A 47-Year-Old Woman with Immunoglobulin G4 (IgG4)-Related Disease Involving the Right Ovary

Abstract

BACKGROUND Immunoglobulin G4 (IgG4)-related disease is immune-mediated and was first proposed as a defined entity after studies on patients with autoimmune pancreatitis. Since then, it has been reported in many organs. Involvement of the ovaries is rare, and to our knowledge, only 2 cases have been reported in the literature. IgG4-related disease is associated with increased serum IgG4 levels. Organ involvement includes a lymphoplasmacytic infiltrate, fibrosis, and obliterative phlebitis, with immunohistochemistry showing IgG4-positive plasma cells. This report is of a case of IgG4-related disease involving the right ovary. CASE REPORT A 47-year-old woman presented with a right ovarian cyst. An ultrasound scan revealed a complex right ovarian cyst with multiple septations. The hormonal profile and tumor markers were unremarkable. Gross examination showed fragments of cyst wall. Histologic examination revealed a follicular cyst, surrounded by a dense lymphoplasmacytic infiltrate rich in eosinophils, partially obliterative phlebitis, and fibrosis. Immunohistochemically, IgG marked most of the plasma cells, of which 70% expressed IgG4, with a count >50 cells per high-power field. Subsequent testing of serum IgG4 showed that the level was elevated (330 mg/dL). A diagnosis of IgG4-related disease was made. CONCLUSIONS Ovarian involvement by IgG4-related disease is rarely described in the literature. Our patient is likely to be the third case. We believe that cumulative findings from our case along with the 2 already reported cases increase awareness and may establish a framework for building more objective criteria to define this entity in the ovaries, similar to what has been achieved in some other organs.

Figure 1.

Main histologic features (hematoxylin and eosin staining). (A) Diffuse lymphoplasmacytic inflammatory cell infiltrate in the ovary with areas of fibrosis (original magnification 100×). The infiltrate is angiocentric, as is apparent in the 2 vessels shown. (B) Original magnification 100×. In a high-power view, the infiltrate appears rich in plasma cells and eosinophils and there is accentuation around veins with involvement of the wall (phlebitis) and extension into the lumen with obliteration. (C, D) Original magnification 400×.

Figure 2.

Immunohistochemical characteristics of the plasma cell infiltrate. (A) A CD138 marker highlights the prominent plasma cell component of the inflammatory infiltrate (original magnification 100×). (B) Most of the plasma cells show expression of immunoglobulin G (IgG) (original magnification 200×). (C) An IgG4 marker shows that more than 70% of the IgG-positive plasma cells express IgG4 (original magnification 200×). (D) In a high-power view, the number of plasma cells expressing IgG4 is in excess of 50 cells per high-power field (original magnification 400×). The findings in C and D reflect an increased number of IgG4-positive plasma cells beyond the cut-off value for the diagnosis of IgG4-related disease.