Efficacy of magnifying endoscopy in the differential diagnosis of neoplastic and non-neoplastic polyps of the large bowel.
OBJECTIVE
We have introduced magnifying colonoscopy into clinical practice and analyzed its diagnostic efficacy, especially regarding the ability to distinguish neoplastic from non-neoplastic polyps.


METHODS
The materials consisted of 923 polyps. After identifying the lesions during normal colonoscopy, a dye was sprayed, and then the zoom apparatus of the colonoscope was used to make a magnified observation at a maximum 100 times magnification. We classified the crypt orifices into six categories and labeled them A to F as follows: A, a medium round appearance; B, an asteroid appearance; C, an elliptic appearance; D, a small, round appearance; E, a cerebriform appearance; F, no apparent structural appearance.


RESULTS
Forty-two of 923 polyps did not reveal any clear images of crypt patterns. The percentage of histologically neoplastic change in the lesions classified as A, B, C, D, E, and F were 10, 15.9, 93.7, 100, 94.8, and 87.5 percent, respectively. When we considered types A and B to represent a crypt pattern of non-neoplastic lesions, and types C, D, E, and F to represent neoplastic lesions, and when the lesions that did not show any clear images were classified as a misjudgment, the diagnostic accuracy of neoplastic lesions (sensitivity) was 92 percent and that of non-neoplastic lesions (specificity) was 73.3 percent. Overall, the diagnostic accuracy in differentiating neoplastic from non-neoplastic lesions was 88.4 percent. Twenty-three neoplastic lesions that were misjudged to be non-neoplastic were histologically adenoma with mild atypia in 22 and adenoma with moderate atypia in 1.


CONCLUSIONS
Magnifying colonoscopy was considered to be useful in determining the indications for colonoscopic removal.
Togashi
K
K
Department of Surgery, Jichi Medical School, Kawachi-gun, Tochigi-ken, Japan.
Konishi
F
F
Ishizuka
T
T
Sato
T
T
Senba
S
S
Kanazawa
K
K
D018256:Adenomatous Polyps / Q000175:diagnosis / Q000473:pathology; D001706:Biopsy; D002277:Carcinoma / Q000175:diagnosis / Q000473:pathology; D016009:Chi-Square Distribution; D003111:Colonic Polyps / Q000175:diagnosis* / Q000473:pathology / Q000601:surgery; D020685:Colonoscopes; D003113:Colonoscopy / Q000379:methods*; D004396:Coloring Agents; D003937:Diagnosis, Differential; D005840:Gentian Violet; D006801:Humans; D006965:Hyperplasia; D007089:Image Enhancement / Q000295:instrumentation / Q000379:methods; D007203:Indigo Carmine; D007413:Intestinal Mucosa / Q000473:pathology; D010580:Peutz-Jeghers Syndrome / Q000175:diagnosis / Q000473:pathology; D012680:Sensitivity and Specificity
D004396:Coloring Agents; D007203:Indigo Carmine; D005840:Gentian Violet