IgG4-related diseases are a group of immune-mediated diseases characterized by a lymphoplasmacytic infiltrate with a prevalence of IgG4-positive plasma cells, storiform fibrosis, obliterative phlebitis. Autoimmune pancreatitis, sialadenitis, dacryoadenitis and retroperitoneal fibrosis are the most frequent manifestations. IgG4-related sialadenitis usually affects submandibular glands and is very rare in children. We report here a case of an unexpected diagnosis of IgG4-related sialoadenitis in a boy previously diagnosed as affected by juvenile recurrent parotitis.
A six-year old boy presented to our centre with left parotid swelling about 4x3 cm, tender, soft in consistency, with the overlying skin red and warm. He had low-grade fever and a mild enlargement of left cervical lymph nodes. In the last two years he had five episodes of parotitis and a diagnosis of juvenile recurrent parotitis.. The general conditions were good, and the remainder of the physical examination was normal. At the ultrasonography left parotid was enlarged, inhomogeneous, with a colliquated intraparotid lymph node and no evidence of sialolithiasis. Laboratory tests were normal, except for an increase of white blood cells and positivity for IgM and IgG anti-VCA, with anti-EBNA e anti-EA I negative. The patient was treated with cephalosporins and azitromycin, but after 10 days the parotid became fluctuating and the patient underwent to drainage and biopsy of the gland. He was discharged after 3 days of observation, without any complications, and treated with a further course of cefpodoxime and betametasone, with a good clinical response.Investigations for aerobic and anaerobic bacteria, mycobacteria and Bartonella on the pus were negative. Histology showed marked fibrosis and histiocytic and lymphoplasmacellular infiltration. The plasma cells were polyclonal and mostly expressed IgG4 subclass immunoglobulins. The final diagnosis was chronic sclerosing sialadenitis IgG4-related in recurrent parotitis and recent EBV infection.
The interest of this case comes from the rarity of IgG4-related sialadenitis in children. It is not possible to argue with certainty that the previous episodes of parotitis were manifestations of a IgG4-related disease, due to the lack of histological data. Serum IgG4 in our patient were normal, as described in literature in 30% of cases.