Features of proliferative vs fibrotic IgG4-RD
| . | Proliferative . | Fibrotic . |
|---|---|---|
| Clinical | Involvement of specific organs Symptoms are from tumefactive swelling of organs and organ dysfunction Chronic, relapsing and remitting | Involvement of body regions rather than distinct organs Contiguous spread and architectural distortion Progressive disease Chronic, long-standing disease (median time to diagnosis >6 months) |
| Organ involvement | Lacrimal and major salivary glands Lymph nodes Orbits and sinuses Lungs and airways Vasculature (aorta, coronary arteries) Pancreas and hepatobiliary system Kidneys | Retroperitoneum/aortitis Mediastinum Abdominal mesenteritis Thyroid Meninges |
| Laboratory | High serum IgG4 (especially Asian patients) Frequent elevation in IgE Eosinophilia Hypocomplementemia CRP and erythrocyte sedimentation rate are low or modestly elevated in most cases | Normal or slightly elevated serum IgG4 and IgE Normal complement CRP and erythrocyte sedimentation rate are low in most cases but elevated in the subset with active aortitis |
| Radiology | CT scan neck to pelvis sufficient for most If lacrimal swelling → CT head as well to assess for orbital involvement | For fibrotic disease, FDG-PET may be helpful to rule out histiocytosis (bone involvement) or lymphoma/metastatic cancer. FAPI-PET is an emerging tool for assessing fibrotic disease. |
| Pathology | Dense lymphoplasmacytic infiltrate with many IgG4+ plasma cells Scattered eosinophils Storiform fibrosis Obliterative phlebitis rare | Scant lymphoplasmacytic infiltrate with scattered IgG4+ plasma cells Storiform fibrosis predominant Obliterative phlebitis predominant |
| Treatment | Typically responsive to glucocorticoids and B-cell depletion | Glucocorticoids and B-cell depletion halt progression, but fibrosis is often not reversible. |
| . | Proliferative . | Fibrotic . |
|---|---|---|
| Clinical | Involvement of specific organs Symptoms are from tumefactive swelling of organs and organ dysfunction Chronic, relapsing and remitting | Involvement of body regions rather than distinct organs Contiguous spread and architectural distortion Progressive disease Chronic, long-standing disease (median time to diagnosis >6 months) |
| Organ involvement | Lacrimal and major salivary glands Lymph nodes Orbits and sinuses Lungs and airways Vasculature (aorta, coronary arteries) Pancreas and hepatobiliary system Kidneys | Retroperitoneum/aortitis Mediastinum Abdominal mesenteritis Thyroid Meninges |
| Laboratory | High serum IgG4 (especially Asian patients) Frequent elevation in IgE Eosinophilia Hypocomplementemia CRP and erythrocyte sedimentation rate are low or modestly elevated in most cases | Normal or slightly elevated serum IgG4 and IgE Normal complement CRP and erythrocyte sedimentation rate are low in most cases but elevated in the subset with active aortitis |
| Radiology | CT scan neck to pelvis sufficient for most If lacrimal swelling → CT head as well to assess for orbital involvement | For fibrotic disease, FDG-PET may be helpful to rule out histiocytosis (bone involvement) or lymphoma/metastatic cancer. FAPI-PET is an emerging tool for assessing fibrotic disease. |
| Pathology | Dense lymphoplasmacytic infiltrate with many IgG4+ plasma cells Scattered eosinophils Storiform fibrosis Obliterative phlebitis rare | Scant lymphoplasmacytic infiltrate with scattered IgG4+ plasma cells Storiform fibrosis predominant Obliterative phlebitis predominant |
| Treatment | Typically responsive to glucocorticoids and B-cell depletion | Glucocorticoids and B-cell depletion halt progression, but fibrosis is often not reversible. |