Epithelial misplacement in the muscularis propria after biopsy of a colonic adenoma

Diagnosis of T1 colorectal cancer in pedunculated polyps in daily clinical practice: a multicenter study

T1 colorectal cancer can be mimicked by pseudo-invasion in pedunculated polyps. British guidelines are currently one of the few which recommend diagnostic confirmation of T1 colorectal cancer by a second pathologist. The aim of this study was to provide insights into the accuracy of histological diagnosis of pedunculated T1 colorectal cancer in daily clinical practice. A sample of 128 cases diagnosed as pedunculated T1 colorectal cancer between 2000 and 2014 from 10 Dutch hospitals was selected for histological review. Firstly, two Dutch expert gastrointestinal pathologists reviewed all hematoxylin-eosin stained slides. In 20 cases the diagnosis T1 colorectal cancer was not confirmed (20/128; 16%). The discordant cases were subsequently discussed with a third Dutch gastrointestinal pathologist and a consensus diagnosis was agreed. The revised diagnoses were pseudo-invasion in 10 cases (10/128; 8%), high-grade dysplasia in 4 cases (4/128; 3%), and equivocal in 6 cases (6/128; 5%). To further validate the consensus diagnosis, the discordant cases were reviewed by an independent expert pathologist from the United Kingdom. A total of 39 cases were reviewed blindly including the 20 cases with a revised diagnosis and 19 control cases where the Dutch expert panel agreed with the original reporting pathologists diagnosis. In 19 of the 20 cases with a revised diagnosis the British pathologist agreed that T1 colorectal cancer could not be confirmed. Additionally, amongst the 19 control cases the British pathologist was unable to confirm T1 colorectal cancer in a further 4 cases and was equivocal in 3 cases. In conclusion, both generalist and expert pathologists experience diagnostic difficulty distinguishing pseudo-invasion and high-grade dysplasia from T1 colorectal cancer. In order to prevent overtreatment, review of the histology of pedunculated T1 colorectal cancers by a second pathologist should be considered with discussion of these cases at a multidisciplinary meeting.

High-resolution microendoscopy in differentiating neoplastic from non-neoplastic colorectal polyps

Colorectal cancer is one of the leading causes of death worldwide. The progression from adenoma to cancer is a well known phenomenon. Current clinical practice favors colonoscopy as the preferred modality for colorectal cancer screening. Many novel endoscopic technologies are emerging for the purposes of performing "optical biopsy" to allow real-time histologic diagnosis of polyps. High resolution microendoscopy is a low-cost endoscopic technology that has demonstrated high sensitivity and specificity in differentiating neoplastic and non-neoplastic polyps. With the ability to make real-time conclusions based on the endoscopic appearance of polyps, it is becoming increasingly possible to decrease the rate of unnecessary polypectomies and utilize a "resect and discard" strategy to decrease costs of pathology evaluation. Future directions for this technology include surveillance of premalignant conditions such as inflammatory bowel disease. Moreover, the low cost and relative ease of use of this technology lends itself to widespread applicability.

Confocal laser endomicroscopy for the diagnosis of colorectal cancer in vivo

OBJECTIVE

To evaluate the feasibility and accuracy of confocal laser endomicroscopy (CLE) for the in vivo diagnosis of colorectal cancer (CRC) compared with conventional histology.

METHODS

Consecutive patients who had undergone CLE examination for screening or surveillance colonoscopy were recruited. Suspected malignant lesions and adjacent mucosal sites were first examined by confocal imaging and then biopsied specimens of these sites were obtained. The confocal images were independently interpreted by two endoscopists. The diagnosis made with CLE was compared with the conventional histological diagnosis in a prospective and blinded fashion.

RESULTS

In total, 71 patients with suspected malignant lesions were included in the study. A total of 74 lesions and 92 adjacent mucosal sites were observed. The sensitivity, specificity and accuracy of CLE in diagnosing CRC were 97.1%, 99.0% and 98.2% for endoscopist A, and 98.6%, 96.9% and 97.6% for endoscopist B, respectively. The interobserver agreement between the two endoscopists was excellent (κ = 0.950). The accuracy of diagnosing poorly differentiated CRC using CLE was 97.0% for endoscopist A and 95.6% for endoscopist B.

CONCLUSION

CLE has the potential to enable an immediate diagnosis of CRC and the degree of differentiation of CRC during ongoing endoscopy in vivo.