BACKGROUND: The goal of this study was to clarify morphogenetic development in colorectal neoplasms with depressions by examining isolated crypts and their pit patterns. METHODS: Twelve colorectal neoplasms with depressions were examined endoscopically, stereomicroscopically, and histopathologically. The pit pattern was defined according to Kudo's classification. The HCl digestion method was used to isolate the crypts. For scanning electron microscopy observations of the surface structure, specimens were mounted on brass stubs, coated with gold, and then observed. RESULTS: In isolated crypts with bifurcation extending to the middle or all the way to the lesion surface, the crypt orifice was round with a type IIIS pit pattern. In those with bifurcations extending up to the upper portion, the crypt orifice was oval with a type IIIS pit pattern. Some crypts were almost completely separated into two. The orifice diameter of a nonbifurcated crypt was 95.1 +/- 28.1 microm, whereas the diameters of crypts with bifurcations extending to the middle or the upper part were 114.7 +/- 40.8 and 208.1 +/- 71.4 microm, respectively. Thus, the orifice diameter of a crypt with the bifurcation reaching the upper part was about twice that of orifices of nonbifurcated crypts or those with bifurcations extending to the middle. CONCLUSIONS: Our results indicate that colorectal neoplasms with depressions may enlarge by a process of crypt bifurcation in which a single crypt divides into two crypts.
BACKGROUND: The goal of this study was to clarify morphogenetic development in colorectal neoplasms with depressions by examining isolated crypts and their pit patterns. METHODS: Twelve colorectal neoplasms with depressions were examined endoscopically, stereomicroscopically, and histopathologically. The pit pattern was defined according to Kudo's classification. The HCl digestion method was used to isolate the crypts. For scanning electron microscopy observations of the surface structure, specimens were mounted on brass stubs, coated with gold, and then observed. RESULTS: In isolated crypts with bifurcation extending to the middle or all the way to the lesion surface, the crypt orifice was round with a type IIIS pit pattern. In those with bifurcations extending up to the upper portion, the crypt orifice was oval with a type IIIS pit pattern. Some crypts were almost completely separated into two. The orifice diameter of a nonbifurcated crypt was 95.1 +/- 28.1 microm, whereas the diameters of crypts with bifurcations extending to the middle or the upper part were 114.7 +/- 40.8 and 208.1 +/- 71.4 microm, respectively. Thus, the orifice diameter of a crypt with the bifurcation reaching the upper part was about twice that of orifices of nonbifurcated crypts or those with bifurcations extending to the middle. CONCLUSIONS: Our results indicate that colorectal neoplasms with depressions may enlarge by a process of crypt bifurcation in which a single crypt divides into two crypts.