IgG4-related disease mimicking gynecologic malignancy

Area of Science:

• Gynecologic Oncology
• Immunology
• Pathology

Background:

• Immunoglobulin G4 (IgG4) related disease is a systemic condition characterized by fibrosis and IgG4-positive plasma cell infiltration.
• Gynecologic organ involvement is rare, making diagnosis challenging.
• Distinguishing IgG4-related disease from malignancy is critical due to differing treatment protocols.

Observation:

• Two cases of IgG4-related disease presenting as gynecologic malignancy mimics are described.
• Case 1: An 85-year-old woman with a uterine mass and lymphadenopathy, initially concerning for malignancy.
• Case 2: A 35-year-old woman with FDG-avid lymphadenopathy mimicking cervical cancer recurrence.

Findings:

• Biopsies in Case 1 revealed IgG4-positive plasma cells, leading to rituximab treatment.
• Biopsies in Case 2 showed lymphoid hyperplasia with increased IgG4 plasma cells, not carcinoma, after extensive workup.
• Both patients showed improvement with appropriate IgG4-related disease treatment (rituximab or steroids).

Implications:

• IgG4-related disease should be considered in the differential diagnosis of primary or recurrent gynecologic malignancies.
• Positron emission tomography (PET) imaging can reveal FDG-avid lesions in IgG4-related disease, mimicking cancer.
• Accurate diagnosis of IgG4-related disease is essential for effective treatment and avoiding unnecessary oncologic interventions.