Histiocytosis is a general name for a group of syndromes where immune cells known as histiocytes (monocytes/macrophages) proliferate and mistakenly attack the body instead of infections. There are three major types of histiocytosis:
Class I. Langerhans cell histiocytosis (LCH; previously known as Histiocytosis X)
Class II. Hemophagocytic lymphohistiocytosis (HLH; non-Langerhans)
Class III. T-cell Lymphoma, also known as malignant histiocytosis syndrome.
The excessive increase in the number of histiocytes may form inflammatory tumors in various body organs and bones, including the skull. For example, Langerhans cells infiltrating the lungs leads to inflammation and stiffening of the lungs. Tumors in weight-bearing bones, such as the legs or spine, may cause the bones to fracture without cause.
DIAGNOSTIC TESTING, PHYSICAL FINDINGS, AND ICD-9-CM CODING
Diagnostic testing: Biopsy of skin or bone marrow documenting the presence of Langerhans or T-cell lymphoma. HLH requires a set of defined criteria, including hemophagocytosis on tissue biopsy, cytopenia, low fibrinogen levels, splenomegaly, fever, and rash. Bone imaging studies; complete blood counts (CBC); bronchoscopy with biopsy; chest x-ray; and pulmonary function tests support the diagnosis and provide information on clinical severity.
Physical findings: Symptoms and signs depend on specific organ involvement. In children, these may include abdominal pain, rash, bone pain, delayed puberty, growth failure due to pituitary involvement, irritability, failure to thrive, mental deterioration, seizures, headache, and frequent urination due to diabetes insipidus. Children over age 5 usually only have bone involvement. Adults may experience bone pain, cough and shortness of breath, fever, frequent urination, weight loss, and rash.
ONSET AND PROGRESSION
LCH is relatively more common in children than in adults. The prognosis for children is highly variable, with infants and young children more likely to have systemic disease that leads to death. Adults with pulmonary histiocytosis X have a poor prognosis. In familial HLH, only 21-25% survives 5 years after diagnosis.
These disorders are treated with corticosteroids, anti-cancer immunosuppressive drugs, radiation, and surgery, as well as supportive treatment.
3.02 A or B
103.02 A or B
Listing level severity must be documented.
In children, solitary histiocytosis or eosinophilic granuloma treated with complete surgical excision does not meet listing level severity.