Types of gastrointestinal biopsies

Several biopsy techniques have been established to evaluate the GI tract.^1,2,3 Irrespective of the biopsy type collected, the tissue removed should be representative, sufficient, and well preserved.

1.8.2.1 Endoscopic biopsies

Specimens taken by endoscopic forceps are the most com­mon type of GI tract biopsies. They allow accurate sampling of multiple sites and thus are a good compromise between minimal invasion on one hand and sufficient amount of tissue for evaluation on the other. The working channel of endosco­pes commonly range in size from 2.2 to 2.8 mm and deter­mine the size of the biopsy forceps that can be used to collect the samples. Biopsy samples should include samples from dif­ferent areas of the stomach, i. e., cardia, fundus, corpus, antrum, and pylorus, as well as samples from duodenum and if indicat­ed colon. This is not always possible or even indicated depend­ing on the size of the patient or the clinical signs the patient was presented for.

1.8.2.2 Full-thickness biopsies

Surgical excisional and incisional biopsies vary considerably in size ranging from punch samples of a few millimeters in dia­meter to mass lesions measuring several centimeters in diame­ter. Ideally, samples should encompass the whole lesion or at least a representative portion of the lesion. In case of a dissemi­nated process, more than one lesion should be sampled. Also, in order to allow for proper assessment of the disease process all layers of the gastrointestinal wall should be included.

1.8.2.3 Needle biopsies

Samples can also be collected by use of a needle when the lesion cannot be fully represented by endoscopic biopsies. Wide-bore cutting needle samples will be of higher diagnostic value than fine-needle biopsies.

1.8.2.4 Brushing and curettage samples

These samples comprise of exfoliations of individual cells and cell aggregates. Such samples should be investigated by cytol­ogy (see 1.7).

1.8.3