Pulmonary Pathology Online
Percutaneous Needle and Trucut Biopsy Specimens
To identify the nature of suspicious peripheral lung or pleural lesions.
In the diagnosis of benign neoplasms and non-neoplastic lesions. Example: localized pneumonitis, pleural plaques, tuberculous pleuritis, etc.
For both procedures, lesion size, site and technical expertise play an important role in the diagnostic accuracy.
Pleural biopsy can be performed 'blind', with C.T. guidance or at thoracoscopy.
The main indication of pleural biopsy is in the investigation of chronic / recurrent serous effusions.
For certain pleural mass lesions, trucut needle is preferred.
Needle biopsy is usually performed at the time of aspiration.
In general only parietal pleura is sampled - (In case of cavity obliteration visceral pleura and alveolated lung may be present).
For malignant lesions, needle biopsy has a lower sensitivity when compared with serous cytology due to sampling error.
Diagnostic accuracy is best in cases of secondary carcinoma.
Malignant mesothelioma is difficult to diagnose cytologically and on small tissue fragments obtained by needle biopsy.
In these cases, video-assisted thoracoscopic biopsy can be performed and larger tissue pieces obtained.
Complications: Pneumothorax and hemorrhage are minor complications of both procedures. Mortality rate is very low.
Dissemination of malignant cells ('track' cancer) is an important complication in patients with malignant pleural mesothelioma.
Contraindications for a needle biopsy: Bullous emphysema, severe pulmonary hypertension, bleeding diatheses and for suspected vasoformative lesions.
Handling of needle biopsy specimen:
Macroscopic examination is usually of limited value.
Biopsy size is determined by the type of instrument used to obtain them.
It will range from 1-2 mm (for needle biopsies) to 10-15 mm tissue cores.
In trucut needle biopsies, due to the small specimen size, it is advantageous to obtain 4-5 micron sections stained with hematoxylin and eosin.
A number of unstained sections should be placed on agar / saline coated slides suitable for immunohistochemistry.
This prevents recutting the paraffin block with possible loss of important diagnostic material if further sections are required.
Fine needle and trucut biopsies can be considered adequate if the lesion is identified.
For pleural biopsy, sampling of both mesothelial and submesothelial fibroconnective tissue is important.
In addition to morphological assessment a number of special studies can be performed.
As tissue availability in trucut needle specimens is low. It has to be selected according to the morphological diagnosis.
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