Immunocytochemical staining for lymphatic and blood vessels with frozen sections: using LYVE-1 for lymphatic vessel and von Willebrand factor for blood vessel marker.

Almost all human tissues are supplied with lymphatic vessels, yet histological structure and function of lymphatic vessels is still elusive. Most immunocytochemical studies have been performed with the routinely formalin-fixed and paraffin-embedded tissue. This study aimed to investigate lymphatic and blood vessels immunocytochemically with frozen sections to explore the masked lymphatic and blood vessels in the routinely processed normal tissues. Several normal monkey tissues were frozen in liquid propane, and frozen sections were immunostained for lymphatic and blood vessels using LYVE-1 for lymphatic vessels and von Willebrand factor for blood vessels. In the liver, sinusoids were immunostained panlobularlly for LYVE-1 compared to LYVE-1 immunostaining limited in the pericentral lobe with the routinely processed liver. In the Jejunal villi, lacteals were surrounded by scattered mall venous capillaries. In the large intestines, a few longitudinal lymphatic vessels were detected in lamina propria. Pancreatic islets were surrounded by baskets of rich venous capillaries. Glomerular capillaries were diffusely positive for von Willebrand factor, suggesting leaking capillaries for von Willebrand factor. Prostate had scattered lymphatic and numerous blood vessels in the stroma with nerve bundles in the fibrous capsule. Many lymphatic and blood vessels were immunostained only in frozen sections, which were not immunostained in the routinely processed tissues. Routine processing masks antigen sites of lymphatic and blood vessels. Therefore, immunocytochemical staining with frozen sections is superior to routinely embedded tissues and this immunostaining would further add histopathological information on tumor spread and liver and kidney biopsies.