A 54-year old man was referred in 2010 to our outpatient clinic with a 4-year history of dry mouth and eyes and diffuse arthralgias. Review of symptoms was essentially negative. Past medical history was unremarkable except for a longstanding allergic rhinitis. Family history was insignificant. On physical examination a dry, red, deep fissured tongue and bilaterally swollen parotid and submandibular glands were noted. No other abnormalities were revealed. Shirmer's I test was abnormal (<5mm/5min) in both eyes and Rose Bengal staining was positive with a score of 4/9. Complete blood count, serum chemistry and lipid profile were within normal limits. Immunological screening revealed positive antinuclear antibody (1/320, fine speckled) and rheumatoid factor (60U/ml, cut-off value: 20U/ml) as well as low C4 serum levels (10mg/dl). Anti-Ro/SSA and anti-La/SSB antibodies were negative. Serum cryoglobulins or paraproteins were not detected. Antibodies against HIV and HCV were also negative. Chest X-ray (CXR) to rule out sarcoidosis was normal. Labial minor salivary gland biopsy revealed periductal lymphocytic infiltrates (focus score: 2.5) without monoclonal lymphocytic population, compatible with the diagnosis of Sjögren's syndrome (SS). He was initiated with pilocarpine hydrochloride 5mg tid and was followed up regularly every 6 months till 2012.
In March, 2012, he was admitted to our hospital because of abdominal pain irradiating to the back with associated nausea and vomiting. Physical examination disclosed firm bilateral parotid gland enlargement, dry, fissured, devoid of epithelium tongue and tenderness in the upper abdomen. Lung and heart examination were unrevealing. Laboratory tests were notable for an increased serum (230U/l) and urine amylase levels (500U/l). Autoantibody profile and serum complement levels were as previously described. CXR was normal, while abdomen CT scan showed diffuse enlargement of the pancreas with a capsule-like low-density rim and the presence of periaortic soft tissue mantle in the abdominal aorta. Serum IgG4 levels were 316 mg/dl. Labial minor salivary gland biopsy was reevaluated and stained for κ:λ ratio as well as IgG(+) and IgG4 (+) plasmacytes. Mean number of IgG4 (+) plasmacytes was 30/hpf and IgG4 (+)/IgG(+) was > than 40% while κ/λ positive B lymphocytes was not greater than 2/1. On the basis of the newly established criteria, the diagnosis of IgG4-related disease (IgG4-RD) was undertaken.
Differential diagnosis of sicca syndrome in a man is quiet extensive including autoimmune (SS, IgG4-RD, sarcoidosis), infectious (HIV and HCV, HTLV-1) and metabolic (diabetes mellitus, lipoproteinemias) conditions, neoplastic/infiltrative disorders (lymphoma, tumors, amyloidosis), drug side effects (anticholinergic and antidepressant), and head and neck irradiation. Detailed medical history, physical examination, laboratory and radiological studies and the performance of a minor labial salivary gland biopsy will aid at the establishment of a correct diagnosis.
IgG4-RD is a newly described clinical entity, affecting mainly middle-aged men, characterized by increased IgG4 serum levels and by infiltrates of IgG4 (+) plasmacytes, obliterative phlebitis and fibrosis of the affected tissues. IgG4-related sialadenitis, previously called Mikulicz disease, is a mimicker of SS, since they share a lot of clinical (sicca symptoms, salivary gland enlargement, arthralgias) and serological (presence of ANA and rheumatoid factor, low serum complement levels) manifestations. The correct diagnosis is of paramount importance, since these patients usually respond to corticosteroid therapy.
Disclosure of Interest None declared