Introduction: IgG4-related disease (IgG-4-RD) is a chronic fibro-inflammatory condition that is characterized by tumor-like swelling of the involved organs and the presence of polyclonal IgG4- positive plasma cell-enriched infiltrates within various organs. Deposition of these infiltrates along with fibrosis can result in organ dysfunction or obstructive or compressive complications from mass effect. Because of its varied clinical presentation, IgG-4-RD can mimic malignancy and autoimmune conditions thus a thorough history, physical examination, and diagnostic studies, including histopathology of the biopsied lesion, should be pursued to aid in the diagnosis.

Case Presentation: A 29-year-old woman presented with complaints of intermittent abdominal pain of 8 years duration. The pain was described as waxing and waning, located in the left upper and lower quadrants. The patient was evaluated on several occasions in the ED (Emergency Department) department as well as outpatient setting. Workup included normal liver function tests, mild microcytic anemia, normal metabolic panel, normal colonoscopy, and EGD. Abdominal CT and US which were significant for a left adrenal “cyst” measuring 3.7 cm. Over the span of 8 years, the patient had other manifestations including urticarial rash, persistent left parotid gland swelling, and weight loss due to recurrent abdominal pain. She denied any constitutional symptoms, sicca symptoms, eye manifestations, shortness of breath, or joint pain. Because of persistent abdominal pain of unclear etiology, the patient had a repeat CT scan which showed a necrotic adrenal mass measuring 5 x 6 cm. The patient subsequently underwent laparotomy with findings of an extensive mass obliterating the left kidney, spleen, and tail of the pancreas resulting in partial pancreatectomy, left nephrectomy, and adrenalectomy along with splenectomy.

Diagnosis: Pathology results showed spindle cell lesion with storiform architecture and prominent lymphoplasmacytic infiltrate with reactive follicles. The infiltrate was T-cell, and the lymphoid follicles were predominantly B cells. There were abundant IgG and IgG 4 positive plasma cells with up to 70% IgG4 expressing plasma cells and with the IgG4/IgG ratio of 60% which confirmed the diagnosis of IgG-4- RD. Extensive work-up for other auto-immune diseases was negative.

Outcome: After surgery, the patient became pregnant and remained pain-free but continued to have intermittent pruritic rash and arthralgias. Immunoglobulin levels remained normal without the use of systemic steroids.

References and Resources:

1. Kurowecki, Darya et al. “Cross-Sectional Pictorial Review of IgG4-Related Disease.” British journal of radiology 92.1103 (2019): 20190448–20190448. Web.
2. Al-Khalili OM, Erickson AR. IgG-4 Related Disease: An Introduction. Mo Med. 2018;115(3):253-256.
3. Perugino, C.A., Stone, J.H. IgG4-related disease: an update on pathophysiology and implications for clinical care. Nat Rev Rheumatol 16, 702–714 (2020). https://doi.org/10.1038/s41584-020-0500-7
4. Wallace ZS, Naden RP, Chari S Members of the ACR/EULAR IgG4-RD Classification Criteria Working Group, et alThe 2019 American College of Rheumatology/European League Against Rheumatism classification criteria for IgG4-related diseaseAnnals of the Rheumatic Diseases 2020;79:77-87.