Figure 1.

Histological features of TLOs (45) in chronic pancreatitis (A), IgG4-related lymphoplasmacytic sclerosing pancreatitis (autoimmune pancreatitis) (B,C), and pancreatic ductal adenocarcinoma (PDAC) (D,E). TLOs are distributed evenly in inflamed tissues (A,B) and sometimes concentrated near the target structure (around ducts) (C). In contrast, cancer tissue is surrounded by peritumoral TLOs (D) and a rare pancreatic cancer case has intratumoral TLOs (D). Common PDAC has a paucity of vessels and lacks intratumoral TLOs, although limited cases do have intratumoral TLOs that are richer in tumor-infiltrating lymphocytes and retain relatively intact vascular networks consisting of arterioles, venules, and capillaries without cancer invasion.