soft tumors were separated by fibrous cords and creamy white mucus in our case. Among them, one great mass measured 23 cm × 18 cm × 10 cm. These tumors weighed 3750 g. The patient had no postoperative complications and received a good prognosis.

Recurrent solitary fibrous tumor of the pleura with malignant transformation and non-islet cell tumor-induced hypoglycemia due to paraneoplastic overexpression and secretion of high-molecular-weight insulin-like growth factor II.

A 41-year-old man was diagnosed with a solitary fibrous tumor (SFT) of the pleura in the posterior mediastinum. Despite two surgeries for excision, the SFT recurred and progressed with direct invasion of the chest wall and bone metastases. He was hospitalized because of cerebral infarction and presented with recurrent severe hypoglycemia fourteen years later. High-molecular-weight (HMW) insulin-like growth factor II (IGF-II) was identified in the serum and tumor using Western blotting and immunohistochemistry. These findings suggested that the cause of the recurrent severe hypoglycemia was SFT production of HMW IGF-II, a mediator of non-islet cell tumor-induced hypoglycemia (NICTH).

A rare case of hypoglycemia in a patient with elevated right hemidiaphragm.

A 57-year-old woman was admitted to the emergency department, presenting with episodes of altered consciousness and behaviour which, upon further examination, were linked to periods of recurrent hypoglycaemia. Imaging revealed a large mass in the right thoracic cavity while blood analysis demonstrated diminished C-peptide, (pro-)insulin, insulin-like growth factor 1 (IGF-I) and IGF binding protein 3 levels. Based on these findings, an IGF-II secreting tumour was suspected. Before the excision of the tumour, euglycaemia could only be achieved by means of intravenous glucose administration and the use of oral corticosteroids. Anatomopathologically the diagnosis of a solitary fibrous tumour (SFT) was confirmed. Immunoblot analysis on the serum revealed elevated 'big'-IGF-II levels, confirming our initial diagnosis of Doege-Potter syndrome in SFT.

Expression of CD44 and MMP-2: possible association with histopathological features of pleuro-pulmonary solitary fibrous tumors.

OBJECTIVE: Recent studies have shown that tumor cell adhesion molecules CD44 and matrix metalloproteinases (MMP-2) are expressed strongly in many tumors and associated closely with invasion and metastasis of these tumors. Although solitary fibrous tumors (SFT) have a good prognosis, a minority behave malignantly. The aim of this study was to analyze the correlation between CD44 and MMP-2 expression with histopathological parameters in SFT. MATERIAL AND METHOD: Haemotaxylin-Eosin stained sections of 10 patients with SFT were reexamined for evaluation of histopathological parameters. Immunostaining of CD44 and MMP-2 was performed by using the streptavidin-biotin method with mouse monoclonal antibody. RESULTS: Our cases consisted of three male and seven female patients with a mean age of 54.5 years. Three patients had a history of asbest exposure. Complete resection was performed in 2 malignant (multiple masses) and 8 benign SFT cases. One intrapulmonary tumor was treated with pneumonectomy. 3 cases originated from the right and 7 from the left hemithorax. Tumor size ranged from 5 to 27cm. All cases expressed strong CD44. Only 2 malignant SFT and intrapulmonary SFT expressed focal MMP-2. CONCLUSION: Although MMP-2 positivity was observed in 2 malignant cases, CD44 positivity was not associated with malignancy criteria in solitary fibrous tumors.

Localized malignant lymphohistiocytoid pleural mesothelioma.

We report a case of a 42-year-old man with a right pleural mesothelioma. This neoplasm has 3 rare features. Firstly, it was a localized form: suspected by imaging, visualized by video-assisted thoracoscopy, at the time of the curative-thoracotomy and confirmed by the pathological analysis. The second characteristic is its histological type: "malignant lymphohistiocytoid mesothelioma". This rare subtype has been reported in only 4 papers. Third, after pleuro-pneumonectomy, our patient is alive after 6 years and 5 months postoperatively without any sign of recurrence. Only one case with a long follow-up has been reported but with recurrence at 5 years postoperatively.

Large solitary fibrous tumor with overexpression of insulin-like growth factor-2.

We present the case of a 66-year-old woman in whom a large solitary fibrous tumor (SFT) in the right thoracic cavity caused intermittent symptoms of hypoglycemia. A diagnosis was made of non-islet cell tumor hypoglycemia on the basis of the presence of hypoglycemia requiring continuous glucose infusion, elevated serum insulin-like growth factor-2 (IGF-2), and a large well-defined tumor in the right thoracic cavity. The patient underwent complete resection of the tumor. Histological examination revealed spindle tumor cells with a hemangiopericytoma-like vascular pattern. Mitotic figures and necrotic areas were rare, and cellular atypia and nuclear pleomorphism were mild. Under immunohistochemical examination, the tumor cells were positive for CD34. Overexpression of IGF-2 mRNA in the tumor was detected by reverse-transcription polymerase-chain reaction. The diagnosis of SFT with IGF-2 production was confirmed. Immediately after surgery, her serum glucose level was normalized (without the need for glucose infusion) and serum IGF-2 level was decreased. Two years after surgery, the patient remains alive and well, with no signs of recurrence or hypoglycemia.

[Imaging features and clinicopathological manifestations of solitary fibrous tumors].

OBJECTIVE: To investigate the imaging features, clinical manifestations and pathological characteristics of solitary fibrous tumors (SFT). METHODS: The clinicopathological manifestations and medical imaging findings were analyzed retrospectively in 27 patients with surgically confirmed SFT. RESULTS: The SFTs originated from different parts of the body, including 18 in the chest, 4 in the abdomen, 1 in the lumboscral area, 3 in the pelvis, and 1 in the left shoulder. Twenty-three cases were found by CT scan, among which there were 16 benign diseases, presented with well-defined round or elliptic margins, with homogeneous attenuation and clearly surrounding; 6 malignant cases with unclear demarcations, invasive surrounding, heterogeneous attenuation due to calcification and/or irregular necrosis, and 1 junctional case with well-defined margins, which was enlarged during follow-up. There were 4 SFTs scanned by MRI with clear margin and homogeneous or heterogeneous signal intensity. All of the 4 cases were isointense or hyperintense to muscle on T1-weighted images, and were hyperintense on the T2-weighted images. All tumors showed heterogeneously intense enhancement with geographic pattern. Immunohistochemical staining showed that CD34-positive was 81.5%, vimentin (100.0%), CD99 (100.0%) and bcl-2 (96.3%), as well as negative CK (100.0%) and S-100 (96.3%). CONCLUSION: The location of SFT is varying. Though its clinical manifestations vary, the diagnosis is depended on pathology and immunohistochemistry. There are certain specific features related to SFTs on CT or MRI. These imaging techniques may serve to provide helpful information as to the location and vicinal anatomic structure of the tumor, which is of substantial importance for planning surgery.

Is D2-40 a useful marker for distinguishing malignant mesothelioma from pulmonary adenocarcinoma and benign mesothelial proliferations?

Since pulmonary adenocarcinomas, malignant mesotheliomas (MM), and sometimes benign mesothelial proliferations show a great histomorphological resemblance to each other, an immunohistochemical panel is usually necessary for differential diagnosis. D2-40 is an available monoclonal antibody, which is already in use as a lymphatic endothelial marker. It has also been suggested to be useful in identifying the mesothelial differentiation. The aim of this study is to compare D2-40 immunostaining in MM, pulmonary adenocarcinoma, and benign mesothelial proliferations. In this retrospective study, D2-40 immunostaining was investigated in 37 cases of MM, 36 cases of pulmonary adenocarcinoma, and 31 cases of benign mesothelial proliferation. The diagnosis of MM had previously been confirmed by a panel including calretinin, CK5/6, and CEA. Predominantly membranous immunoreactivity was observed in 51% of MMs and in 55% of benign mesothelial proliferations. All the 36 pulmonary adenocarcinomas were negative. These results were statistically significant (p<0.001). We believe that D2-40 may be helpful in the differential diagnosis of MM from pleural involvement of pulmonary adenocarcinoma.

Solitary fibrous tumors of the pleura presenting satellite tumors.

A 29-year-old man presented with a mass in the left lower lung field on a chest radiograph obtained during a medical checkup. Computed tomography revealed a tumor adjacent to the diaphragm. A sessile tumor measuring 10.5 x 8.5 x 4.5 cm arising from the parietal pleura was resected. The tumor was accompanied by several little tumors on the nearby diaphragm. Pathologically, the major tumor consisted of typical spindle-shaped cells with myxoid degeneration. There was no increased cellularity, cellular pleomorphism, or a high mitotic count. In immunohistochemical studies, the spindle cells showed positive staining for CD34 and were negative for bcl-2. The smaller tumors also consisted of myxoid degeneration. We diagnosed benign solitary fibrous tumor of the pleura with satellite tumors. We must be aware of the possibility of satellite tumors when we treat patients with a benign solitary fibrous tumor.

[Clinicopathologic characteristics of hemangiopericytoma/solitary fibrous tumor with giant cells].

OBJECTIVE: To study the pathological characteristics, diagnosis and differential diagnoses of hemangiopericytoma-solitary fibrous tumor with giant cells. METHODS: Pathological characteristics of seven cases of orbital and extraorbital hemangiopericytoma-solitary fibrous tumors with giant cells were evaluated by HE and immunohistochemistry (EnVision method). RESULTS: Two cases were located in the orbit, one of which had recurred. Five cases were located in the extraorbital regions. Histologically, the tumors were well-circumscribed and composed of non-atypical, round to spindle cells with collagen deposition in the stroma. The tumors had prominent vasculatures and in areas, pseudovascular spaces lined by multinucleated giant cells lining which were also present in the stroma. Immunohistochemically, both neoplastic cells and multinucleate giant cells expressed CD34. Seven patients underwent tumor excision and were well and without tumor recurrence upon the clinical follow-up. CONCLUSIONS: Hemangiopericytoma-solitary fibrous tumor with giant cells is an intermediate soft tissue tumor. It typically involves the orbital or extraorbital regions. Histologically, the tumor should be distinguished from giant cell fibroblastoma, pleomorphic hyalinzing angiectatic tumor of soft part and angiomatoid fibrous histiocytoma.

Tumorigenic properties of alternative osteopontin isoforms in mesothelioma.

Osteopontin (SPP1) is an inflammatory cytokine that we previously characterized as a diagnostic marker in patients with asbestos-induced malignant mesothelioma (MM). While SPP1 shows both pro- and anti-tumorigenic biological effects, little is known about the molecular basis of these activities. In this study, we demonstrate that while healthy pleura possesses all three differentially spliced SPP1 isoforms (A-C), in clinical MM specimens isoform A is markedly up-regulated and predominant. To provide a clue to possible functions of the SPP1 isoforms we next performed their functional evaluation via transient expression in MM cell lines. As a result, we report that isoforms A-C demonstrate different activities in cell proliferation, wound closure, and invasion assays. These findings suggest different functions for SPP1 isoforms and underline pro-tumorigenic properties of isoforms A and B.