c d
Figure 4. A low power field H&E staining revealed a fibroconnective
tissue containing inflammatory cells infiltration, composed mostly
lymphoplasmacytic admixed with polymorphonuclears (PMNs) and foci of
necrosis(a); also, in the HPF(*400), lymphoplasmacytic infiltration was
seen (b). Immunohistochemistry showed approximately 60 IgG+ plasma cells
(c), of which almost more than 40 of the IgG+ plasma cells were
IgG4+(d).(IgG+/IgG4+>40%)