Endoscopy: Pit Pattern Diagnosis

Fig. 2.1

Magnified image of normal mucosa in colon. We can recognize roundish pits as normal crypts

../images/461529_1_En_2_Chapter/461529_1_En_2_Fig2_HTML.png — Fig. 2.2

Typical type II pit pattern consists of star-like or onion-skin-like surface structure (left). Type II-open pit pattern whose crypt opened with mucin producing is a characteristic finding of SSA/P (right)

../images/461529_1_En_2_Chapter/461529_1_En_2_Fig3_HTML.png — Fig. 2.3

Type IIIs pit pattern consists of tiny tubular or roundish pits, which are smaller than normal crypts of around mucosa

../images/461529_1_En_2_Chapter/461529_1_En_2_Fig4_HTML.png — Fig. 2.4

Type IIIL pit pattern is composed of long tubular crypts (left). These are sometimes mixed with normal crypts in the inner area (right)

../images/461529_1_En_2_Chapter/461529_1_En_2_Fig5_HTML.png — Fig. 2.5

Type IV pit pattern refers to a sulcus-, branch-, or gyrus-like surface structure

../images/461529_1_En_2_Chapter/461529_1_En_2_Fig6_HTML.png — Fig. 2.6

Type VI pit pattern is similar to type IIIL, IIIS, and IV, but consists of disorder of the array, a size disparity, and asymmetry. The one with less of these irregularities is considered “low grade” (left), and the one with more irregularities is considered “high grade” (right)

../images/461529_1_En_2_Chapter/461529_1_En_2_Fig7_HTML.jpg — Fig. 2.7

Type VN pit pattern refers to lost (left) or broken down (right) surface structure

2.3 Qualitative Diagnosis and Invading Depth Diagnosis

We can diagnose a lesion using magnifying endoscopy based on pit pattern classification in vivo without performing a biopsy of the lesion. The proper rate of discrimination was reported to be approximately 96–98% between tumors and non-tumors and 70–90% between adenoma and cancer. Thus, a qualitative diagnosis with high accuracy can be achieved with magnifying endoscopic observation [5–10].

It is necessary to diagnose the degree of submucosal invasion before performing endoscopic treatment in early colorectal cancer. The risks of vascular infiltration and lymph node metastasis are proportional to the vertical depth of submucosal invading cancer (T1). Moreover, to perform accurate pathological evaluation of endoscopically resected specimens, it is important to indicate the location of submucosal invading. Therefore, in the case of deep T1 cancer, endoscopic treatment is more likely to result in incomplete excision, and surgical treatment must be performed after endoscopic treatment [11].

The proper rate of discrimination of submucosal massive invading was reported to be approximately 70–80% by non-magnifying endoscopy [12, 13].

On the other hand, pit pattern diagnosis using magnifying endoscopy showed that the proper rate of discrimination was about 90% when the Vn type was used as an indicator. However, the rate of protruded type lesions tends to be slightly lower than that of flat type lesions. Since diagnostic accuracy differs according to the macroscopic type and growth type of the lesion, appropriate diagnostic methods (IEE, EUS, etc.) should be combined as the situation requires [14–16].