Langerhans cell histiocytosis
Updates to Article Attributes
Langerhans cell histiocytosis (LCH) is a rare multi-system disease with a wide and heterogeneous clinical spectrum and variable extent of involvement.
Terminology
Langerhans cell histiocytosis was previously called histiocytosis X. The newer term is preferred as it's more descriptive of its cellular background, and removes the ambiguity of the connotation "X".
Epidemiology
The disease is more common in the paediatric population, with a peak incidence between one and three years of age 5. Incidence is estimated at ~5 per million children, and 1-2 cases per million adults 8. There is also a male predilection (M:F ~ 1.5:1) 5.
Clinical presentation
Essentially any part of the body can be affected and as such clinical presentation will depend on specific involvement. The course of the disease ranges from those that spontaneously regress to those that have a rapidly progressive course (the latter is especially common in young children with multi-system disease).
Historically, three eponymous forms have been recognised, although there is some confusion as to their definition 1-5:
-
Letterer-Siwe disease
- disseminated multi-organ disease
- typically young children/infants less than one year-old
- fulminant course with poor prognosis
-
Hand-Schüller-Christian disease
- multiple lesions
- some authors confine the term to patients with solitary organ involvement 4
- other authors accept multi-organ involvement (e.g. bone and spleen) 6
- confined to the one bone (usually bone)
- typically children
- intermediate prognosis
- multiple lesions
-
eosinophilic granuloma (EG)
- lesions are confined to one organ system
- some authors confine the term to patients with a solitary lesion 4
- other authors accept multiple lesions 6
- 70% of cases affects bone
- typically children
- best prognosis
- lesions are confined to one organ system
A more useful and less controversial classification, which roughly correlates to the eponymous diseases above, is as follows:
- multiple organ systems, multiple sites involved
- single-organ system, multiple sites involved
- single lesion
Additionally, in 2008 the WHO recommended distinguishing LCH from a more pleomorphic variant known as Langerhans cell sarcoma 3.
As well as systemic disease, individual organ systems may be involved, which will be discussed separately:
- skeletal manifestations of LCH
- cutaneous manifestations of LCH
- central nervous system manifestations of LCH
- hepatobiliary manifestations of LCH
- pulmonary manifestations of LCH
- salivary gland manifestations of LCH
- gastrointestinal manifestations of LCH
The remainder of this article concerns a general overview of LCH.
Pathology
Langerhans cell histiocytosis is due to uncontrolled monoclonal proliferation of Langerhans cells (distinctive cells of monocyte-macrophage lineage) and should be considered a malignancy although its biological behaviour is very variable 1,3. An immune-mediated mechanism has been postulated. This proliferation is accompanied by inflammation and granuloma formation. Electron microscopy may reveal characteristic Birbeck granules. Cells often express:
- HLA-DR
- CD1a
- CD207
- S-100
Radiographic features
Imaging features are often not pathognomonic and tissue diagnosis is usually required for definitive diagnosis. As LCH can affect most organ system, radiographic appearances are discussed separately (see above).
Treatment and prognosis
The prognosis can be extremely variable with eosinophilic granuloma carrying the best and Letterer-Siwe disease-carrying the worst prognosis. The prognosis is more closely related to the disease burden rather than histological features, although frankly malignant features (Langerhans cell sarcoma) do also have an impact on survival 3-4:
- unifocal disease (eosinophilic granuloma): >95% survival
- two organ involvement: 75% survival
- Langerhans cell sarcoma: 50% survival
History and etymology
The Langerhans cell was discovered by German physician Paul Langerhans in 1865 when he was a medical student, based on clinical observations.
Langerhans cell histiocytosis was previously called histiocytosis X. The newer term is preferred as it's more descriptive of its cellular background, and removes the ambiguity of the connotation "X".
See also
- Erdheim-Chester Disease: a non-Langerhans cell histiocytosis
- cystic angiomatosis
- Rosai-Dorfman disease: sinus histiocytosis
- juvenile xanthogranuloma
- Haemophagocytic lymphohistiocytosis
-<p><strong>Langerhans cell histiocytosis (LCH)</strong> is a rare multi-system disease with a wide and heterogeneous clinical spectrum and variable extent of involvement. </p><h4>Epidemiology</h4><p>The disease is more common in the paediatric population, with a peak incidence between one and three years of age <sup>5</sup>. Incidence is estimated at ~5 per million children, and 1-2 cases per million adults <sup>8</sup>. There is also a male predilection (M:F ~ 1.5:1) <sup>5</sup>. </p><h4>Clinical presentation</h4><p>Essentially any part of the body can be affected and as such clinical presentation will depend on specific involvement. The course of the disease ranges from those that spontaneously regress to those that have a rapidly progressive course (the latter is especially common in young children with multi-system disease). </p><p>Historically, three eponymous forms have been recognised, although there is some confusion as to their definition <sup>1-5</sup>:</p><ul>- +<p><strong>Langerhans cell histiocytosis (LCH)</strong> is a rare multi-system disease with a wide and heterogeneous clinical spectrum and variable extent of involvement. </p><h4>Terminology</h4><p>Langerhans cell histiocytosis was previously called histiocytosis X. The newer term is preferred as it's more descriptive of its cellular background, and removes the ambiguity of the connotation "X".</p><h4>Epidemiology</h4><p>The disease is more common in the paediatric population, with a peak incidence between one and three years of age <sup>5</sup>. Incidence is estimated at ~5 per million children, and 1-2 cases per million adults <sup>8</sup>. There is also a male predilection (M:F ~ 1.5:1) <sup>5</sup>. </p><h4>Clinical presentation</h4><p>Essentially any part of the body can be affected and as such clinical presentation will depend on specific involvement. The course of the disease ranges from those that spontaneously regress to those that have a rapidly progressive course (the latter is especially common in young children with multi-system disease). </p><p>Historically, three eponymous forms have been recognised, although there is some confusion as to their definition <sup>1-5</sup>:</p><ul>
-</ul><h4>History and etymology</h4><p>The Langerhans cell was discovered by German physician <strong>Paul Langerhans</strong> in 1865 when he was a medical student, based on clinical observations.</p><p>Langerhans cell histiocytosis was previously called histiocytosis X. The newer term is preferred as it's more descriptive of its cellular background, and removes the ambiguity of the connotation "X".</p><h4>See also</h4><ul>- +</ul><h4>History and etymology</h4><p>The Langerhans cell was discovered by German physician <strong>Paul Langerhans</strong> in 1865 when he was a medical student, based on clinical observations.</p><h4>See also</h4><ul>
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