General/Default Categories
These old standby categories are the default for Non-GYN specimens without reporting systems and are actually also used by the WHO for biliary and respiratory specimens (e.g., BAL, Brush).
– Non-diagnostic
– Negative for Malignancy
– Atypical
– Suspicious for Malignancy
– Malignant
Urine Cytology
Use the Paris system, which has the following primary categories (Acta Cytologica (2016) 60 (3): 185–197.)
– Non-diagnostic/Unsatisfactory
– Non-diagnostic/Unsatisfactory, Low-cellularity specimen
– Non-diagnostic/Unsatisfactory, Obscuring inflammation/lubricant [select obscuring agent]
It’s thought that 2 well-visualized urothelial cells per high-power field in 10 consecutive high-power fields may serve as an objective measure of adequacy in instrumented urine specimens processed using the ThinPrep method.
Regardless of the specimen type (voided urine or instrumented), if the urothelial cells are completely obscured by lubricant or inflammatory cells, this represents an ‘unsatisfactory’ specimen. Conversely, if there are any atypical cells regardless of the overall cellularity this represents a satisfactory specimen.
– Negative for High-grade Urothelial Carcinoma
– Atypical Urothelial Cells
– Suspicious for High-grade Urothelial Carcinoma
– High-grade Urothelial Carcinoma
– Low-grade Urothelial Carcinoma
Anal Pap Smears
Use the Bethesda system and CAP Protocol for the Reporting of Anal Cytology Specimens:
– Unsatisfactory for evaluation, Insufficient nucleated squamous cellularity
– Unsatisfactory for evaluation, Obscuring blood/inflammation/acellular material [pick limiting factor]
– Negative for intraepithelial lesion or malignancy (NILM)
– Transformation zone present/absent
– Atypical squamous cells – undetermined significance (ASC-US)
– Transformation zone present/absent
– Atypical squamous cells cannot exclude High-grade squamous intraepithelial lesion (ASC-H)
– Transformation zone present/absent
– Low-grade squamous intraepithelial lesion (LSIL)
– Transformation zone present/absent
– High-grade squamous intraepithelial lesion (HSIL)
– Transformation zone present/absent
– Squamous cell carcinoma
– Transformation zone present/absent
– Atypical glandular cells
– Transformation zone present/absent
Effusion Cytology
In general, use the “The International System for Serous Fluid Cytopathology”
Non-diagnostic
– Non-diagnostic
COMMENT: The specimen is paucicellular and there are insufficient cellular elements for a cytologic interpretation.
Additional explanation/detail can be added too:
– Non-diagnostic, Exclusively blood
– Non-diagnostic, Acellular specimen
Negative for malignancy
– Negative for malignancy
and any additional secondary diagnoses that may be helpful, such as
– Abundant acute inflammation
– Abundant chronic inflammation
Atypical
– Atypia of undetermined significance
COMMENT: There are rare cells with mild atypia, which are uncertain significance.
– Atypical lymphoid infiltrate (see comment)
COMMENT: There are abundant lymphocytes present. While these could represent chronic inflammation, if there is concern for a lymphoproliferative disorder, future specimens could be sent fresh for flow cytometry immunophenotyping as clinically necessary.
– Atypical mesothelial proliferation (see comment)
COMMENT: There are numerous large clusters of atypical cells that stain with multiple markers of mesothelial differentiation. While these findings raise the possibility of mesothelioma, this diagnosis is challenging to make on cytology specimens. Accordingly, material is being sent for BAP1 immunohistochemistry and P16 FISH to evaluate as abnormal results could further support the diagnosis of mesothelioma. Clinical and radiographic correlation is recommended.
Suspicious
– Suspicious for malignancy
COMMENT: There are rare cells with moderate to marked cytologic atypia. These cells raise suspicion for malignancy, but their limited presence precludes a definitive diagnosis and additional analysis. Clinical correlation is recommended, with possible consideration for additional sampling as clinically indicated.
Malignant
– Malignant
– Metastatic carcinoma, consistent with *** origin (see comment)
COMMENT: The cell block shows ***. A panel of immunohistochemical stains demonstrates that these cells stain with ***. Together, these findings are diagnostic of metastatic carcinoma and are consistent with *** origin. Clinical and radiographic correlation is recommended.
– Metastatic high-grade carcinoma, consistent with Mullerian origin (see comment)
COMMENT: The cell block shows malignant cells with high N:C ratios, irregular hyperchromatic nuclei, and prominent nucleoli. These cells stain positive for Ber-EP4, PAX8, WT-1, and strongly diffusely for P53 and P16. The morphologic and immunoprofile supports a diagnosis of high-grade serous carcinoma of tubo-ovarian origin. Clinical and radiographic correlation is recommended.
– Positive for serous neoplasm (see comment)
COMMENT: The patient’s history of an ovarian mass is noted. The cytology preparations show clusters of epithelial cells with only mild atypia. These cells stain positive for Ber-EP4, PAX8, WT-1. There is wild-type staining with p53. Together, these findings are diagnostic of involvement by a serous neoplasm and are suggestive of a serous borderline tumor or related tumor. Correlation with the pending surgical pathology specimen is recommended.
Last updated: 4/14/26