Guided Percutaneous Cytology of Pancreatic Masses A Cytohistological Correlation

Abstract

Objective:  To determine the diagnostic accuracy, usefulness and limitations of ultrasound guided FNAC of pancreatic masses.

Design:  Cross-sectional analytical (comparative study).

Place and Duration of Study:  Department of Histopathology, Sheikh Zayed Hospital Lahore, Study Period - 2 Years.

Materials and Methods:  A total of 26 pancreatic masses were subjected to FNAC from January 2000 to December 2001. Adequate aspirates were obtained in all the cases, without any discrimination of age and gender. The smears were stained with Haematoxylin and Eosin (H & E), Papanicolaou staining (PAP) and May Grun-wald Giemsa stain (MGG). Results of FNAC were categorized as benign tumours (group I), malignant tumours (group II) and non-neoplastic/inflammatory lesions (group III). Tissue biopsy specimens from the same 26 patients were also obtained at the time of FNAC and stained with routine H & E staining. Histology was taken as the gold standard.

Results:  On histological examination 12 of the 26 cases were categorized as malignant tumours, 8 as benign tumours and 6 as non-neoplastic/inflammatory lesions. Out of the 12 malignant cases FNAC picked up 9 cases. Rest of the 3 cases had a false negative diagnosis for malignant tumours. In addition one case had a false negative diagnosis for benign tumour, but no false positive diagnosis was made. Malignant tumours revealed a sensitivity of 75% and diagnostic accuracy of 83.3% while benign tumours showed a 87.5% sensitivity and 92.86% diagnostic accuracy. Non-neoplastic lesions revealed a 100% sensitivity and diagnostic accuracy. A 100% specificity was obtained for both neoplastic and non-neoplastic lesions. The cytological results were statistically evaluated and the diagnostic accuracy was ascertained by calculating sensitivity, specificity, positive predictive value and negative predictive value in accordance with methods employed by Galen and Gambino¹.

Conclusion:  Majority of the pancreatic tumours, both benign and malignant can be categorized on FNAC, with a high degree of accuracy, but since due to a relatively high incidence of false negative diagnosis, good quality preparations, with adequate cellular content, and cytohistological correlation is necessary.

Key Words:  FNAC, benign, malignant, non-neoplastic