Cell block processing is optimal for assessing endoscopic ultrasound fine needle aspiration specimens of pancreatic mucinous cysts

Abstract

<jats:sec><jats:title>Aims</jats:title><jats:p>The cell block technique for assessing endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) specimens from pancreatic mucinous cystic lesions (MCLs) was systematically evaluated for the first time, including comparisons with three traditional methods of assessing such specimens.</jats:p></jats:sec><jats:sec><jats:title>Methods</jats:title><jats:p>The prospective arm comprised EUS-FNA specimens from EUS-suspected pancreatic MCLs. The retrospective arm comprised EUS-FNA specimens from pancreatic MCLs surgically resected before the study start. For each specimen, these data points were collected: macroscopic likelihood of mucin, cyst fluid carcinoembryonic antigen (CEA) level and presence of mucin in air-dried, direct smears and in cell block preparations.</jats:p></jats:sec><jats:sec><jats:title>Results</jats:title><jats:p>The prospective and retrospective arms of the study comprised 80 and 30 EUS-FNA specimens, respectively. Seven prospective cases led to surgical resections during the study, and therefore, 37 EUS-FNA specimens were confirmed to have originated from MCLs. In the prospective arm, macroscopic mucin was suspected, cyst fluid CEA level exceeded 192 ng/mL, mucin was detected in direct smears and cell block preparations in 78%, 30%, 39% and 73% of cases, respectively. Of the 37 specimens confirmed to originate from MCLs, macroscopic mucin assessment, cyst fluid CEA level, direct smear mucin assessment and cell block mucin assessment had sensitivities for diagnosing MCL of 87%, 45%, 45% and 81%, respectively.</jats:p></jats:sec><jats:sec><jats:title>Conclusions</jats:title><jats:p>Cell block preparations are as likely to identify mucin from pancreatic MCLs as macroscopic assessment but are twice as likely to diagnose MCL than direct smears and fluid CEA biochemistry. The cell block technique is easy for sample collection and processing especially because these are identical for solid and cystic pancreatic lesions.</jats:p></jats:sec>

My approach to endoscopic ultrasound-guided fine-needle aspiration biopsy specimens of the pancreas

“…The assessment of an EUS-FNAB specimen for MCL can be divided into that for mucin and that for cellular material. The author demonstrated, in a recent and predominantly prospective study, that tissue/cell block preparation is superior to direct smears in demonstrating mucin in this context 4. This study’s findings and the author’s additional experiences confirm that Alcian blue periodic acidic Schiff (ABDPAS) staining is essential for mucin assessment in EUS-FNAB tissue/cell block preparations.…”

“…There are much less data on whether tissue/cell block preparation can be successfully applied to EUS-FNAB samples from pancreatic cystic lesions. However, this author has recently documented that, with such samples from pancreatic mucinous cysts, tissue/cell block preparation is superior to direct smears in demonstrating mucin and shows higher diagnostic sensitivity than cyst fluid carcinoembryonic antigen (CEA) biochemistry 4. The author is not aware of any published direct comparison between tissue/cell block preparation and cytospin and/or LBC for processing EUS-FNAB samples from pancreatic cystic lesions.…”

Diagnostic role of endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) in abdominal lymphadenopathy of unknown etiology

“…Previously, it was believed that the quantity of tissue obtained via aspiration significantly impacted the positivity rate of the procedure. Some studies indicate that smaller gauge needles (22G or 25G) provide smaller material volumes compared to larger gauge needles (19G), yet they are associated with reduced bleeding risk and increased maneuverability, thereby allowing for more accurate diagnoses (35)(36)(37). The 2017 ESGE sampling guidelines recommend utilizing a 25G or 22G needle for LN sampling (20).…”

Application of EUS-based techniques in the evaluation of pancreatic cystic neoplasms

“…Cell block preparations are two times more likely to diagnose MCNs than are direct smears and fluid CEA biochemistry. [ 90 ] Cell block techniques may be a better specimen processing method than standard smear cytology. However, the data supporting the cell block technique as a routine process are scarce, which limits the wide utilization of the technique.…”