D89.84

HCC Category Mapping

What This Code Means

A chronic inflammatory condition where IgG4 antibodies accumulate in various organs, causing inflammation, fibrosis, and organ dysfunction.

Coding Tips

• •Document which organ systems are involved (pancreas, salivary glands, lungs, etc.) as this affects clinical management
• •Ensure elevated serum IgG4 levels and tissue biopsy findings are documented to support the diagnosis

Clinical Significance

IgG4-related disease is a chronic fibro-inflammatory condition characterized by tumefactive lesions with dense lymphoplasmacytic infiltration rich in IgG4-positive plasma cells, storiform fibrosis, and often elevated serum IgG4 levels. It can affect virtually any organ, most commonly the pancreas (autoimmune pancreatitis), salivary glands, lacrimal glands, retroperitoneum, and kidneys. Despite its often indolent course, untreated disease leads to progressive organ damage and fibrosis.

Documentation Requirements

• ✓Documentation must confirm IgG4-related disease with supporting evidence including elevated serum IgG4 levels, characteristic histopathologic features on biopsy (dense IgG4-positive plasma cell infiltrate, storiform fibrosis, obliterative phlebitis), and affected organ systems.
• ✓The American College of Rheumatology/European Alliance of Associations for Rheumatology classification criteria should be referenced.
• ✓Treatment with corticosteroids or rituximab and response should be documented.

Commonly Confused Codes