1987 Volume 78 Issue 9 Pages 1580-1583
The prognosis of anaplastic seminoma has remained controversial, but the diagnosis has been confirmed based on the histologic characterisitics. Among the histologic features of anaplastic seminoma such as increased mitotic activity, cellular irregularity and nuclear pleomorphism, Mostofi stressed that “increased mitotic activity (i.e. 3 or more mitotic figures per high power field) is the single most important, easily recognizable, and reliable feature”, and his criteria have been generally accepted.
However, in our observations of 43 testicular pure seminomas, 32 cases (74%) had 3 or more mitoses per high power field. It was considered that this high proportion was aroused from the difference of the width of visual field of the microscope, and the improvement of the mitotic index in order to correct the difference of microscopes was necessary.
Our study on the correlation between the counts of mitotic figure and seminoma cell revealed the mitotic rate (the count of mitotic figure/the count of seminoma cells×100) well corresponded to the result of measuring the mitotic figures in high power field, and a mitotic rate of 0.5% or more was an indication of anaplastic seminoma.
We propose that the mitotic rate is a possible new criterion for diagnosis of anaplastic seminoma.
