The form factor of alpha-naphthyl acetate esterase-positive cells in non-Hodgkin's lymphomas and reactive lymph nodes.

The shape of alpha-naphthyl acetate esterase (ANAE)-positive cells (other than T lymphocytes) has been measured in 40 lymph nodes. The specimens comprised 15 high-grade lymphomas, 15 low-grade lymphomas and 10 reactive lymph nodes. The parameter used for the measurement of shape was form factor (FF), which is readily calculated by the Reichert-Jung (Kontron) MOP-AMO3 user-controlled image analyzer. Perfectly round cells have an FF value of 1.0, whereas the FF of irregularly-shaped cells diverges from unity. It has been demonstrated that the ANAE-positive cells in high-grade lymphomas have mean values for FF of 0.8-0.9, whereas in low-grade lymphomas and reactive nodes the mean value is 0.4-0.5. Thus, high-grade lymphomas contain many more rounded ANAE-positive macrophage type cells than do low-grade lymphomas and reactive nodes. In the latter two types of specimen there is an excess of branching and spindle-shaped ANAE-positive cells.