Three-dimensional reconstruction and fractal geometric analysis of serrated adenoma

Quantification of morphology of canine circumanal gland tumors: a fractal based study

Circumanal gland tumors are very common neoplasms of dogs. Their classification relies on microscopic examination and is further supported by a few immunohistochemical markers that help indicate their prognosis. However, new additional tests would be highly useful. The purpose of this study was to develop such a test using fractal analysis which is increasingly being applied in science, especially in the field of biomedicine. A total of 53 circumanal gland tumors were chosen from our department archives. After a precise histological classification according to the World Health Organization classification, the number of de novo classified samples was as follows: 15 adenomas, 11 epitheliomas, 21 well differentiated carcinomas, 6 poorly differentiated carcinomas. Ten samples of normal circumanal gland were also included as control. All samples were immunohistochemicaly stained with vimentin. All immunohistochemical reactions were photographed at two different magnifications -100X and 400X- and converted to 1 bit in black and white (bitmap) images, thus enhancing the positive vimentin reactions. These images were used for the assessment of fractal dimension applying the box counting method and computer software Fractalyse. To determine the significance of results, conventional statistics were performed using Statistica software.

The overall vimentin stain score was significantly higher in epitheliomas and carcinomas than in normal circumanal glands (CG) or adenomas. Mean values of fractal dimension estimated at magnification 100X and 400X were as follows: normal CG 1.318 and 1.372, CG adenomas 1.384 and 1.408, CG epitheliomas 1.547 and 1.597, CG well differentiated carcinomas 1.569 and 1.607, CG poorly differentiated carcinomas 1.679 and 1.723. Significant differences (at level of 5%) of these values were observed between individual groups of CG adenomas or normal CG, and epitheliomas or carcinomas.

The above results indicate vimentin immunohistochemistry staining and assessment of fractal dimension as an ancillary diagnostic method of choice when discerning between benign and malignant tumors of circumanal glands. Additional development of the method of fractal dimension assessment may yield a possibility for this tool to successfully discern between all of the types of CG tumors.

Sessile serrated adenoma (SSA) vs. traditional serrated adenoma (TSA)

The morphologic distinction between various serrated polyps of the colorectum may be challenging. The distinction between sessile serrated adenoma (SSA) and traditional serrated adenoma (TSA) may be difficult using currently available criteria mostly based on cytologic characteristics. We have evaluated 66 serrated polyps including 29 SSA, 18 TSA, and 19 hyperplastic polyps for overall shape of the polyps, architectural features of individual crypts, the presence of eosinophilic cytoplasm, size and distribution of the proliferation and maturation zones, as well as Ki-67 and CK20 expression. The extent of the expression of CK20 and Ki-67 could not distinguish between the 3 types of serrated polyps, but the distribution of their expression was very helpful and differences were statistically significant. The distribution of Ki-67+ cells was the single most helpful distinguishing feature of the serrated polyp type (P<0.0001, chi test). Hyperplastic polyps had regular, symmetric, and increased Ki-67 expression. SSA had irregular, asymmetric, and highly variable expression of Ki-67. TSA had low Ki-67 expression, which was limited to "ectopic crypts" and admixed tubular adenomalike areas. In serrated polyps, ectopic crypt formation (ECF) defined by the presence of ectopic crypts with their bases not seated adjacent to the muscularis mucosae was nearly exclusive to TSA and was found in all cases, while the presence of cytologic atypia and eosinophilia of the cytoplasm were characteristic, but not limited to TSA. No evidence of ECF, but nevertheless abnormal distribution of proliferation zone was characteristic of SSA, whereas HP had neither. The presence of the ECF defines TSA in a more rigorous fashion than previous diagnostic criteria and also explains the biologic basis of exuberant protuberant growth associated with TSA and the lack of such growth in SSA. Recognition of this phenomenon may also help in exploring the genetic and molecular basis for differences between SSA and TSA, because these architectural abnormalities may well be a reflection of abnormalities in genetically programmed mucosal development.

Serrated mucosal lesions of the colorectum

PURPOSE OF REVIEW

To examine and clarify the nomenclature and histologic lesions identified as serrated mucosal lesions of the colorectum, including serrated adenomas, sessile serrated polyps (also known as sessile serrated adenomas) and hyperplastic polyps. This is timely given the significant confusion in ascribing a microscopic diagnosis and clinical utility of such a diagnosis.

RECENT FINDINGS

The emergence of sessile serrated polyps (or adenomas) as distinct histomorphologic lesions from serrated adenomas, as well as the appreciation of the possibility of different modes of dysplasia exhibited in serrated lesions.

SUMMARY

Clarification of the microscopic features, nomenclature and biology of serrated lesions are important for accurate histologic diagnosis, and in clinical terms for useful outcomes assessment, recommendations for follow-up and risk stratification.

Clinicopathologic and endoscopic features of colorectal serrated adenoma: differences between polypoid and superficial types

BACKGROUND

Serrated adenoma is a distinct histologic colorectal lesion. There are two macroscopic types: polypoid and superficial. The aim of this study was to clarify clinicopathologic and endoscopic differences between polypoid and superficial serrated adenomas.

METHODS

An analysis was conducted of the clinicopathologic and endoscopic features for 240 polypoid and 127 superficial serrated adenomas examined by colonoscopy, and the surface pit patterns of 114 polypoid and 64 superficial serrated adenomas examined by magnifying videoendoscopy.

RESULTS

The male:female gender ratio for the polypoid serrated adenomas (3.5:1) was significantly higher than that for the superficial serrated adenomas (1.7:1). Superficial serrated adenomas were significantly larger than polypoid serrated adenomas (mean [standard deviation], respectively, 10.1 [7.9] mm vs. 6.3 [4.6] mm). In the distal segments of the colorectum, polypoid serrated adenomas were more common than superficial serrated adenomas. Granulonodular and lobular appearances at endoscopy were significantly more common for polypoid (23.3%) than for superficial serrated adenomas (7.1%). Pit patterns differed between the lesion types: polypoid serrated adenomas had type III(L) or IV pit patterns; all superficial serrated adenomas had the type II pit pattern. The relative frequency of occurrence of high-grade dysplasia and carcinoma in situ among superficial serrated adenomas (25.2%) was significantly greater than that among polypoid serrated adenomas (9.2%). The tubulovillous growth pattern was significantly more common in polypoid tumors (31.5%) than in superficial tumors (0%).

CONCLUSIONS

Polypoid and superficial serrated adenomas have different clinicopathologic characteristics and growth patterns.

Colorectal polyps and other precursor lesions. Need for an expanded view

The traditional understanding of adenomas serving as precursors for a homogeneous group of adenocarcinomas is being assailed from all sides. Clearly, the relationship between precursor lesions and adenocarcinomas with defective DNA mismatch repair is much more complex and appears to include right-sided hyperplastic polyps as precursor lesions in some cases. Additional data will be forthcoming regarding this risk of adenocarcinoma development in right-sided hyperplastic polyps, both through defective DNA mismatch repair and methylation of the MGMT gene. This will likely be accompanied by an attempt to reclassify at least some larger hyperplastic polyps as serrated adenomas either on subtle morphologic or molecular grounds.