THE INTERRELATIONSHIP BETWEEN TUBULAR AND PAPILLARY SECTORS OF TUBULO-VILLOUS COLORECTAL ADENOMAS - COMPARATIVE MORPHOMETRIC ANALYSIS AND EVALUATION OF CELL-PROLIFERATION

In a series of 100 colorectal adenomas, 23 tubulo-villous adenomas wer e individualized through the identification of papillae as structures persisting for more than 100 mu m in serial sections with a connective axis lined with epithelial cells. In these adenomas, the tubular and villous areas with the highest dysplasia were selected, and a morphome tric analysis was undertaken to assess the Index of Structural Atypia, the Nucleo-Glandular Index, and the Nuclear Stratification Index. The AgNor count and the proliferating cell nuclear antigen (PCNA) Label I ndex (LI) also were performed. The overall mean of each of these index es was significantly higher in the villous sector than in the tubular one (P < .001). In 16 cases, the semi-objective method of dysplasia gr adation showed a superior degree in the papillary sector, whereas it s howed an equal degree in the remaining seven lesions. The AgNOR count was significantly different in all cases, with higher values in villou s sectors (P < .05). With the exception of one case, this was confirme d by the PCNA LI. The Stratification Index showed significantly differ ent values in 20 cases, whereas the other morphometric indexes showed a less discriminatory result. Our findings objectively show that the d egree of dysplasia in tubulo-villous adenomas should be analyzed in th e villous sector. The existence of heterogeneous cellular populations has been confirmed both in the structural organization of cells and in some basic parameters such as the cell proliferation rate in colorect al adenomas. Our findings suggest that the occurrence of villous archi tectural growth is a secondary event in a tubular adenoma. Enhanced ce llular proliferation of the villous area allows the progressive substi tution of tubular structures. Copyright (C) 1998 by W.B. Saunders Comp any.