Cytology and histology: Complementary diagnostic modalities during endoscopic ultrasound-guided tissue acquisition

Endoscopic ultrasound-guided fine needle aspiration (FNA) has become the preferred method of sampling accessible intraintestinal and extraintestinal abdominal masses, as well as peri-intestinal lymphadenopathy. Despite the success of endoscopic ultrasound-guided-FNA, there are settings in which FNA appears to underperform when compared to other techniques. To overcome some of the limitations of FNA, endoscopists have used small-gauge cutting and core needle biopsies in conjunction with or as an alternative to FNA. This review, from the pathologists′ perspective, will cover these complementary techniques, including definitions, advantages, and limitations, as well as the role of rapid on-site evaluation. Our conclusions include that cytologic specimens, which use alcohol-based fixation during processing, appear preferable for molecular testing that relies on nucleic acid preservation, such as next-generation sequencing. However, core biopsy should be considered when immunohistochemistry and tissue architectural details are required for diagnosis.