Basics
Description
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EOG is the bony, and most common, manifestation of a group of nonneoplastic disorders known as LCH.
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3 basic scenarios occur:
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Solitary site bone disease
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Multiple bone lesions without visceral disease
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Multiple bone lesions and visceral disease
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EOG commonly affects the skull, ribs, pelvis, spine, diaphysis of long bones, and mandible, but any bone may be involved.
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It more commonly affects a single bone rather than multiple bones.
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LCH:
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Spectrum of disease involvement rather than separate specific entries
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In the past, divided into 3 separate conditions:
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EOG: Single intramedullary site of bone disease
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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.
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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)
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Synonyms: Histiocytosis X; Langerhans cell histiocytosis; Reticuloendotheliosis
Epidemiology
Incidence
Rare
Prevalence
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Usually seen in patients <30 years old, with a peak incidence at age 5-10 years
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Male:Female ratio of 2:1
Etiology
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The cause of the accumulation of abnormal metabolic products in the reticuloendothelial cells is unknown.
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An inflammatory response occurs around these cells and produces the lytic destruction of bone.
Diagnosis
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3 diagnostic criteria for LCH of the spine
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Percutaneous needle biopsy is a very effective method of establishing the diagnosis
Signs and Symptoms
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Local pain
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Swelling, tenderness
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Warmth at the site of involvement
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Occasional fever
Physical Exam
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The skull and skeleton should be palpated for areas of tenderness.
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Note the position of the eyes within the orbit.
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The spine should be percussed for tenderness.
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The patient’s gait should be observed for the presence of a limp.
Tests
Lab
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Elevated ESR
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Peripheral eosinophilia
Imaging
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Radiography:
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Plain radiographs show sharply circumscribed, punched-out lytic lesions.
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As the lesion heals, a thick rim of reactive bone forms around the periphery.
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The cortex may be destroyed with endosteal scalloping, periosteal reaction, and expansion of the bone.
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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.
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In the vertebra, the body may collapse to a slender sclerotic wafer of bone called vertebra plana.
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In the mandible and maxilla, the lytic lesion appears as a floating tooth.
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Bone scanning usually is not recommended because the lesions may not be hot on bone scan.
Pathological Findings
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Sheets of foamy (lipid-filled) histiocytes:
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Coffee-bean-shaped nucleus
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Crisp nuclear membrane
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Abundant pale eosinophilic cytoplasm
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Staining with S-100 and Cd1a stains (1)
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Inflammatory cells found around these histiocytes:
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Predominantly eosinophils, but also a few lymphocytes, neutrophils, and giant cells
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Differential Diagnosis
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Ewing sarcoma
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Lymphoma
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Osteomyelitis
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EOG appropriately is called the great imitator because it may mimic infection or neoplasm.
Treatment
General Measures
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Most lesions are self-limiting and resolve spontaneously.
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Options include:
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Observation
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Curettage and bone grafting
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Injection with steroids
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If a pathologic fracture is impending, or the articular surface is in danger, curettage and bone grafting are necessary.
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Biopsy often is necessary except for characteristic spine lesions.
Medication
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Methylprednisolone acetate injected into the lesion is effective in >90% of patients, with excellent bone healing.
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For patients with systemic disease with constitutional symptoms, chemotherapy with methylprednisolone, methotrexate, doxorubicin (Adriamycin), and other agents is indicated.
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Vertebra plana usually heals itself, and vertebral body height is restored with time.
Surgery
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Surgery is unnecessary in most cases.
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However, curettage and bone grafting with or without internal fixation are indicated if nonoperative measures fail and pathologic fracture seems imminent.
Follow-up
Complications
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Pathologic fractures may occur.
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Usually heal well with closed or operative treatment
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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
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Reassure the patient and family about the self-limiting nature of most lesions.
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Make sure that the child and parents understand the need for close follow-up care.
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Make sure disease progression is not occurring.
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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.