Biopsy Specimens

Percutaneous/transthoracic needle biopsy: performed under X-ray guidance, an 18-gauge needle is inserted with the aid of a spring-loaded firing device. The biopsy is rinsed directly into fixative. Occasional cases require fresh tissue to be sent for microbiological culture. Fresh frozen or glutaraldehyde-fixed tissue may be needed for special investigations (specialised immunohisto-chemistry, electron microscopy).

Endobronchial /transbronchial biopsies: taken at rigid or flexible bronchoscopy. The rigid bronchoscope ranges from 3 to 9 mm in diameter and may be used for straight-ahead viewing or at 30° or 90° for visualization of the upper lobe bronchi. It is essential for complete examination of the trachea as a flexible bronchoscopy may miss lesions. It may also be used for brush cytology, biopsy, and to trap sputum for cytology and culture.

However, it allows visualization of major lobar orifices only and is usually performed under general anaesthetic. Flexible bronchoscopes have outer diameters ranging from 3 to 6 mm. Light is transmitted through fibre optic bundles. The bronchoscope can be attached to a video camera for large-screen display. The working channel allows the insertion of various diagnostic and therapeutic accessories. Biopsy forceps are inserted to obtain bronchial or transbronchial biopsies. Lesions not accessible to direct biopsy can be approached with a brush to obtain specimens for cytological or microbiologic analysis. Needles may also be used for aspiration and biopsy. Flexible bronchoscopy is the endoscopic procedure of choice as it is simple, quick to use, and is performed under local anaesthetic.

Open lung biopsies: obtained at thoracotomy for the assessment of peripheral lung disease.

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