Histiocytosis of Langhans cells

Introduction to histiocytosis of Langhans cells Langerhans' cellhistiocytosis (LCH), also known as Langerhans cell granulomatosis (Langerhan-cellgranulomatosis) is a Langerhans cell proliferative disease that invades the skin and external organs. . The disease can affect the skin, bones, lungs, nervous system and other organs. Clinically, it can be divided into 3 types: Letterer-Siwe disease, Hand-schüller-christian disease and eosinophilic granuloma. However, there is no obvious boundary between the three, often overlapping or changing each other. Generally speaking, if the disease occurs within one year old, it is often characterized by lethal visceral damage, mostly Letterer-Siwe disease, such as in childhood, often Multiple bone damage, while visceral damage is light, that is, Hand-schüller-christian disease; in larger children and adults, the disease is usually limited, often manifested as one or several bone damage, ie eosinophilic Cell granuloma. basic knowledge The proportion of illness: this disease is rare, the incidence rate is about 0.0001% - 0.0002% Susceptible people: no special people Mode of infection: non-infectious complication:

Causes of histiocytosis in Langhans cells

(1) Causes of the disease

The cause is still unknown. Although many studies have considered the incidence of viruses and viruses, immunology and new organisms, there is no convincing evidence. Many scholars have long suspected that the virus is a potential cause of disease, and that Langerhans cells are abnormally proliferated. Abnormal reaction caused by viral infection, Lahey et al found 14 cases (47%) of 30 LCH patients with human herpesvirus-6 DNA (HHV-6DNA), suggesting that the virus is associated with the pathogenesis of LCH, Mcclain et al. On the contrary, no evidence was found for adenovirus, cytomegalovirus, Epstein-Barr virus, herpes simplex virus, HHV-6, human T cell leukemia virus type I and type II, and parvovirus associated with the pathogenesis of LCH. The virus is documented in a convincing literature related to the pathogenesis of LCH.

(two) pathogenesis

In the past 20 years, although many immunological tests have been performed on this disease, the immunological limitations of this disease have not been found. It has been found that LCH-damaged cells have several cytokines such as interleukin I. Tumor necrosis factor alpha, granulocyte-macrophage vegetative stimulator, interleukin-8 and leukemia inhibitory factors are significantly increased, and these factors may play a decisive role in causing (promoting) LCH cell growth, but these are not clear The correlation between cytokines and different manifestations of this disease, although the X-chromosome inactivation assay suggests that LCH cells may be vegetatively propagated, but these cells do not exhibit asexual reproduction of T cell receptor gene recombination, and these findings combine damage Flow cytometric DNA analysis, and LCH can naturally resolve, suggesting that LCH is a non-neoplastic disease.

Prevention of histiocytosis in Langhans cells

There is no effective preventive measure for this disease. Early detection and early diagnosis are the key to the prevention and treatment of this disease.

Complications of histiocytosis in Langhans cells Complication

The disease is chronic and has a tendency to self-heal. In rare cases, eosinophilic granuloma can develop into Hand-Schüller-christian disease.

Symptoms of histiocytosis in Langhans cells Common symptoms Hairy eye disease Hepatomegaly Histiocytosis Lymph node enlargement Mucosal damage Spontaneous fracture Thrombocytopenia Breathing difficulty Scarring

1. Letterer-Siwe disease (LSD)

For acute disseminated Langerhans cell histiocytosis, extensive damage, multiple organ involvement, systemic symptoms aggravated, infancy onset, 1/3 of cases occurred within 6 months after birth, most of 2/3 Also in the 2 years old, even in larger children and adults, 80% of patients with skin damage, often the first symptoms of this disease, have diagnostic value, typical lesions are small and translucent papules, lesions are extensive and dense, The diameter is 1~2mm, slightly higher, the color is light brown, the surface is covered with scales, often accompanied by licking points, which occur in the head, trunk and wrinkles (behind the ears, armpits and genitals); Skin lesions tend to fuse, showing a seborrheic dermatitis-like appearance; those occurring in wrinkles, similar to rubbing, mucous membranes showing erosions and ulcers, but rare, in addition, there are still paronychia, nail fold damage, nail stripping, underarm corner Excessive hyperthyroidism and nail bed purple, the above symptoms indicate good prognosis, and purpura suggests poor prognosis. The systemic symptoms of this disease are common in the lungs. In children with more than 1/2, there may be difficulty breathing, cyanosis, pneumothorax. , the lungs can show the appearance of a typical hive Lung damage symptoms vary, the light can be asymptomatic, can be lethal, liver enlargement is a common systemic damage, especially associated with severe jaundice, then a poor prognosis.

Splenomegaly is not common, 25% to 75% of deaths can be seen in lymph nodes, 60% of patients with bone damage, common in flat bone, vertebrae and skull, osteolytic lesions can be asymptomatic or associated with pain and functional impairment , usually multiple, and gradually appear, chronic otitis media is common, hematopoietic system is rare, such as spontaneous thrombocytopenia and severe anemia often cause death, patients often have fever, rapid development of the disease, in general, poor prognosis, However, even if there are only skin lesions without systemic symptoms, the prognosis is good.

2.Hand-schüller-christian disease (HSCD)

For chronic disseminated Langerhans cell histiocytosis, 70% of cases occur 2 to 7 years after birth, 91% of patients occur before the age of 30, typical systemic symptoms are diabetes insipidus, exophthalmos and bone damage , but any one or all of the symptoms can be absent, of which bone damage is the most common, about 80% of cases occur, occur in the skull, especially the parietal bone, the lesion is a localized osteolytic area, showing a typical map appearance The mandibular osteolytic lesions are also common. The bone lesions in the mastoid area can cause otitis media. Diabetes insipidus is seen in more than 50% of cases. It is common in patients with skull and tibia involvement. The eye syndrome occurs later, seen in 10%~ 30% of patients were unilateral or bilateral, less than 20% of patients with pulmonary infiltration; hepatomegaly and lymphadenopathy are rare, about 1/3 of patients with skin lesions, skin lesions are classified into 3 types, the most common is invasive plaque Block, can form ulcers, especially the armpits, groin, mouth, labia, followed by a wide range of scaly or crusting papules as seen in Letterer-siwe disease, type 3 skin lesions are rare, scattered in soft Light yellow papular yellow tumor, the latter in clinical and tissue diseases And are not easy to distinguish the juvenile xanthogranuloma, immunohistochemistry and electron microscopy requires the use distinction, constant course of the disease for several years, without treatment about 30% of patients can cause death.

3. Eosinophilic granuloma (eosinophilic granuloma)

Chronic localized Langerhans cell histiocytosis, the most common type of Langerhans cell hyperplasia, more common in male patients aged 5 to 30 years, the granulomatous lesions are often single, occurring in the skull Qianlong, ribs, spine, pelvis, scapula and long bones, except for spontaneous fractures and/or otitis media lesions, granulomatous lesions are not easily detected, such as lesions, symptoms, pain, tenderness and soft tissue swelling, skin Mucosal damage is rare and can be divided into 2 types. Type 1 is a widespread scarring papule as seen in Letterer-Siwe's disease and Hand-schüller-christian's disease or 1 to several red invasive plaques as seen in Hand-schüller-christian disease. It tends to form ulcers; type 2 lesions can occur at the same time. The disease is chronic and has a tendency to heal. In rare cases, eosinophilic granuloma can develop into Hand-Schüller-christian disease.

Classification was performed in conjunction with immunohistochemistry.

Examination of histiocytosis of Langhans cells

Histopathology: Langerhans cells are about 4 to 5 times more than lymphocytes, with irregular nuclei and vacuoles. The nucleus is often kidney-shaped and rich in light eosinophilic cytoplasm. There are three kinds of tissue reactions, namely hyperplasia, granulation. Swollen and xanthomatous, there is no clear boundary between type 3 tissue reactions, but overlap, but the relationship between tissue reaction type and clinical disease classification is still clear. In general, almost pure Langerhans cell infiltration The proliferative response is a typical tissue manifestation of Letterer-Siwe's disease. The granulomatous reaction is a typical manifestation of eosinophilic granuloma. The xanthomatous reaction is a typical manifestation of Hand-Schüller-Christian disease. In a few organs, there is not necessarily a lipid-containing cell in the lesion of the disease.

1. Histopathological features of skin proliferative response

In order to have a wide range of Langerhans cell infiltration, infiltration usually closes the epidermis and invades the epidermis, and even destroys the epidermis to cause ulceration. The infiltrating cells are large and round, rich in light eosinophilic cytoplasm, and the nuclei are often biased to one side. Incision or kidney shape, in some patients with acute and lethal disease, especially in infants, the nucleus is pleomorphic or even atypical, showing large nuclei and irregular shape, deep staining, common in infiltrating cell aggregation areas. Erythrocyte extravasation, occasionally some infiltrating cells are foamy, in the persistent damage, a small number of multinucleated giant cells can be seen, suggesting a transition to granuloma.

2. Granulomatous reaction

Extensive Langerhans cell infiltration, often extended to the deep dermis, a number of eosinophils, infiltrating cells often clustered, common multinucleated giant cells, some neutrophils, lymphoid Cells and plasma cells, common red blood cells extravasation, but real foam cells are not common.

3. Xanthomatic reaction

It is characterized by a large number of foam cells in the dermis, a number of Langerhans cells and eosinophil infiltration, common multinucleated giant cells, mainly foreign bodies, and occasionally Touton giant cells (the lipid-containing giant) cell).

Immunohistochemical examination: LCH cells are normal cellular Langerhans tissue immunophenotype, these cells express high level of histocompatibility complex (MHC) group II molecules, S-100 protein, CDIa complex and CD4 molecules; Unlike Langerhans cells, LCH cells also express several macrophage-associated markers, including CD11C, CDW32, and CD68. There are few reliable markers that distinguish LCH cells from normal skin Langerhans cells, but there are three markers, the placenta. Alkaline phosphatase (PLAP), peanut agglutinin (PNA) and interferon-gamma receptor (IFN-R) are particularly valuable for distinguishing normal Langhans cells from LCH cells.

Ultramicroscopic examination: About 50% of LCH tissue cells contain Birbeck particles.

Diagnosis and differentiation of histiocytosis of Langhans cells

Differential diagnosis

1. Acute disseminated Langerhans cell histiocytosis represented by Letterer-Siwe disease should be differentiated from seborrheic dermatitis, follicular keratosis, generalized candidiasis, LS disease in infants and young children. The systemic symptoms and systemic symptoms are obvious. The skin lesions are often accompanied by purpura, which is characterized by histological examination. Histopathological examination can confirm the diagnosis.

2. Chronic disseminated Langerhans cell histiocytosis represented by Hand-Schüller-Christian disease and plaque of chronic localized Langerhans cell histiocytosis represented by eosinophilic granuloma Nodular and xanthomatous lesions should be differentiated from juvenile yellow granuloma, disseminated xanthoma, cutaneous yellow tumor, mast cell hyperplasia, benign head histiocytosis.

HSC disease and eosinophilic granuloma immunohistochemical staining for S-100 protein and CDIa positive, ultramicroscopic examination of Birbeck particles, can be identified with the above diseases.

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