Findings - Mutliple varying sized lytic lesions with sclerotic and bevelled margins are noted.
Langerhans cell histiocytosis (LCH) is a group of idiopathic disorders characterized by the proliferation of specialized bone marrow–derived Langerhans cells (LCs) and mature eosinophils. The term LCH is generally preferred to the older term, histiocytosis X.
Langerhans cell histiocytosis (LCH) is a group of idiopathic disorders characterized by the proliferation of specialized bone marrow–derived Langerhans cells (LCs) and mature eosinophils. The term LCH is generally preferred to the older term, histiocytosis X.
The working group of the Histiocyte Society has divided histocytic disorders into 3 different groups: (1) dendritic cell histiocytosis, (2) erythrophagocytic macrophage disorders, and (3) malignant histiocytosis. LCH belongs in group 1 and encompasses a number of diseases. The clinical spectrum includes on one end, an acute fulminant, disseminated disease called Letterer-Siwe disease and, on the other end, solitary or few, indolent and chronic, lesions of bone or other organs called eosinophilic granulomas. The intermediate clinical form called Hand-Schüller-Christian disease is characterized by multifocal, chronic involvement and classically presents as the triad of diabetes insipidus, proptosis, and lytic bone lesions.
Age: LCH affects patients from neonates to adults. The age at onset varies according to the variety of LCH.
- Letterer-Siwe disease occurs predominantly in children younger than 2 years.
- The chronic multifocal form, including Hand-Schüller-Christian syndrome, has a peak of onset in children aged 2-10 years.
- Localized eosinophilic granuloma occurs mostly frequently in those aged 5-15 years.
Physical: Signs of LCH depend on the localization and the extent of the disease. The clinical spectrum of LCH is broad, and an individual case may differ markedly from the prototypes described.
- Chronic unifocal LCH (eosinophilic granuloma of bone) classically presents as a solitary calvarial lesion in young adults; other sites of involvement include the vertebra, the rib, the mandible, the femur, the ilium, and the scapula.
- Lesions are usually asymptomatic, but bone pain and a soft tissue mass may occur.
- When the calvarial lesions extend into the nervous system, a variety of neurologic manifestations may be seen.
- Bony lesions may cause otitis media by destruction of the temporal and mastoid bones, proptosis secondary to orbital masses, loose teeth from infiltration of the mandibles, or pituitary dysfunction due to involvement of the sella turcica.
- Spontaneous fractures can result from osteolytic lesions of the long bones, and vertebral collapse with spinal cord compression has occasionally been described.
- Cutaneous disease presents with noduloulcerative lesions in the oral, perineal, perivulvar, or retroauricular regions.
- Pulmonary lesions may be the presenting and only manifestation. In adults, the pulmonary system is most frequently involved.
- Rarely, solitary cerebral lesions may occur.
- The classic multifocal form of LCH (Hand-Schüller-Christian disease) includes diabetes insipidus; exophthalmos; and bony defects, particularly of the cranium.
- Lesions may affect a variety of systems, including the liver (20%), the spleen (30%), and the lymph nodes (50%).
- Pulmonary involvement may occur.
- Osteolytic lesions of the long bones can lead to spontaneous fractures.
- One third of patients have mucocutaneous lesions, most frequently infiltrated nodules and ulcerated plaques, especially in the mouth, the axillae, and the anogenital region. Other cutaneous manifestations include extensive coalescing, scaling, or crusted papules.
- Patients with acute disseminated LCH (multiorgan involvement) present with fever; anemia; thrombocytopenia; pulmonary infiltrates; skin lesions; and enlargement of the lymph nodes, the spleen, and the liver.
- Cutaneous abnormalities are present in almost 80% of patients; frequently, this is the first sign.
- The eruption may be extensive, involving the scalp, the face, the trunk, and the buttocks as well as the intertriginous areas. Lesions consist of closely set petechiae and yellow-brown papules topped with scale and crust. The papules may coalesce to form an erythematous, weeping eruption mimicking seborrheic dermatitis.
- Intertriginous lesions are often exudative, and secondary infection and ulceration may occur.
- Osteolytic lesions are not common in the disseminated form of LCH, but the mastoid can be affected, resulting in a clinical picture of otitis media that may be the presenting complaint. Aural discharge, conductive hearing loss, and postauricular swelling have been described.
- Patients with pulmonary involvement present with chest pain, hemoptysis, dyspnea, failure to thrive, cystic changes, and pneumothorax; if lung disease is extensive, oxygen diffusion and lung capacity may be reduced.
- Neurologic involvement may produce seizures, vertigo, headache, ataxia, and cognitive defects.
Imaging Studies:
Chest radiographs (posteroanterior and lateral)
Chest radiographs (posteroanterior and lateral)
- LCH can present as a micronodular and interstitial infiltrate in the mid zone and base of the lung, with sparing of the costophrenic angles.
- Older lesions show a honeycomb appearance.
- Patients with radiographically demonstrated pulmonary involvement, in whom chemotherapy is being considered, require a biopsy of the lung preceded by bronchoalveolar lavage (BAL) to exclude opportunistic infections. If the BAL is diagnostic, the biopsy of the lung can be obviated.
Skeletal radiograph survey
- Unifocal LCH presents as a single osteolytic lesion, usually affecting long or flat bones (in children, the calvaria and the femur; in adults, the ribs).
- Multifocal LCH show osteolytic lesions involving the calvaria, the sella turcica, the mandible, the vertebrae, and/or the long bones of the upper extremities.
- Although a radionuclide bone scan is suggested for establishing the extent of osseous involvement, the latter is not as sensitive as the skeletal radiograph survey in most patients.
- CT scan or MRI of the hypothalamic-pituitary region may reveal abnormalities of these organs. In particular, magnetic resonance spectroscopy may be valuable in the early detection and evaluation of the neurodegenerative component.