Validation of digital pathology imaging for primary histopathological diagnosis.

AIMS: Digital pathology (DP) offers advantages over glass slide microscopy (GS), but data demonstrating a statistically valid equivalent (i.e. non-inferior) performance of DP against GS are required to permit its use in diagnosis. The aim of this study is to provide evidence of non-inferiority. METHODS AND RESULTS: Seventeen pathologists re-reported 3017 cases by DP. Of these, 1009 were re-reported by the same pathologist, and 2008 by a different pathologist. Re-examination of 10 138 scanned slides (2.22 terabytes) produced 72 variances between GS and DP reports, including 21 clinically significant variances. Ground truth lay with GS in 12 cases and with DP in nine cases. These results are within the 95% confidence interval for existing intraobserver and interobserver variability, proving that DP is non-inferior to GS. In three cases, the digital platform was deemed to be responsible for the variance, including a gastric biopsy, where Helicobacter pylori only became visible on slides scanned at the ×60 setting, and a bronchial biopsy and penile biopsy, where dysplasia was reported on DP but was not present on GS. CONCLUSIONS: This is one of the largest studies proving that DP is equivalent to GS for the diagnosis of histopathology specimens. Error rates are similar in both platforms, although some problems e.g. detection of bacteria, are predictable.

The binary oral dysplasia grading system: validity testing and suggested improvement.

OBJECTIVES: A binary system is reputed to be superior to the World Health Organization (WHO) system in grading oral dysplasia. We aimed to validate its reproducibility and prognostic ability and examine whether it could be improved. STUDY DESIGN: Three pathologists graded 141 oral epithelial dysplasia biopsies with the use of both systems. Observer variability and prognostic ability were assessed with the use of kappa and logistic regression models. RESULTS: The binary system showed superior agreement to the WHO system (multirater kappa 0.59 vs. 0.49, respectively) but similar prognostic ability (odds ratio [OR] 4.59 [P = .014] vs. OR 2.25 [P = .02], respectively). Adding smoking and alcohol slightly improved the prognostic ability of both systems (OR 5.10 vs. OR 2.42, respectively). Our new binary system with a refined diagnostic threshold demonstrated a slightly greater prognostic ability and improved ability to differentiate between high- and low-risk moderate dysplasia cases. CONCLUSIONS: The binary system has similar prognostic ability but superior reproducibility compared with the WHO system. Prognostication is improved still further by using a new threshold.

Carcinoid syndrome from small bowel endocrine carcinoma in the absence of hepatic metastasis.

An 80-year-old male patient presented with abdominal pain, paroxysmal diaphoresis, diarrhoea and vomiting. CT scan revealed a small bowel endocrine carcinoma (or 'carcinoid' tumour), but the absence of hepatic disease. The lesion was excised 'en-bloc'. Intra-operatively, there was wide fluctuation in blood pressure associated with tumour manipulation, with hyper- and hypotension. Carcinoid syndrome usually occurs from gastrointestinal tumours when hepatic metastases occur, causing flushing, diarrhoea, bronchoconstriction and murmurs from cardiac valvular lesions. This patient did not have radiological evidence of hepatic metastasis, but the syndrome could still occur with midgut tumours via local invasion of the retroperitoneal circulation, or by action of substances other than serotonin that do not undergo hepatic metabolism.