P. Sobarun, A. Yung, D.Lamont, P. Emanuel
IgG4-related disease (IgG4-RD) is a recently deﬁned clinical syndrome characterized by inﬁltration of tissues by IgG4+ plasma cells.
We describe a 74-year-old man who developed a lump on
the medial aspect of his left arm at the insertion site of a
PICC line. His history was signiﬁcant for psoriasis, psoriatic
arthritis and ongoing prosthetic hip infection requiring long-term antibiotics. Excision revealed impressive
lymphoplasmacytic inﬁltration of mainly IgG4 + plasma
cells accompanying CD4+ lymphocytes and storiform ﬁbrosis.
His serum IgG and IgG4 were normal. To date he has no
other signs or symptoms of IgG4-RD or recurrence of the
lump.Tokura et al
1recently classiﬁed IgG4-related skin diseases
into 7 subtypes. These were divided into primary eruptions
and secondary eruptions without mass formation by plasma
High levels of circulating IgG4 are seen in up to
60–70% of patients. Biopsy of the affected organ reveals the
features seen in the case presented herein. In most cases
several organs such as the pancreas, salivary and lacrimal
glands are also involved. Oral glucocorticoids produce a
therapeutic response in most patients.