IgG4-related systemic diseases

The IgG4-related systemic diseases, also IgG4-related diseases, are diseases characterized IgG4 positive plasma cells and fibrosis.

List of IgG4-related diseases

• Lymphoplasmacytic sclerosing pancreatitis - a type of autoimmune pancreatitis.
• Retroperitoneal fibrosis.
• Riedel's thyroiditis.
• Inflammatory pseudotumour, also known as inflammatory myofibroblastic tumour (IMT); probably only a subset of IMT.

• Sclerosing cholangitis (IgG4-associated cholangitis).
• Autoimmune pancreatitis (lymphoplasmacytic sclerosing pancreatitis).
• Others.

Microscopic

Features:

• At least 10 IgG4 +ve plasma cells.†
• >40% of plasma cells IgG4 +ve.

Note:

• † Minimum number dependent on anatomical site.
  • Lymph node: 100 (or 50) plasma cells/HPF, where 1 HPF ~ 0.196 mm*mm and 3 HPFs (0.588 mm*mm) are assessed.

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Not present

The provided clinical history is noted. Plasma cells are not readily apparent (<10 plasma cells/0.196 mm*mm).

See also

• Plasma cells.
• HPFitis.