| Theme | Histopathological Diagnosis IIc Type of Colorectal Cancer | |
|---|---|---|
| Title | Colorectal tumor surface structure by scanning electron microscopy (SEM) | |
| Publish Date | 1998/03 | |
| Author | Yasushi Sano | 2nd Department of Pathology, Dokkyo University School of Medicine |
| [ Summary ] | Recently, recognition of the molecular analysis of colorectal tumor has advanced significantly. In flat type colorectal cancer, point mutations of the ras oncogene are not involved. Flat type cancer might be a new cancer which develops via a different pathway and might be a candidate for de novo carcinogenesis. Clinicopathologically, stereomicroscopic classification of colorectal tumors has been studied by many authors. However, little is known about the scanning electron microscopic (SEM) characteristics of flat type colorectal tumors. A total of 21 flat type colorectal turnorous lesions resected surgically or endoscopically were analyzed. Each lesion was divided into two pieces, one for histopathologic analysis, and the other for SEM observation. In this report we also showed a new finding regarding the evolution of small adenoma using SEM, and proposed a new hypothesis for the development of so-called IIa+depression type adenoma. This type of adenoma surrounds the normal colonic cells, and expands over them. Morphologically, elongated and tubular crypt orifices can be seen among the normal colonic mucosa which shows round crypt orifice and is demarcated like the Pentagon under SEM observation. We named this finding "pentagon appearance". Histologically, the two layer structure can be seen on the margin of this type of adenoma. In conclusion, it is suggested that observation of the colorectal tumor surface structure by SEM is quite useful for assessing of the nature, growth and progression of these tumors. |
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