Mitosis counting in XXXX : an exercise of questionable significance.

@entity5 @entity1 @entity4797
Two pathologists reviewed and classified 45 cases of @entity4797 , evaluating each case for multiple histologic variables, including mitotic rate. In addition to recording the mitotic count for each of thirty 0.1963-mm2 high-power fields, the investigators recorded the distribution of mitotic counts in many non-spermatocytic @entity4797 . Statistically significant differences for mitotic rate in the nonspermatocytic @entity5 were noted between the observers; one observer found a mean mitotic rate of 1.815/high-power field for 43 @entity5 , whereas the other noted a mean mitotic rate of 1.388/high-power field (p = 0.001). These differences led to disagreement on the classification of 3 @entity5 . Of the 4 cases considered to be high-mitotic-rate @entity4797 by one or both observers, all @entity1 had presented with stage I disease. Three of the @entity1 were followed up for 23, 55, and 56 months, and all were free of disease; the fourth was lost to follow-up. The @entity1 with the highest mitotic rate was free of disease at 55 months of follow-up. On the basis of our findings we question the value of the designation high-mitotic-rate @entity4797 . Analysis of the distribution of mitotic counts within the @entity5 revealed them to be Poisson distributed. With these data and other empirically derived data, it was possible to estimate the probability of misclassification of @entity4797 based on mitotic rate, the diagnostic mitotic rate threshold, and the number of fields counted for mitoses. Similar analysis might be valuable for other @entity5 , particularly those of smooth muscle origin, in which mitotic rate is of diagnostic or prognostic value.
