Dr. Kevin Yip

Dr Kevin Yip
Orthopaedic Surgeon
MBBS(UK), FRCS(EDIN), FAM(SING), FHKCOS(ORTHO)

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Eosinophilic Granuloma

Basics
Description
  • EOG is the bony, and most common, manifestation of a group of nonneoplastic disorders known as LCH.
  • 3 basic scenarios occur:
    • Solitary site bone disease
    • Multiple bone lesions without visceral disease
    • Multiple bone lesions and visceral disease
  • EOG commonly affects the skull, ribs, pelvis, spine, diaphysis of long bones, and mandible, but any bone may be involved.
  • It more commonly affects a single bone rather than multiple bones.
  • LCH:
    • Spectrum of disease involvement rather than separate specific entries
    • In the past, divided into 3 separate conditions:
      • EOG: Single intramedullary site of bone disease
      • Hand-Schuller Christian disease: Multiple sites of bone disease and visceral disease (skin, lymph nodes, liver, spleen, etc.); the classic triad (Christian triad) (uncommon by itself) involves lytic skull disease, exophthalmos, and diabetes insipidus.
    • Letter-Siwe disease: Fulminant condition in young children (<2 years old) with widespread involvement that often results in death (lymphadenopathy, hepatosplenomegaly, and extensive pulmonary disease)
  • Synonyms: Histiocytosis X; Langerhans cell histiocytosis; Reticuloendotheliosis
Epidemiology
Incidence
Rare
 
Prevalence
  • Usually seen in patients <30 years old, with a peak incidence at age 5-10 years
  • Male:Female ratio of 2:1
Etiology
  • The cause of the accumulation of abnormal metabolic products in the reticuloendothelial cells is unknown.
  • An inflammatory response occurs around these cells and produces the lytic destruction of bone.
Diagnosis
  • 3 diagnostic criteria for LCH of the spine
  • Percutaneous needle biopsy is a very effective method of establishing the diagnosis
Signs and Symptoms
  • Local pain
  • Swelling, tenderness
  • Warmth at the site of involvement
  • Occasional fever
Physical Exam
  • The skull and skeleton should be palpated for areas of tenderness.
  • Note the position of the eyes within the orbit.
  • The spine should be percussed for tenderness.
  • The patient’s gait should be observed for the presence of a limp.
Tests
Lab
  • Elevated ESR
  • Peripheral eosinophilia
Imaging
  • Radiography:
    • Plain radiographs show sharply circumscribed, punched-out lytic lesions.
    • As the lesion heals, a thick rim of reactive bone forms around the periphery.
    • The cortex may be destroyed with endosteal scalloping, periosteal reaction, and expansion of the bone.
    • If the cortex is destroyed unevenly (EOG attacks cortex from within the canal, but 1 side of the cortex may be more involved than the other), a hole within a hole appearance ensues.
    • In the vertebra, the body may collapse to a slender sclerotic wafer of bone called vertebra plana.
    • In the mandible and maxilla, the lytic lesion appears as a floating tooth.
  • Bone scanning usually is not recommended because the lesions may not be hot on bone scan.
Pathological Findings
  • Sheets of foamy (lipid-filled) histiocytes:
    • Coffee-bean-shaped nucleus
    • Crisp nuclear membrane
    • Abundant pale eosinophilic cytoplasm
    • Staining with S-100 and Cd1a stains (1)
  • Inflammatory cells found around these histiocytes:
    • Predominantly eosinophils, but also a few lymphocytes, neutrophils, and giant cells
Differential Diagnosis
  • Ewing sarcoma
  • Lymphoma
  • Osteomyelitis
  • EOG appropriately is called the great imitator because it may mimic infection or neoplasm.
Treatment
General Measures
  • Most lesions are self-limiting and resolve spontaneously.
  • Options include:
    • Observation
    • Curettage and bone grafting
    • Injection with steroids
  • If a pathologic fracture is impending, or the articular surface is in danger, curettage and bone grafting are necessary.
  • Biopsy often is necessary except for characteristic spine lesions.
Medication
  • Methylprednisolone acetate injected into the lesion is effective in >90% of patients, with excellent bone healing.
  • For patients with systemic disease with constitutional symptoms, chemotherapy with methylprednisolone, methotrexate, doxorubicin (Adriamycin), and other agents is indicated.
  • Vertebra plana usually heals itself, and vertebral body height is restored with time.
Surgery
  • Surgery is unnecessary in most cases.
  • However, curettage and bone grafting with or without internal fixation are indicated if nonoperative measures fail and pathologic fracture seems imminent.
Follow-up
Complications
  • Pathologic fractures may occur.
    • Usually heal well with closed or operative treatment
Patient Monitoring
Observation with plain radiographs is indicated if the diagnosis is clear-cut and the patient has no impending fracture, until lesions resolve (usually 6 months).
 
Miscellaneous
Codes
ICD9-CM
277.8 EOG
 
Patient Teaching
  • Reassure the patient and family about the self-limiting nature of most lesions.
  • Make sure that the child and parents understand the need for close follow-up care.
  • Make sure disease progression is not occurring.
  • Ensure that this is not the initial presentation of widespread disease.
Activity
No restrictions are placed on activity unless the patient has an impending pathologic fracture.
 
FAQ
Q: Is EOG or LCH a malignant condition?
A: No. It is a self-limited inflammatory process.
 
Q: What is the prognosis when a single bone is involved?
A: The prognosis is excellent.
 
Q: Do patients with complete vertebral collapse need surgery?
A: Patients with complete vertebral collapse can be treated symptomatically, and only ~10% of patients with LCH of the spine need reconstructive surgery at long-term follow-up.

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