| How does the grading of papillary tumors described above differ
from the original WHO grading system? The criteria for diagnosing papillomas
and grade II and III carcinomas have not changed. What we previously called
grade I papillary carcinoma has been split into two groups: those with nuclear
atypia, as described above, remain grade I carcinoma; those with epithelium
thicker than that of papilloma are now the papillary urothelial neoplasms
of low malignant potential. It should be noted that some centers use a different
grading system and this may be correlated with the one we use as follows:
grade I tumors are called "low grade," and grade II and III tumors are classified
as "high grade." [45]
When classifying and grading papillary tumors, we believe the critical
distinction to be made is between grade II and III tumors on the one hand
and the papillomas, PUNLMP's, and grade I tumors on the other. |
