Malignant Pleural Lesions Research Articles

Contrast-enhanced ultrasound is helpful for differentiating benign from malignant parietal pleural lesions.

To describe the value of contrast-enhanced ultrasound (CEUS) for the differentiation of malignant from benign parietal pleural lesions (PPLs). From November 2005 to June 2019, 63 patients with histologically/cytologically confirmed PPLs were investigated by CEUS. On CEUS, the extent of enhancement (EE; marked or reduced/absent) and the homogeneity of enhancement (HE; homogeneous or inhomogeneous) were analyzed retrospectively. In total, 24/63 lesions were benign, and 39/63 lesions were malignant. On CEUS, 11/24 benign and 36/39 malignant lesions showed a marked enhancement. A marked enhancement was significantly more frequently associated with malignancy compared with benign lesions (p< 0.001). In five cases, due to the absence of enhancement, it was not possible to determine the HE. In the remaining cases, 9/20 benign and 19/38 malignant lesions showed an inhomogeneous enhancement (p = 0.79). On CEUS, marked enhancement was significantly more frequently associated with malignant compared with benign lesions. However, some benign lesions, such as chronic inflammatory processes, may also show a marked enhancement. Therefore, the interpretation of perfusion patterns in these lesions must always take into account the clinical background of the patient.

The role of 18F-FDG-PET/CT in the evaluation of malignant mesothelioma

Background Fluorodeoxyglucose–positron emission tomography/computed tomography (FDG–PET/CT) play an important role in the diagnostic workup of patients with malignant mesothelioma. Applications for FDG–PET/CT at this time help in differentiation between malignant and benign pleural lesions, staging, and the ability for surgical interference. Objectives The objective of this study was to review the role of PET/CT in diagnosis, staging, prognostication, and pre- and post-therapeutic response of malignant mesothelioma. Patients and methods This study was performed on 55 of known patients with malignant mesothelioma at Naser Institute (cancer center) from May 2016 to July 2020 referred for staging, pre-, and post-therapeutic response. Results The study proved that combined PET/CT was superior to CT and PET individually in diagnosis of patients with malignant mesothelioma and improves the sensitivity, specificity, and accuracy of local extent (T), regional lymph nodes (N), and distant metastases (M), also pre- and post-therapeutic response. Conclusion The information provided by PET/CT is likely to obtain the best imaging for the diagnosis and staging in patients with malignant mesothelioma and also for monitoring tumor response to therapy.

Evaluation of pleural lesions after pleurodesis with OK-432 by fluorodeoxyglucose-positron emission tomography/CT.

This study aimed to determine changes in FDG-PET/CT after pleurodesis with OK-432 and to investigate differences in the changes between non-malignant and malignant lesions. Study participants were 17 patients with a history of malignant chest disease who underwent FDG-PET/CT after pleurodesis using OK-432 and in whom pleural lesions were determined to be non-malignant (n = 8) or malignant (n = 9). FDG uptake (SUVmax) was counted on all pleural lesions. CT findings (CT attenuation, shape) of pleural lesions with increased FDG uptake were evaluated. The number of patients with increased FDG uptake in the pleura differed significantly between the non-malignant group (3/8) and malignant group (9/9) (p < 0.01) The mean SUVmax of non-malignant lesions with increased FDG uptake was 2.3 ± 0.7 vs. 6.2 ± 2.2 in malignant lesions, for a significant difference (p < 0.01). The mean CT attenuation of lesions was 36 ± 11 HU in the non-malignant group and 34 ± 14 HU in the malignant group, a difference that was not significant (p = 0.91). There was a significant difference in nodular and linear shapes between non-malignant and malignant lesions (p < 0.01). All non-malignant lesions were linear. Positive FDG uptake was shown in non-malignant pleural lesions as well as in malignant pleural lesions after pleurodesis using OK-432. Combined analysis of FDG accumulation and CT morphology is helpful to distinguish between benign and malignant lesions.

Photodynamic Diagnosis for Pleural Disseminated Lesions of Lung Cancer Using a Combination of 5-Aminolevulinic Acid and Autofluorescence Observation System.

We developed a diagnostic method for pleural disseminated lesions of lung cancer using a combination of 5-aminolevulinic acid (5ALA) and autofluorescence observation system. We utilized a phenomenon in which externally ingested 5ALA is metabolized to protoporphyrin IX, a precursor of heme, which remains inside malignant cells and emits red fluorescence of approximately 630 nm. The diagnosis was made employing an observation system based on autofluorescence emitted from normal tissues that we have investigated. Between January 2017 and April 2019, we examined 82 lung cancer patients with suspected pleural invasion. We orally administered 5ALA (20 mg/m2) to the patients 4 hours before surgery, and malignant pleural lesions were thoracoscopically visualized using the autofluorescence observation system. (1) Pleural disseminated lesions were observed in six patients. Of these lesions, two were not detected by usual white light inspection, and the use of this method enabled the diagnosis of disseminated lesions. (2) Regarding the diagnosis of lung cancer pleural invasion to estimate the risk of pleural dissemination, if limited to adenocarcinoma, the sensitivity was 93.9%; specificity, 74.3%; positive predictive value, 60.8%; and negative predictive value, 96.2%. This method may facilitate the detection of minute disseminated lesions that are difficult to detect by usual inspection. In addition, the degree of pleural invasion may be diagnosed to evaluate the need for limited resection such as segmentectomy.

Is transthoracic ultrasound (TUS) a reliable predictor of the nature of pleural and peripheral pulmonary lesions? Correlation with cyto-histological findings

BackgroundWe focused on determining the most reliable transthoracic ultrasound (TUS) criteria that can predict malignancy of the pleural and peripheral pulmonary lesions and correlating our data with CT and cyto-histological findings. Sixty-nine patients (38 males and 31 females) were enrolled in our prospective study. They were divided into group I (48 patients), which included patients with pleural effusion, and group II (21 patients), which included patients with peripheral pulmonary lesions. All patients underwent chest X-ray (postero-anterior and lateral views), transthoracic ultrasound (TUS), CT chest, guided Tru-cut or surgical biopsies and histopathology, and/or needle aspiration and cytology.ResultsIn group I, the presence of pleural nodularity was a predictor of malignancy with significant statistical difference (b value < 0.001) and receiver operating curve (ROC) curve analysis showed pleural thickening cutoff value of 7 mm at a maximum combined sensitivity and specificity of 75% and 80% respectively and area under the curve 0.825. In group II, distorted intralesional vascular pattern, pleural, and chest wall invasion were statistically significant ultrasonographic malignant predictors (b values are <0.001, 0.016, and 0.004 respectively).ConclusionTUS is a valuable and safe complementary method in differentiation between benign and malignant pleural effusion and peripheral pulmonary lesions but is not a substitute for CT.

Computed tomography and magnetic resonance imaging in diagnosis of metastatic pleural lesion with pleural effusion in patients with breast carcinoma

An uncommon case of metastatic pleural lesion with pleural effusion in a patient with phyllodes breast tumor is reported in this article. This clinical case demonstrates that computed tomography and magnetic resonance imaging (MRI) with dynamic contrast enhancement is a highly valuable methods to diagnose malignant pleural lesions and to differentiate soft-tissue mass from fluid. MRI was the most useful as it allowed visualization tumor macrostructure and volume, and differentiation soft tissue from fluid, both visually and with diffusion weighted images.

Molecular markers and new diagnostic methods to differentiate malignant from benign mesothelial pleural proliferations: a literature review.

Malignant pleural mesothelioma (MPM) is an aggressive tumor associated with asbestos exposure. Histopathological analysis of pleural tissues is the gold standard for diagnosis; however, it can be difficult to differentiate malignant from benign pleural lesions. The purpose of this review is to describe the most important biomarkers and new diagnostic tools suggested for this differential diagnosis. There are many studies concerning the separation between MPM and benign pleural proliferations from both pleural tissues or effusions; most of them are based on the evaluation of one or few biomarkers by immunohistochemistry (IHC) or enzyme-linked immunosorbent assays (ELISAs), whereas others focused on the identification of MPM signatures given by microRNA (miRNA) or gene expression profiles as well as on the combination of molecular data and classification algorithms. None of the reported biomarkers showed adequate diagnostic accuracy, except for p16 [evaluated by fluorescent in situ hybridization (FISH)] and BAP1 (evaluated by IHC), both biomarkers are recommended by the International Mesothelioma Interest Group guidelines for histological and cytological diagnosis. BAP1 and p16 showed a specificity of 100% in discerning malignant from benign lesions because they are exclusively unexpressed or deleted in MPM. However, their sensitivity, even when used together, is not completely sufficient, and absence of their alterations cannot confirm the benign nature of the lesion. Recently, the availability of new techniques and increasing knowledge regarding MPM genetics led to the definition of some molecular panels, including genes or miRNAs specifically deregulated in MPM, that are extremely valuable for differential diagnosis. Moreover, the development of classification algorithms is facilitating the application of molecular data for clinical practice. Data regarding new diagnostic tools and MPM signatures are absolutely promising; however, before their application in clinical practice, a prospective validation is necessary, as these approaches could surely improve the differential diagnosis between malignant and benign pleural lesions.

Can CT and MR Shape and Textural Features Differentiate Benign Versus Malignant Pleural Lesions?

The study aimed to identify a radiomic approach based on CT and or magnetic resonance (MR) features (shape and texture) that may help differentiate benign versus malignant pleural lesions, and to assess if the radiomic model may improve confidence and accuracy of radiologists with different subspecialty backgrounds. Twenty-nine patients with pleural lesions studied on both contrast-enhanced CT and MR imaging were reviewed retrospectively. Three texture and three shape features were extracted. Combinations of features were used to generate logistic regression models using histopathology as outcome. Two thoracic and two abdominal radiologists evaluated their degree of confidence in malignancy. Diagnostic accuracy of radiologists was determined using contingency tables. Cohen's kappa coefficient was used to assess inter-reader agreement. Using optimal threshold criteria, sensitivity, specificity, and accuracy of each feature and combination of features were obtained and compared to the accuracy and confidence of radiologists. The CT model that best discriminated malignant from benign lesions revealed an AUCCT = 0.92 ± 0.05 (P < 0.0001). The most discriminative MR model showed an AUCMR = 0.87 ± 0.09 (P < 0.0001). The CT model was compared to the diagnostic confidence of all radiologists and the model outperformed both abdominal radiologists (P < 0.002), whereas the top discriminative MR model outperformed one of the abdominal radiologists (P = 0.02). The most discriminative MR model was more accurate than one abdominal (P = 0.04) and one thoracic radiologist (P = 0.02). Quantitative textural and shape analysis may help distinguish malignant from benign lesions. A radiomics-based approach may increase diagnostic confidence of abdominal radiologists on CT and MR and may potentially improve radiologists' accuracy in the assessment of pleural lesions characterized by MR.

Malignant pleural effusion: Relationship between thoracoscopic findings and type of malignancy

BackgroundPleural malignancy either primary or due to metastatic involvement can be presented by different macroscopic appearances in thoracoscopic examination of pleural cavity. PurposeTo identify the relationship between thoracoscopic view of different malignant pleural lesions and pathological types of malignancy in malignant pleural effusion. Patients and methodsA retrospective study reviewing medical reports of sixty-nine (69) patients who underwent medical thoracoscopy and were confirmed to be malignant pleural effusion by pleural tissue biopsy as well as macroscopic appearances of malignant pleural lesions were identified. ResultsMetastatic adenocarcinoma was the main type of malignancy (46 cases 66.7%), followed by malignant lymphoma (9 cases 13%), malignant mesothelioma (4 cases 5.8%), squamous cell carcinoma (4 cases 5.8%), small cell carcinoma (3 cases 4.3%), sarcoma (2 cases 2.9%) and lastly spindle cell tumor (single case 1.4%). Nodular appearance of malignant pleural lesions was the main thoracoscopic finding (75.45%) followed by masses (50.7%), plaques (20.3%) and lastly adhesions (14.5%) of cases. Nodules represented the main thoracoscopic finding in both metastatic adenocarcinoma and malignant lymphoma (82.6% and 77.78%, respectively) afterward masses (45.65% and 66.67%, respectively). However; masses represented the main thoracoscopic finding (100%) in malignant mesothelioma followed by nodules (50%). ConclusionInspecting pleural cavity via medical thoracoscopy and identification of macroscopic appearance of different malignant pleural lesions may give a good prospect about the suspected pathological type of malignancy in malignant pleural effusion.

Correlation between computed tomography of the chest and medical thoracoscopic findings in primary pleural tumors

Malignant pleural mesothelioma ( MPM) is an aggressive tumor arising from the mesothelial cells lining the pleura. It commonly presents with unilateral pleural effusion with variable degree of pleural thickening and nodularity. MPM usually develops on the parietal pleura, and involvement of the visceral pleura indicates more advanced stage. Treatment of MPM should not be started before correct diagnosis and staging with computed tomography (CT) and thoracoscopy. The aim of this study was to assess the correlation between findings on chest CT and those on thoracoscopy and to evaluate the sensitivity of chest CT to identify malignant pleural lesions. Patients with suspected MPM and indicated for medical thoracoscopy for diagnostic confirmation were enrolled in the present study. Twenty patients with confirmed diagnosis after tissue biopsies with medical thoracoscopy were selected. Comparison and correlation between CT findings and medical thoracoscopic findings were made. Thoracoscopy showed parietal pleural invasion in all patients, whereas noncontrast chest CT showed parietal pleural lesions in 14 patients (70%). Visceral pleural involvement was evident in 13 patients (65%) on thoracoscopy, but chest CT detected only one case (5%) with visceral pleural involvement. Three patients (15%) were found to have fibrous septations on thoracoscopy, compared with only one patient (5%) on chest CT. The sensitivity of noncontrast chest CT in the detection of MPM was 70%. Although the sensitivity of noncontrast chest CT in the detection of MPM is high, thoracoscopy is needed not only to confirm the diagnosis but also to assess the different parts of the pleura and to allow proper staging of the disease. Egypt J Broncho 2014 8:32–37

Pleural Changes after Talc Pleurodesis in Patients with Underlying Malignancy: Comparison with Recurrent Malignant Pleural Lesions on CT and Fluorodeoxyglucose-Positron Emission Tomography/CT

Pleural Changes after Talc Pleurodesis in Patients with Underlying Malignancy: Comparison with Recurrent Malignant Pleural Lesions on CT and Fluorodeoxyglucose-Positron Emission Tomography/CT

Value of Autofluorescence in Video-Assisted Thoracoscopic Surgery in Pleural Diseases

Autofluorescence (AF) examination in thoracoscopy has not been used frequently. Here, our aim was to determine whether AF examination contributes additional information to white-light (WL) examination when attempting to detect malignant pleural lesions. We also liked to know whether the effectiveness of WL and AF-mode combination would be different for various pathologies or lesions of the pleura. It is a retrospective study. Thirty-three patients with unexplained exudative pleural effusions underwent AF-assisted video-assisted thoracic surgery (VATS). Patients' data from the files were evaluated. In each case, the pleural cavity was thoroughly examined under WL alone and then in AF mode. The sensitivity and specificity of AF-assisted VATS for detecting malignant pleural lesions were 78.7 and 85%, respectively, and there were 21.3% false negatives. In the group with metastatic pleural disease, AF VATS correctly identified all lesions as AF positive, whereas sensitivity was lower for the group with malignant mesothelioma. Seven lesions, which were not diagnosed under WL, were detected in AF mode. The overall sensitivity of AF-assisted VATS for detecting pleural malignancies was not satisfactory because of diagnostic errors in malignant mesothelioma. But it would be useful in detecting small malignant pleural lesions, which are not diagnosed under WL.

Echopulmonography versus computed tomographic chest predictors for differentiation between benign and malignant peripheral pulmonary and pleural lesions

BackgroundDiagnostic value of echopulmonography (EPG) in chest diseases is expanding as a guide to discriminate between benign and malignant parenchymal lesions as regards tissue characterization plus pleural lesions’ diagnostic specification. ObjectivesTo determine echopulmonography predictors of malignancy in patients with peripheral pulmonary and solid pleural lesions. Patients and methodsA prospective clinical study was conducted on 122 patients who presented with peripheral pulmonary and pleural lesions by chest X-ray. They underwent echopulmonography and CT chest evaluation. Patients were divided into two groups: Group (1), 63 patients diagnosed by CT chest and CT guided biopsy followed by EPG. Group (2), 59 patients diagnosed by EPG and ultrasound (US) guided biopsy followed by CT chest. Tissue biopsy was taken either through CT guided biopsy or ultrasound guided biopsy for pathological examination. ResultsEPG had a success rate of 75.9% in diagnosing malignancy and 17.2% in diagnosing nonmalignant lesions. Success rate of EPG based diagnosis in all studied cases was 45%. Using EPG criteria; rounded and oval morphology was statistically significantly higher in malignant than nonmalignant subgroups (53.4% versus 32.8%) in contrast to irregular morphology with ramifications that prevailed in the nonmalignant subgroup (67.2% versus 46.5%). Irregular pleural contour and heterogeneous hypoechogenicity were predominant in the nonmalignant subgroup (67.1% and 28.1%, respectively). Echoinvasion, destruction of normal tissue architecture and blood vessels displacement were more common in malignant than nonmalignant subgroups. ConclusionEchopulmonography has a worthy role in differentiating benign from malignant peripheral pulmonary and pleural lesions. US guided biopsy is performed with a low risk of complications.

The role of FDG PET-CT in differential diagnosis of pleural pathologies

ObjectiveThis study has aimed to evaluate the impact of F18 Fluorodeoxyglucose Positron Emission Tomography-Computed Tomography (FDG PET-CT) in the differential diagnosis of malignant and benign pleural lesions in patients with suspected malignant pleural mesothelioma (MPM). Material and methodsFifty patients (32 females, 18 males; age range 24–79 years) with pleural thickening, fluid, plaques or calcification on previous CT scan were examined with FDG PET-CT. PET-CT imaging was obtained 1h after FDG injection. In 12 patients, delayed imaging from the thoracic region was performed 2h after injection. FDG uptake was evaluated visually and semiquantitively using standardized uptake value (SUV). FDG PET-CT findings were compared with histopathologic diagnosis. ResultsThirty-nine patients had increased FDG uptake in pleural lesions but PET-CT results were negative in 11 patients. When compared with histopathological results in FDG positive group, 34 patients had MPM, 5 had benign pathology; in FDG negative group 8 patients had benign pathology, 3 had MPM. Of patients with delayed imaging, 9 showed increased SUV but 3 had a decreased SUV on delayed images. Increased SUV group had 4 MPM, 5 benign pathology (3 chronic granulomatous inflammation, 2 benign asbestotic plaque). Decreased SUV group all had benign pathology (fibrosis, chronic inflammation, myofibrosis). DiscussionFDG PET-CT is a useful imaging modality in differential diagnosis of malignant and benign pleural lesions. Delayed imaging seems to be useful if there is a decrease in SUV suggesting a benign pathology but does not seem to contribute to the differential diagnosis if the SUV is increased.

The role of FDG PET-CT in differential diagnosis of pleural pathologies

ObjectiveThis study has aimed to evaluate the impact of F18 Fluorodeoxyglucose Positron Emission Tomography-Computed Tomography (FDG PET-CT) in the differential diagnosis of malignant and benign pleural lesions in patients with suspected malignant pleural mesothelioma (MPM). Material and methodsFifty patients (32 females, 18 males; age range 24–79 years) with pleural thickening, fluid, plaques or calcification on previous CT scan were examined with FDG PET-CT. PET-CT imaging was obtained 1h after FDG injection. In 12 patients, delayed imaging from the thoracic region was performed 2h after injection. FDG uptake was evaluated visually and semiquantitively using standardized uptake value (SUV). FDG PET-CT findings were compared with histopathologic diagnosis. ResultsThirty-nine patients had increased FDG uptake in pleural lesions but PET-CT results were negative in 11 patients. When compared with histopathological results in FDG positive group, 34 patients had MPM, 5 had benign pathology; in FDG negative group 8 patients had benign pathology, 3 had MPM. Of patients with delayed imaging, 9 showed increased SUV but 3 had a decreased SUV on delayed images. Increased SUV group had 4 MPM, 5 benign pathology (3 chronic granulomatous inflammation, 2 benign asbestotic plaque). Decreased SUV group all had benign pathology (fibrosis, chronic inflammation, myofibrosis). DiscussionFDG PET-CT is a useful imaging modality in differential diagnosis of malignant and benign pleural lesions. Delayed imaging seems to be useful if there is a decrease in SUV suggesting a benign pathology but does not seem to contribute to the differential diagnosis if the SUV is increased.

Adenomatoid tumor of the pleura

A case of adenomatoid tumor of the pleura is reported, and its differential diagnosis from benign and malignant pleural lesions is discussed. A small pleural nodule was incidentally found during a thoracic operation in a 54-year-old woman with esophageal cancer. The patient had no history of exposure to asbestos, and was well with no sign of recurrence 14 months after the operation. A 7 mm, circumscribed tumor had characteristic features of adenomatoid tumor. The tumor was composed of an aggregation of irregularly shaped tubulocystic spaces with fibrous stoma. The spaces were lined by flattened and occasional cuboidal epithelioid cells with cytoplasmic vacuolization, and several spaces contained pale blue mucinous fluid. On immunohistochemistry the tumor cells were positive for AE1/AE3, CAM5.2, vimentin, cytokeratin 5/6, D2-40, calretinin, thrombomodulin, and WT-1, but negative for CEA, Leu M1 (CD15), thyroid transcription factor-1, epithelial membrane antigen, desmin, glucose transporter-1 (GLUT-1), CD31, and CD34. The MIB-1 (Ki-67) labeling index was 1-2%, indicating low proliferative activity. Adenomatoid tumor of the pleura is rare, and the pathogenesis has not been elucidated. Recognition of these benign mesothelial lesions in the pleura is important to avoid misdiagnosis. The immunohistochemistry in the present case supports its mesothelial origin.

Potential of Dual Time Point FDG-PET Imaging in Differentiating Malignant from Benign Pleural Disease

The aim of this study was to assess the utility of dual time point 18F-fluorodeoxyglucose positron emission tomography (18F-FDG-PET) imaging in differentiating benign from malignant pleural disease. Fifty-five consecutive patients of suspected malignant pleural mesothelioma (MPM) and recurrence of MPM who were referred for the evaluation underwent two sequential 18F-FDG-PET scans (dual time point imaging). The average percent change in the maximum standardized uptake values (Delta%SUVmax) of the lesion/lesions between time point 1 (SUV(max1)) and time point 2 (SUV(max2)) was calculated. All PET results were correlated with the histopathological or cytopathology results. Patients were divided into three principal groups (A = newly diagnosed MPM, B = recurrent MPM, and C = benign pleural disease). The parameters of 18F-FDG uptake (SUV(max) values and its changes over time) were compared among groups. Among the 55 patients who had undergone dual time point 18F-FDG-PET studies, 44 were diagnosed with MPM (28 newly diagnosed and 16 had recurrence). The PET studies demonstrated 229 malignant pleural lesions in these patients. The remaining 11 patients were proven to have benign pleural disease. The mean +/- SD of the SUV(max1), SUV(max2), and the Delta%SUV(max) of the all lesions of each patient in groups A, B, and C were 5.0 +/- 2.2%, 5.8 +/- 2.8%, and 12.8 +/- 8.4%; 4.6 +/- 1.7%, 5.3 +/- 2.0%, 13.8 +/- 9.2%; and 1.6 +/- 0.4%, 1.4 +/- 0.3%, and-9.6 +/- 19.1%, respectively. The mean +/- SD of the SUV(max1), SUV(max2), and Delta%SUV(max) in patients with both newly diagnosed and recurrent MPM were significantly higher than those of benign pleural disease group (p < 0.0001). For each patient, the most intense (hottest) lesion's SUV(max1), SUV(max2), and Delta%SUV(max) were also compared among the aforementioned groups, and these results again confirmed that MPM lesions had significantly higher values than those of benign pleural lesions (p < 0.0001). There is an increasing uptake of (18)F-FDG over time in pleural malignancies, whereas the uptake in benign pleural disease generally stays stable or decreases over time. Therefore, dual time point imaging appears to be an effective approach in differentiating benign from malignant pleural disease, which increases the sensitivity and is also helpful in guiding the biopsy site for a successful diagnosis.

Autres tumeurs pleurales malignes

Malignant tumors of the pleura are most often diffuse, nethertheless they are sometimes localized. There is an overlap of the radiologic features of the benign and malignant pleural lesions. The differential diagnosis may be difficult, even on histological sample. Imaging allows the diagnosis of pleural involvement, suggests the malignity, guides percutaneous or thoracoscopic biopsies of the pleura, defines extent of the tumor and follows the course of the disease. We will describe the malignant pleural tumors: pleural metastases, pleural involvement of broncho-pulmonary cancer, of lymphoma and leukaemia. Then the rare pleural tumors will be described: malignant pleural fibroma, sarcoma, histiocytoma and hemangiopericytoma.

Percutaneous lung biopsy with a fine bore cutting needle (Vacu-Cut): improved results using drill technique.

Percutaneous transthoracic needle biopsy is used in the diagnosis of pulmonary and pleural lesions. The standard procedure using the Vacu-Cut cutting type of needle is the "thrust" technique in which the needle is rapidly forced through the lesion. In our experience this technique has a low yield of histological biopsy specimens. The diagnostic yield of a new biopsy technique ("drill" technique) using the Vacu-Cut needle was assessed. The series comprised 29 consecutive patients, 23 with localised peripheral pulmonary lesions and six with pleural lesions. The Vacu-Cut 1.2 mm needle was rotated and drilled by hand through the lesion. Biopsy specimens 4-30 mm long were obtained in 20 of the 23 patients with pulmonary lesions; in three patients material was available for cytological examination only. The diagnostic yield in the 18 malignant pulmonary lesions was 89% and in the five non-malignant lesions 80%. Biopsy specimens 10-30 mm long were obtained in all patients with pleural lesions. The diagnostic yield in the four malignant and two non-malignant lesions was 100%. The total diagnostic yield in malignant lesions was 20 of 22 patients and in non-malignant lesions six of seven patients. The diagnostic yield in the entire series was 26 of 29 patients (90%). Pneumothorax occurred in seven of the patients and three needed a chest tube. There was no haemoptysis and no deaths. The drill technique has a high diagnostic yield in both malignant and non-malignant pulmonary and pleural lesions, and is suggested as the ideal biopsy technique when using the Vacu-Cut needle.

Keratin and epithelial membrane antigen immunoreactivity in nonneoplastic fibrous pleural lesions: Implications for the diagnosis of desmoplastic mesothelioma

The histologic distinction between desmoplastic mesothelioma and reactive fibrosis and between biphasic desmoplastic mesothelioma and pleural metastases with desmoplasia can be difficult. The presence of such epithelial markers as keratin and epithelial membrane antigen (EMA) within the fibrous areas of a pleural lesion might be construed as evidence in support of the diagnosis of desmoplastic mesothelioma. To test this hypothesis ten desmoplastic mesotheliomas were studied with monoclonal antisera to keratin and EMA and compared with ten hyaline pleural plaques, 11 pleural scars, five benign localized fibrous mesotheliomas, and eight desmoplastic pleural metastases. Although the hyalinized fibrous areas within the desmoplastic mesotheliomas stained with keratin (ten of ten) and EMA (five of ten), the following reactive fibrous pleural lesions were also positive: plaques (four of ten keratin-positive, five of ten EMA-positive); scars (six of 11 keratin-positive, four of 11 EMA-positive); and fibrosis induced by metastases (six of eight keratin-positive, one of eight EMA-positive). Benign localized fibrous mesotheliomas were keratin- and EMA-negative. This study suggests that both benign and malignant fibrous pleural lesions may be of mesothelial origin and demonstrates the need to determine by histologic criteria whether the spindle cell component is benign or malignant before assessing the significance of its keratin or EMA immunoreactivity. The lack of keratin and EMA staining in benign localized fibrous mesotheliomas might be of use in distinguishing benign localized cellular fibrous mesotheliomas from sarcomatous mesotheliomas.