Parathyroid adenoma with prominent lymphocytic infiltrate having histological features highly suggestive of IgG4-related disease: a case report and literature review

IgG4-related disease presenting as severely symptomatic hypercalcemia: A case report and review of literature

Immunoglobulin G4-related disease (IgG4-RD)-associated hypercalcemia has rarely been reported. We report a case of IgG4-RD that presented as severe symptomatic hypercalcemia. A 50-year-old woman with a history of sustained bilateral periorbital swelling and proptosis for more than 5 years presented to our hospital complaining of a 3-day history of significant and progressive nausea, vomiting, loss of appetite, fatigue, and pruritus. She denied a long history of medication. On admission, laboratory tests showed severe hypercalcemia with serum adjusted calcium elevated to 4.34 mmol/L and renal dysfunction with serum creatinine elevated to 206 μmol/L. Urinary calcium excretion was increased. The serum IgG4 subclass was markedly elevated to 22.4 g/L with polyclonal hypergammaglobulinemia. Tests of autoantibodies were all negative. Bone metabolism markers that reflect the activity of osteoblasts and osteoclasts were all significantly elevated. However, the levels of intact parathyroid hormone and 25(OH) vitamin D3 were decreased. B-ultrasonography showed chronic inflammation of bilateral submandibular glands. Neither bone marrow biopsy nor positron emission tomography - computed tomography examination showed evidence of neoplastic diseases. The patient was treated with intravenous saline infusion, loop diuretics, salmon calcitonin, glucocorticoids, and hemodialysis with a good response.

Hypercalcemia in IgG4-related disease: coincidental or associated? Case based review

Immunoglobulin (Ig) G4-related disease (IgG4RD) is a chronic autoimmune disorder characterized by dense lymphoplasmacytic infiltrations and fibrosis of storiform pattern. The most typical manifestations include major salivary or lacrimal gland involvement, autoimmune pancreatitis, and retroperitoneal fibrosis. While the increase in IgG4 is the typical feature of the disease, hypercalcemia has been rarely reported in IgG4RD so far, only one of these cases has been shown parathyroid gland involvement (isolated involvement). In this study, we present a 43-year-old female patient with weight loss, pancreatic mass, lymphadenopathy, nodular lesion in the lung, hypercalcemia, and also increased level of serum IgG4. Histopathological investigation following parathyroidectomy revealed a dense lymphoplasmacytic infiltrate with an IgG4 to IgG ratio of > 50% in the fat tissue surrounding the parathyroid gland, particularly at the perivascular areas. This is the first systemic IgG4RD case in combination with hypercalcemia in the literature who was detected to have parathyroid adenoma. Our aim in this review is to emphasize that, although rarely, IgG4RD may be accompanied by hypercalcemia and parathyroid gland may be one of its target sites.