89

were equivocal in two small cell carcinomas, and negative in all other lung tumors. In overall diagnostic acuity, periodic acid-Schiff-lead hematoxylin equals electron microscopy, surpasses argyrophilia, serotonin fluorescence, and immunolocalization of polypeptide hormones. It is approached only by antineuron-specific enolase immunoreactivity.

Human Lung Tumours May Coexpress Dif- ferent Classes of Intermediate Filaments. Garter, K.C., Dunnill, M.S., Van Muijen, G.N.P., Mason, D.Y. Nuffield Department of Pathology, John Radcliffe Hospital, Oxford OX3 9DU, UK. J. Clin. Pathol. 39: 950-954, 1986.

Ninety four pulmonary neoplasms were examined immunocytochemically with two or three different monoclonal antibodies against the intermediate filament proteins cytokeratin, neurofilament, vimentin, and desmin. In normal tissues these have a different and non- overlapping distribution, and it is generally believed that tumours maintain the same pattern of expression as the tissues from which they arise. In this report, however, the coexpression of at least two (and less commonly three or four) different intermediate filaments was seen in 40% (37 of 94) of the cases of lung cancer. These results, especially if confirmed in other common types of human malignancy, have considerable im- plications for the use of anti- intermediate filament antibodies in diag- nostic pathology.

5. CLINICAL ASSESSMENT

Bronchoscopy. Sanderson, D.R. Division of Thoracic Dis- eases and Internal Medicine, Mayo Clinic and Mayo Foundation, Rochester, MN, U.S.A. Br. Med. Bull. 42: 244-248, 1986.

Bronchoscopy is an essential part of contemporary pulmonary medicine and surgery. Topical anaesthesia is often adequate, although general anaesthesia may be preferred for prolonged examina- tions or in children. Preoperative evaluation of suspected malignancy in- cludes staging and determination of his- tologic cell type. Many diffuse intersti- tial lung diseases are amenable to diag- nosis by transbronchoscopic biopsy of lung parenchyma (TBLB) and bronchoal- veolar lavage (BAL). These techniques are especially effective for evaluating pul- monary infiltrations in immunocompromised patients and may obviate the need for open lung biopsy in some seriously ill patients. Therapeutic application, such as suctioning of retained secretions un- der direct vision, is highly effective in the critical care setting. Palliative therapy of malignant airway obstruction with Nd:YAG laser and brachytherapy are new and important development in broncho- scopic practice.

Mediastinoscopy Trastek, V.F., Piehler, J.M., Pairolero, P.C. Section of Thoracic and Cardiovas- cular Surgery, Department of Surgery, Mayo Clinic and Mayo Foundation, Rochester, MN, U.S.A. Br. Med. Bull. 42: 240-243, 1986.

Mediastinoscopy was first recommended by Carlens in 1959 as an invasive endo- scopic technique to evaluate the mediastinum. It is most frequently used to diagnose mid mediastinal masses and to stage bronchogenic carcinoma. It can be performed with minimal mortality and mor- bidity in the hands of experienced personnel. Controversy still exists whether this procedure should be used routinely or selectively in staging a patient with bronchogenic carcinoma. It has been, and will c~ntinue to be. useful technique in the evaluation of the mediastinum.

Comparative Studies of Computerized Tomography and Mediastinoscopy for the Staging of Bronchogenic Carcinoma. Rhoads, A.C., Thomas, J.H., Hermreck, A.S., Pierce, G.E. Department of Surgery, University of Kansas College of Health Sciences and Medical Center, Kansas City, KS 66103, U.S.A. Am. J. Surg. 152: 587- 590, 1986.

The accuracy of mediastinal com- puterized tomographic scans for the stag- ing of bronchogenic carcinoma varies be- tween institutions. In the present study, the sensitivity rate was 57 percent, the specificity rate 69 percent, and the overall accuracy rate 64 percent, all of which were generally lower than rates reported in the recent literature. Dif- ferent scanning equipment, diagnostic criteria, and patient populations may all contribute to this variance. The data in this report suggest that tumor histologic type and location also influenced the ac- curacy of computerized tomography. On the basis of this study and review of the literature, it is recommended that any given institution assess the accuracy of its own computerized tomographic medias- tinal scans before substituting scanning for mediastinoscopy in the preoperative staging of bronchogenic carcinoma.

Standard and Computed Tomography in the Evaluation of Neoplasms of the Chest: A Comparative Efficacy Assessment. Inouye, S.K., Sox, H.C. Jr. Department of Internal Medicine, Yale University School of Medicine, New Haven, CT, U.S.A. Ann. Intern. Med. 105: 906-924, 1986.

Although in practice computed tomog- raphy (CT) has nearly replaced standard tomography in the evaluation of chest diseases, an analysis of the literature shows that standard tomography may be preferred in some settings. After a detailed review of studies on test performance, we calculated overall sen- sitivity and specificity values. Using Bayesian analysis, we then developed