[Clinicopathologic evaluation on colorectal laterally spreading tumor (LST)]

Area of Science:

• Gastroenterology and Oncology
• Gastrointestinal Pathology
• Endoscopic Resection

Context:

• Colorectal laterally spreading tumors (LST) are a distinct entity requiring careful characterization.
• Macroscopic classification of LST into granular (G) and flat (F) types is crucial for understanding their behavior.
• Previous studies have highlighted differences, but a detailed clinicopathologic comparison is warranted.

Purpose:

• To compare the clinicopathologic characteristics of granular type (G type) and flat type (F type) colorectal laterally spreading tumors (LST).
• To evaluate the malignant potential and precursor role of different LST subtypes in colorectal carcinoma development.

Summary:

• This study analyzed 92 colorectal LSTs, classifying them as G type (47) or F type (45).
• F type LSTs were significantly smaller than G type LSTs but exhibited a higher incidence of carcinoma, submucosal invasion, and severe atypia.
• Carcinoma incidence in F type LSTs was higher across all size categories compared to G type LSTs, with no F type lesions showing a tubulo-villous adenoma component.

Impact:

• The findings reveal distinct clinicopathologic differences between F type and G type LSTs.
• F type LSTs demonstrate a higher malignant potential, suggesting a more significant role as a precursor to colorectal cancer.
• This distinction has implications for endoscopic surveillance, risk stratification, and treatment strategies for LSTs.