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[783] Molecular Fixative-Induced Epithelial-Stromal Separation in Prostatic Carcinomas: A Potentially Helpful Feature

P Robinson, M Nadji, N Block, A Morales. University of Miami, Jackson Memorial Hospital, Miami, FL

Background: Epithelial-stromal separation (ESS), commonly known as retraction artifact may occasionally be seen in a number of carcinomas. This microanatomical alteration, however, is not readily discernible in formalin-fixed routinely process tissue. Alcohol-based fixatives on the other hand, amplify this separation to a considerable degree. We investigated the effect of a methanol-based fixative (Molecular Fixative, Sakura) on the microarchitecture of neoplastic and non-neoplastic prostatic tissue.
Design: Parallel blocks of tissue from prostatectomy specimens of 52 patients with biopsy proven prostatic carcinoma were fixed in both 10% buffered formalin and the Molecular Fixative (MF), from twelve to forty-eight hours at room temperature. They were then processed by a microwave-assisted rapid processing system (Xpress, Sakura) and stained with H and E. Adjacent sections from each block were stained for high molecular weight cytokeratin (34BE12, Dako). An additional 676 prostatic needle biopsies that were all fixed by MF were similarly reviewed.
Results: All prostatectomy samples contained both neoplastic and non-neoplastic glands. Of the 676 prostatic needle biopsies, 168 had areas of adenocarcinoma with Gleasons grades of 6 through 9. ESS was observed in the neoplastic glands of 48 (92%) of MF-exposed prostatectomy samples and 164 (98%) of needle biopsies. Conversely ESS was seen in the neoplastic glands of only 4 (8%) of formalin-fixed prostatectomy specimens. Of interest was the presence of partial ESS of individual non-neoplastic glands adjacent to carcinomas in 9 (17%) of prostatectomy samples. This partial detachment corresponded to partial loss of basal cells as revealed by 34BE12 staining.
Conclusions: Epithelial-stromal separation is seen in the neoplastic glands of most prostatic adenocarcinomas that are fixed by the MF. This microanatomic feature could be of diagnostic value in selected cases. It is possible that the partial detachment of benign glands with loss of basal cells may signal an early neoplastic change.
Category: Genitourinary (including renal tumors)

Monday, March 26, 2007

Poster # 79, Monday Afternoon