Pulmonary Pathology Online
Pathology of Langerhans Cell
Histiocytosis (Histiocytosis X)
The Langerhans cell histiocytoses (also referred to as Histiocytosis X) represent clonal proliferations of the antigen-presenting dendritic cells, which are normally found in many organs.
There are three types of histiocytoses:
- True histiocytic lymphomas (rare).
- Benign reactive histiocytoses.
- Langerhans cell histiocytoses
A disarray of immune regulation has been implicated in the pathogenesis of Langerhans cell histiocytosis .
Microscopically, the single most important diagnostic feature of Langerhans cell histiocytosis is the morphology of the lesional cell.
The cell is large with fairly abundant eosinophilic finely vacuolated cytoplasm.
The nucleus is indented or reniform, and are generally single and conspicuous.
Mitoses are unusual. Phagocytotic activity is rare.
The Langerhans cell displays immunoreactivity (cytoplasmic and nuclear) for S-100 protein and the monoclonal antibody CD1a , HLADR (Ia) and peanut agglutinin.
Ultrastructurally, the Birbeck (or X) granule is straight or curved pentalaminary rod of variable length, often vesicular at one end frequently resembling a racquet.
A variable light microscopic picture relates to different phases of lesion.
- The proliferative stage is composed chiefly or exclusively of Langerhans cells.
- The granulomatous stage shows necrosis, lymphocytes and polymorphs (especially eosinophils), in addition to Langerhans cells.
- The xanthogranulomatous stage shows an accumulation of lipid in histiocytic cell cytoplasm and a prominence of fibrous tissue. Langerhans cells may be difficult to find in such lesions.
The skeleton is the most common location for Langerhans cell histiocytosis.
Lesions limited to bone are referred to as eosinophilic granulomas. These osseous lesions are usually solitary. Children are affected more commonly than adults.
The skin is the second most common site. Case Link
Exclusive dermal involvement is extremely uncommon and involvement of the skin usually occurs as part of a disseminated process. Microscopically, the papillary dermis is the site of histiocytic proliferation and the basement membrane of the epidermis is frequently disrupted. Giant cells tend to be uncommon in skin lesions.
Clinical Features and Prognosis:
Three patterns of disease are recognized, each with a different course and prognosis :
1. Unifocal Langerhans cell histiocytosis (unifocal eosinophilic granuloma):
Usually affects the skeletal system as an erosive, expanding accumulation of Langerhans cells within calvarium, ribs, or femur. It may also occur in skin, lungs, or stomach.
Lesions may be asymptomatic or painful. Pathologic fractures may occur.
This is an indolent disorder of children and young adults, especially men.
It may remit spontaneously or be cured by local excision or irradiation.
2. Multifocal Langerhans cell histiocytosis:
Usually affects children, who present with fever, diffuse eruptions, particularly on the scalp and in the ear canals, frequent bouts of otitis media, mastoiditis, and upper respiratory tract infections, bone lesions and mild lymphadenopathy, hepatomegaly, and splenomegaly.
In about 50% of patients, the posterior pituitary stalk of the hypothalamus is involved, leading to diabetes insipidus.
The combination of calvarial bone defects, diabetes insipidus and exophthalmos is referred to as the Hand-Schuller-Christian triad.
Spontaneous regression may be seen. Persistent disease is treated with chemotherapy.
3. Acute disseminated Langerhans cell histiocytosis (Letterer-Siwe disease):
Occurs most frequently before 2 years of age.
This is an aggressive systemic disorder in which Langerhans histiocytes infiltrate and proliferate within skin, spleen, liver, lung, and bone marrow.
Anemia and destructive bony lesions are seen.
Letterer-Siwe disease is rapidly fatal if untreated.
With intensive chemotherapy, 5-year survival is about 50%.
Pulmonary Langerhans cell histiocytosis is a rare interstitial lung disease in adults that is a part of diseases caused by infiltration of Langerhans cell across multiple organs, such as the lungs, bones, skin, pituitary gland, and lymph node.
Choi YS, Lim JS, Kwon W, et al. Pulmonary Langerhans Cell Histiocytosis in an Adult Male Presenting with Central Diabetes Insipidus and Diabetes Mellitus: A Case Report. Tuberculosis and Respiratory Diseases. 2015;78(4):463-468. doi:10.4046/trd.2015.78.4.463.
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