Differential diagnosis between mycosis fungoides and chronic dermatitis by fractal analysis

In this study we compared the diagnostic power of NCI to that of fractal geometry applied, at transmission electron microscopy level, as a tool to analyze the nuclear contour of lymphoid cells. The resulting mean D was always greater than the topological dimension (P<0.001) and the coefficient of determination of the linear fits had R2 value >0.95, showing the fractal approach appropriated (the mean ranges of scales for which linear log-log plot were found were between 100 and 700 nm). Both D and NCI were found to be significantly higher in MF (D=1.21+0.03; median =1.22; range 1.16-1.28 NCI=7.6+0.6; median =7.4; range 6.7-8.2) than in CD (D=1.11+ 0.02: median=1.11; range 1.05-1.14; NCI= 6.1+0.4; median=5.8; range 5.6-7.3) (Fig. 2, P<0.001). D significantly differed between nuclei showing NCI<7 (D=1.09+0.02, #=705) and nuclei with NCI>7 (D=1.19+0.02; #=520) (P<0.001). A significant positive correlation was found between D and NCI (r=0.75, P<0.001). The variance of D values was three times lower than that of NCI values (MF: 2.5 vs. 8%; CD: 1.9 vs. 6.9%, PB/0.01, PB/0.01, respectively). We suggest that fractal analysis could be an additional tool in the challenging differential diagnosis between benign dermatitis and early stage MF.