| Theme |
Prevalence of the IIc type colorectal neoplasm |
| Title |
Incidence of IIc and IIc combined types submucosal colorectal carcinomas and their histological characteristics |
| Author |
Kazuhiko Shioji |
Division of Molecular and Diagnostic Pathology, Graduate School of Medical and Dental Sciences, Niigata University |
| Author |
Yoichi Ajioka |
Division of Molecular and Functional Pathology, Graduate School of Medical and Dental Sciences, Niigata University |
| Author |
Hidenobu Watanabe |
Division of Molecular and Diagnostic Pathology, Graduate School of Medical and Dental Sciences, Niigata University |
| Author |
Akito Sato |
Division of Molecular and Diagnostic Pathology, Graduate School of Medical and Dental Sciences, Niigata University |
| Author |
Satoshi Hashimoto |
Division of Molecular and Diagnostic Pathology, Graduate School of Medical and Dental Sciences, Niigata University |
| [ Summary ] |
Macroscopically diagnosed IIc and IIc combined type (IIc+IIa or IIc+Is) submucosal colorectal carcinomas (sm-Ca) were classified into the absolutely depressed (ABS) (truly depressed tumor) or relatively depressed (REL) (pseudo depression compared to the surrounding marginal elevation) types by histological examinations. Each incidence and its histological characteristics were analyzed. Out of 468 surgically resected sm-Ca, IIc and IIc combined type comprised 66/468 (14.1%). Out of 66 tumors, the ABS and REL type comprised 21 (31.8%) and 45 (68.2%), respectively. In sm1 cancers, the incidence of IIc and IIc combined type was 16/123 (13.0%) and that of the ABS type was 8/123 (6.5%). The ABS type was comprised of the 3 IIc type and the 5 IIc+IIa type. Those of the REL type were considered to be the 8 IIc+IIa type. The average size of tumors was small in the ABS type (12.5mm) compared to those of REL type (19.8mm) and other macroscopic types (21.3mm). The width of IIc mucosa was thinner and thicker than the surrounding normal mucosa in ABS and REL types, respectively. The IIa area of the ABS type consisted of reactive hyperplastic mucosa (5/5) while that of REL type consisted of a neoplastic component (6/7). In sm2,3 cancers, the incidence of IIc and IIc combined type was 50/345 (14.5%) and that of the ABS type was 13/345 (3.8%). The ABS type was comprised of the 3 IIc type and 10 IIc+IIa type. Those comprising the REL type were 31 IIc+IIa type and 6 IIc+Is type. The average sizes of the ABS type was (17.5mm) and the REL type was (14.7-15.5mm), which were significantly smaller than those of other macroscopic types (25.8mm). However, those was no significant difference between The sizes of the ABS and REL types. In the ABS type, 9/13 showed remnant IIc mucosa, the width which was thinner than the surrounding normal mucosa in 8/9. The IIa area consisted of reactive hyperplastic mucosa in 8/10. In the REL type, the IIc area was ulcerated and no remnant mucosal component was present in 26/31. The IIc area was elevated higher thanthe normal mucosa, due to cancerous masses in the submucosa. The IIa and I the area of the REL type were composed of hyperplastic reactive mucosa in 24/31 and 6/6, respectively. These results indicate that macroscopically diagnosed IIc or IIc combined type sm-Ca would contain only 30% of ABS (truly depressed) tumors and other 70% (REL type) would be termed elevated tumors in their nature. The histological characteristics are different between the two types of tumors. For the study of IIc or IIc combined type early colorectal cancers, it is required that we verify by histological examination whether or not the study includes the ABS type alone or both ABS and REL types. |