Complete histologic serial sectioning of a prostate gland with adenocarcinoma.

Variations in the proportion of surface occupied by tumor (percentage carcinoma), carcinoma volume, histologic grade, capsular penetration, and margin positivity were assessed in a completely sampled cancerous prostate gland. All prostatic tissue was embedded and each block serially sectioned, for a total of 2,678 histologic sections examined. Although variations in percentage carcinoma and carcinoma volume were noted in some blocks, the differences were small when compared with the initial set of 19 slides. Histologic Gleason's grade also showed little variation in the serial sections. Focal capsular penetration in one block and an increase in the number of blocks with a positive anterior margin from two to four were identified in serial sections, but this did not alter the pathologic stage because of seminal vesicle involvement by tumor. In this example, the morphologic prognosticators of tumor volume, histologic grade, margin positivity, and pathologic stage were not altered by complete serial sectioning.