A correlative study of histology and imprint cytology in the diagnosis of gastrointestinal tract malignancies.

Endoscopic mucosal biopsies from 323 patients (201 from upper gastrointestinal tract and 122 from lower gastrointestinal tract) were studied to correlate the diagnostic efficacy of histology and imprint cytology in the diagnosis of malignant lesions of gastrointestinal tract. Of these 71 were from normal controls, 113 from benign lesions and 131 from malignant lesions. Histology showed no false positive reports but it was false negative in 6 cases (3 in oesophagus, 1 in stomach and 2 from colon). Imprint was false positive in 3 cases (2 oesophagus, 1 colon) and false negative in 2 cases (both oesophagus). The overall diagnostic accuracy of histology and imprint cytology in oesophagus, stomach and lower gastrointestinal tract was 95%, 98%, 98% and 95%, 100%, 98% respectively. When combined, the diagnostic accuracy increased to 98%, 100% and 100% in oesophagus, stomach and lower gastrointestinal tract respectively. The sensitivity, specificity, positive predictive value, negative predictive value and overall diagnostic accuracy for histology and cytology irrespective of the site was 96%, 100%, 100%, 94%, 97% and 98.5%, 97%, 98%, 98%, 98% respectively. Thus imprint cytology can act as an adjunct to bioptic histology to increase the diagnostic efficacy and save the time but definitely it cannot replace it as chances of false positives are high.