Summary
Aims: By immunocytochemical staining for lymphatic vessels using anti-lymphatic vessel hyaluronan receptor (LYVE-1) antibody, pancreatic islets and some pancreatic endocrine tumours (PETs) were positively stained for the cytoplasm in addition to lymphatic vessels. The current study was extended to investigate possible immunostaining of gastrointestinal carcinoids using goat antihuman LYVE-1 antibody.
Methods: Lymphatic vessels were immunostained by LYVE-1 and blood vessels were immunostained by factor 8 (F-8).
Results: Among 27 gastrointestinal carcinoids, six cases (22%) including five primary and one metastatic carcinoids were positive in the cytoplasm for LYVE-1 in addition to lymphatic vessels and there were abundant lymphatic and blood vessels at the margin of the carcinoids. These six LYVE-1 positive cases consisted of three of 10 small intestinal, one of five appendiceal and two of seven large intestinal carcinoids. There was no LYVE-1 positive staining in the adjacent normal gastro-intestinal mucosa.
Conclusions: The presence of LYVE-1 immunostaining in some gastrointestinal carcinoids may support a structure-function relationship of lymphatic vessels/hyaluronan receptor for modulating synthesis and secretion of hormones and amines by carcinoid tumour cells.