Background/Aims: A white substance that is opaque to endoscopic light is sometimes observed in the epithelium during narrowband imaging with magnifying endoscopy of gastric or colorectal epithelial neoplasms. This prospective observational study aimed to determine whether the morphology of the white opaque substance (WOS) allows differential diagnosis between colorectal adenoma and carcinoma. Methods: A consecutive series of patients with colorectal adenomas or early carcinomas who underwent endoscopic resection or surgical excision were studied. The morphology of the WOS was determined based on endoscopic images before the histopathological diagnosis was performed. The primary outcome was the diagnostic performance of an irregular WOS as a marker of colorectal carcinoma. Results: The study analyzed 125 lesions. A total of 33 lesions showed an irregular WOS, and 92 lesions showed a regular WOS. Among the 33 lesions found to show an irregular WOS, 30 were carcinomas. Among the 92 lesions showing a regular WOS, 79 were adenomas. With irregular WOS as a marker of carcinoma, the diagnostic accuracy was 87%, sensitivity was 91%, and specificity was 86%. Conclusions This study demonstrated the potential usefulness of the morphology of the WOS as a marker for the differential diagnosis between adenoma and carcinoma in cases of colorectal epithelial neoplasms.

Background/Aims: A white substance that is opaque to endoscopic light is sometimes observed in the epithelium during narrowband imaging with magnifying endoscopy of gastric or colorectal epithelial neoplasms. This prospective observational study aimed to determine whether the morphology of the white opaque substance (WOS) allows differential diagnosis between colorectal adenoma and carcinoma. Methods: A consecutive series of patients with colorectal adenomas or early carcinomas who underwent endoscopic resection or surgical excision were studied. The morphology of the WOS was determined based on endoscopic images before the histopathological diagnosis was performed. The primary outcome was the diagnostic performance of an irregular WOS as a marker of colorectal carcinoma. Results: The study analyzed 125 lesions. A total of 33 lesions showed an irregular WOS, and 92 lesions showed a regular WOS. Among the 33 lesions found to show an irregular WOS, 30 were carcinomas. Among the 92 lesions showing a regular WOS, 79 were adenomas. With irregular WOS as a marker of carcinoma, the diagnostic accuracy was 87%, sensitivity was 91%, and specificity was 86%. Conclusions This study demonstrated the potential usefulness of the morphology of the WOS as a marker for the differential diagnosis between adenoma and carcinoma in cases of colorectal epithelial neoplasms.

Objective: To determine the effect of extracts from Phyllanthus acidus (P. acidus) (L.) Skeels and Rhinacanthus nasutus (R. nasutus) (L.) Kurz leaves on melanogenesis and the underlying mechanism in normal human epidermal melanocytes (NHEM) and a reconstitutive skin model. Methods: NHEM and a reconstitutive skin model were stimulated with ethanol extracts of P. acidus (L.) Skeels and R. nasutus (L.) Kurz leaves. mRNA expression of microphthalmia-associated transcription factor (MITF), tyrosinase (TYR), tyrosinase-related protein 1 (TYRP1) and dopachrome tautomerase (DCT) were examined by real-time PCR. The melanin content in NHEM was also measured. Moreover, protein levels of tyrosinase were determined using western blot analysis. Results: In NHEM and the reconstitutive skin model, ethanol extracts from P. acidus (at 12.5 and 25.0 μg/mL) and R. nasutus (at 6.25 and 12.50 μg/mL) significantly diminished mRNA expression of MITF, TYR, TYRP1 and DCT in a concentration-dependent manner. P. acidus and R. nasutus extracts also reduced the amount of melanin in α-MSH-stimulated NHEM. Moreover, P. acidus and R. nasutus extracts markedly suppressed tyrosinase at the translational level in the reconstitutive skin model. Conclusions: P. acidus and R. nasutus extracts significantly reduced melanogenesis in NHEM and the reconstitutive skin model, suggesting that P. acidus and R. nasutus extracts can inhibit melanin synthesis through downregulation of MITF, TYR, TYRP1 and DCT. Therefore, the ethanol extracts of P. acidus and R. nasutus contain compounds that have the potential for development as a skin lightening agent for the treatment of hyperpigmentation disorder or melasma.