Pap stain, high power
Note the irregularity of nuclei and high N:C ratio in this cluster of low grade papillary carcinoma
Pap stain, high power
Cluster with irregular outline. Note the cells have homogenous cytoplasm and nuclei show slight variation in size and slight irregularity in outline
Pap stain, low power
Two clusters with irregular outlines. Irregular outlines are usually (but not always) seen in low grade urothelial carcinoma
Pap stain, high power
A cluster of cells with irregular borders. Note the variation in nuclear size, slight nuclear irregularity and indistinct nucleoli. The cytoplasm is homogenous.
These features favor low grade carcinoma over reactive changes; however, definitive diagnosis should be made only on biopsy
Pap stain, medium power
Cluster with scalloped margins and the cells show central nuclei. Concurrently obtained biopsy in this case showed multiple papillary low grade urothelial carcinoma lesions.
On cytology, however, the lesion is indistinguishable from stone related or instrumentation related atypia
Pap stain, high power
Low grade urothelial carcinoma cell with irregular nucleus and nuclear grooves. Note that unlike high grade carcinoma, the cell is not hyperchromatic and the chromatin is fine rather than coarse
Features
• Variable cellularity
• Predominantly cohesive groups
• Groups have irregular outlines, compared to reactive groups
• Papillary groups with fibrovascular cores, if present, are diagnostic
• Homogenous cytoplasm
• Slight increased nucleus to cytoplasmic ratio
• Central or eccentrically located nucleus
• Slight irregular nuclear contours
• Usually no nucleoli
• Finely granular chromatin
• In most cases, the features show significant overlap with reactive atypia. Therefore, the diagnosis of Urothelial cell groups with atypia is advised with a comment stating the differential diagnoses.
Whisnant RE et al. Diagn Cytopathol. 2003 Apr;28(4):186-90.
Renshaw AA. Cancer. 2000 Aug 25;90(4):222-9.