Optimizaton of Fixation and Processing of Biopsy Gun Prostate Needle Biopsy Specimens.
Richard J Zarbo, Nilesh Gupta, Ruan Varney, Nelson Main, Sarah Richard, Beverly Mahar, Oleksandr N Kryvenko, Sandra McMahon, Nataliya Draga, Osama Alassi, Adrian Ormsby, Rita D'Angelo. Henry Ford Health System, Detroit, MI
Background: Consistency of nuclear and cytologic detail in prostate needle biopsy specimens is a critical aspect of histopathologic diagnosis. The preanalytic parameters of formalin fixation from time of surgical procedure are largely uncontrolled and inadequate fixation may contribute to less than optimal histology when using same-day rapid tissue processing. To accomodate this unstandardized variable by defaulting to overnight fixation of Biopty gun prostate needle biopsies negates the advantage of rapid cycle processing.
Design: We performed Biopty Gun (Bard Peripherial Vascular, Inc. Tempe, AZ) needle biopsies of fresh clinical prostatectomy specimens to test 18 pathway variations of tissue fixation and processing. Needle (18G) cores obtained from the posterior aspect of glands (8 per side) were 1 mm or less diameter and averaged 15-18 mm length. To control for variation in fixation time and mimic air-drying, cores were placed on saline soaked gauze initially before testing combinations of no fixation other than on processors, timed tissue fixation at room temperature, desktop microwave formalin fixation for 3.5 minutes (Model EBS42850, Energy Beam Sciences, East Granby, CT), controlled heated fixation for 30 minutes at 37°, 45° and 50°C (FixMate, Milestone Medical Technologies, Inc, Kalamazoo, MI/Sirasole, Italy) and processing on two microwave enhanced instruments, Tissue-Tek Xpress (Sakura Finetek USA, Inc, Torrance, CA) and Pathos DELTA (Milestone Medical Technologies). Quality assessments were made of ease of embedding and microtome sectioning and histopathologic variables of hematoxylin and eosin staining intensity, homogeneity, nuclear preservation, nucleolar prominence, autolysis or thermal artifact. Microscopic sections were evaluated by one GU pathologist. Microscopic quality was scored on a 10-part scale.
Results: With the exception of the FixMate heated and timed fixation tests at 37°C and 45°C, all combinations gave inconsistent and spotty unacceptable, suboptimal to good microscopic preparations no matter the variable manipulated. The higher 50°C test of heated formalin fixation resulted in an artifact of nuclear chromatin that was dark and smudgy. The histologic quality at 37°C was judged slightly superior to 45°C. No significant difference in quality of tissue microtomy or histologic preparation was noted for either microwave tissue processor.
Conclusions: Enhanced consistency in the quality of histologic preparations using rapid microwave processors is obtained when prostate needle biopsy fixation is standardized with controlled time and temperature of fixation.
Monday, February 28, 2011 1:00 PM
Poster Session II # 273, Monday Afternoon