Other histiocytosis syndromes

This code represents a group of rare disorders characterized by the abnormal proliferation and accumulation of histiocytes (macrophages) in various tissues and organs, excluding Langerhans cell histiocytosis (LCH) and malignant histiocytic disorders. These syndromes can manifest with diverse clinical presentations depending on the organs involved, often leading to organ dysfunction.

Use this code for diagnoses such as Rosai-Dorfman disease (sinus histiocytosis with massive lymphadenopathy), juvenile xanthogranuloma (JXG) when systemic, or other specified non-LCH, non-malignant histiocytic disorders. Documentation should clearly state a diagnosis of a histiocytosis syndrome that does not fit into LCH or a malignant category, often confirmed by biopsy and immunohistochemistry.

• Do not use this code for Langerhans cell histiocytosis (LCH); refer to codes in the C96 category for malignant histiocytic and mast cell tumors.
• Ensure documentation specifies the type of histiocytosis if known, as more specific codes may exist for certain conditions (e.g., specific types of xanthogranuloma).
• Code any associated organ manifestations or complications separately, such as hepatomegaly or splenomegaly, as secondary diagnoses.