Computer-assisted morphometric analysis of lymphatic vessel changes in hamster tongue carcinogenesis

Background: To characterize lymphangiogenesis in early-stage hamster tongue carcinoma development, morphological features and spatial relationships of lymphatic vessels. Methods: Lymphatic vessels were examined histochemically, using 5'-Nase-ALPase enzyme and combined light and electron microscopy to measure lymphatic vessel area (LVA) and lymphatic vessel density (LVD). Results: In atypical hyperplastic tissues, LVA was found to be 1429.97 and LVD was found to be 39, in carcinoma in situ LVA was 2538.33 and LVD was 48, and in micro-invasive carcinoma LVA was 5733.74 and LVD was 59. Increased lymphangiogenesis was seen in pre-neoplastic states and in early-stage oral squamous cell carcinoma (OSCC). Small regular lymphatic vessels predominated in atypical hyperplasia, and large, irregular lymphatic vessels in early-stage OSCC. Lymphatic endothelial vessels were stretched and porous over large areas. Conclusions: Newly formed lymphatics and patulous intercellular junctions may be optimally suited for tumor cell metastasis through lymphatic channels in early- and middle-phase carcinogenesis. Lymphatic capillary LVA and LVD became enlarged, and positively correlated, with malignancy, but show no correlation with 7,12-dimethylbenz[a]anthracene-induced time.