IgG4-associated conditions Diagnosis of IgG4 disease is depending on BIOPSY. While IgG4 levels can be informative (and absolutely should be checked!), you really need to see pathology with the classic lymphoplasmacytic tissue inflammation of IgG4-positive plasma cells and lymphocytes with accompanying storiform fibrosis. Even the pathology, however, can at times be nonspecific, looking quite similar to other conditions such as some malignancies, granulomatosis with polyangiitis, and Castleman’s diseases to name a few. #IgG4 #conditions #diseases #differential #diagnosis
