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  PAP/NGC Program Review

 

 

 

August 2003
Special Section

What the 2002 nongynecologic cytology data tell us

David C. Wilbur, MD

Each year the data from the nongynecologic cytology survey are compiled and analyzed for overall trends and changes from prior years. This databank is a valuable resource that can be used to identify areas of cytology where interpretational difficulties may arise, and in which improvement via education can be targeted.

In the 2002 databank, responses from 1,311 laboratories were included, constituting the interpretations of 3,145 pathologists and 2,546 cytotechnologists. However, only laboratory responses are considered in the tabulations because this represents the closest simulation of actual practice. Generally, statistics for a given interpretational category are considered for the summary when there are more than 100 responses for significance purposes.

In the 2002 database, we noted a slight improvement in accuracy of interpretation as compared with data from 2001. It is unknown at this time whether this performance is due to better participant performance or to the inclusion of better (more representative) slide challenges in the program.

Several interesting highlights from the data follow:

Effusions
Effusion specimens showed significant false-positive results when chemotherapy or radiotherapy effect were present (21 percent pleural, five percent ascitic). Squamous cell carcinoma in effusion specimens continues to be difficult for participants, with 23 percent of such cases being false-negative in pleural fluids and 31 percent false-negative in ascitic fluids. (Readers are referred to a discussion addressing this at www.cap.org under Cytopathology Unknown Cases.)

Cerebrospinal fluid
Specimens showing benign chronic inflammation prompted false-positive/suspicious interpretations in 26 percent of responses. (Flow cytometric information would be most useful in this differential, and the CAP is exploring the possibility of adding this information to the challenges.)

Pulmonary
Pulmonary hamartomas show a 25 percent false-positive/suspicious rate on FNA.

Breast
Cases of lobular carcinoma are difficult to identify (10 percent false-negative rate) and classify (nearly 50 percent called of ductal origin) on FNA specimens.

Salivary gland
This area remains one of the most difficult FNA interpretations for participants. Pleomorphic adenomas and Warthin’s tumors both showed a seven percent false-positive/suspicious rate. Acinic cell carcinomas and adenoid cystic carcinomas showed high false-negative rates (35 percent and 39 percent, respectively).

Urine
Benign urines with instrumentation effect showed false-positive/suspicious rates of 12 percent.

Lymph node
Reactive lymph nodes showed a 16 percent false-positive/suspicious rate in FNA specimens. (As for CSF, the addition of flow cytometric information may be helpful to participants.)

For further observations, please review the 2002 year-end summary document that will be sent to participants in the Interlaboratory Comparison Program in Nongynecologic Cytopathology. Data such as these form the basis for several differential diagnostic data and slide review projects now underway or recently completed by CAP Cytopathology Committee members. Two articles were published on breast1 and normal cellular elements in fine-needle aspiration specimens.2 An article detailing effusion cytology data has been completed and submitted for publication, and projects detailing salivary gland and thyroid data are in progress. The data compiled in each area form fertile soil for discussions of differential diagnosis. In addition, the data provide insights into the “standard” for interpretation in each area. Such data can have broad utility from educational, research, and medicolegal standpoints. Participants are encouraged to review these data carefully. The committee members appreciate comments and observations.

    References
  1. Young NA, Mody DR, Davey DD. Diagnosis and subclassification of breast carcinoma by fine-needle aspiration biopsy: results of the Interlaboratory Comparison Program in Non-gynecologic Cytopathology. Arch Pathol Lab Med. 2002;126:1453–1457.
  2. Young NA, Mody DR, Davey DD. Misinterpretation of normal cellular elements in fine-needle aspiration biopsy specimens: observations from the College of American Pathologists Interlaboratory Comparison Program in Non-gynecologic Cytopathology. Arch Pathol Lab Med. 2002;126:670–675.


Dr. Wilbur, chair of the Nongynecologic Working Group of the CAPCytopathology Committee, is director of cytology at Massachusetts General Hospital, Boston.