Cory Perugino, rheumatologist and IgG4-RD researcher at Mass General, explains why the disease is so often misdiagnosed and how greater awareness can improve outcomes.
Transcript
IgG4-related disease is a difficult diagnosis to make for multiple reasons. One reason is how recently the disease has been described and defined. It wasn’t labeled in a unifying way until 2003.
So, even though the disease has likely been around for centuries, it’s relatively new to medical literature and to doctors’ knowledge bases.
As a result, it’s often missed simply due to a lack of awareness. Many radiologists, pathologists, and other specialists may not be familiar with it. It’s not routinely taught in medical school, and with so many diseases to cover in a limited time, rare diseases like IgG4-related disease are often excluded from the curriculum.
These are the kinds of conditions that doctors typically learn about during specialized training, particularly in rheumatology and related fields.
When it comes to common misdiagnoses, cancer or some type of malignancy is probably the most frequent. That’s because IgG4-related disease often presents with enlarged organs or tumor-like masses that can look very similar to cancer on imaging.
It’s usually assumed to be cancer until a biopsy shows otherwise—specifically, the absence of malignant cells under the microscope.
Other common misdiagnoses include autoimmune or rheumatologic diseases such as sarcoidosis or vasculitis. These conditions share overlapping symptoms and imaging findings, which can make it even harder to identify IgG4-related disease correctly.
