Fig. 4

With standard forceps, a minimal amount of specimen is obtained (a, 2× object lens magnification, a total of 4 biopsies, 2.4mm²). In contrast, using a cryoprobe yields a sufficient amount of specimen for a definitive diagnosis (b, 2× object lens magnification, a total of 10 biopsies, 93.0mm²). Hematoxylin and eosin stained tissues show several invasive lymphocytes and plasma cells in the mucosa along with active fibrosis in a part of it (10× object lens magnification) (c). On IgG (d) and IgG4 (e) immunopathological staining, numerous positive plasma cells are visible with no difference among them. We detected > 10 IgG4 positive plasma cells per high power field and the IgG4 positive/IgG positive cell ratio was above 40% in every five areas