Localized forms have a good prognosis whereas multiorgan disease, especially in younger than 2 years, have poor outlook.
Congenital cases and familial cases have been rarely reported
Three entities are recognized:
Children from 3months-3 years
Hepatosplenomegaly, lymphadenopathy and cutaneous lesions
Skin lesions on the scalp, face, mouth, neck, trunk and buttocks
Children from 2-6 years
Otitis media, diabetes insipidus, cranial bone defects, exophthalmia and cutaneous lesions.
Skin lesions on chest, axillae and groin
Accounts for 60% of the cases
Affects mainly skeleton (monostotic or polyostotic)
Bones, specially long bones, are the most common location of involvement
Radiologically lytic with punched out appearance
50% in spine, skull, pelvis, ribs and mandibula
Children from 2-5 years
Osteolytic, pulmonary, cutaneous and occasional cranial lesions
Skin lesions on the scalp, face, oral cavity and groin
Fig 60 - Langerhans Histiocytosis - Cellular smears with multiple single Langerhans cells. These cells have convoluted nuclei and prominent grooves and fine vesicular chromatin. Eosinophils in the background (H&E)
Fig 61- Langerhans Histiocytosis –Nuclear details -convoluted aspects of Langerhans nuclei (H&E)
Fig 62 - Langerhans Histiocytosis – CD1a immunostaining showing intense cytoplasmic positivity
Cellular smears with discohesive cells.
Large cells with convoluted nuclei and prominent grooves.
Fine vesicular chromatin.
Abundant pale or granular cytoplasm with well-defined borders
Macrophages with phagocytosis can be a feature.
Mitosis are rare
Eosinophils and other inflammatory cells.
Necrosis can be seen-(eosinophilic micro abscesses)
Special Stains and Immunocytochemistry
CD1a: Positive (essential for diagnosis)
CD68: Positive ( 96% of the cases)
Reactive processes with histiocytic proliferation
Affects mainly adults
Located in soft tissue
Letterer-Siwe´s disease: Mortality in one year
Hand-Shüller-Christian disease: Poor prognosis -50% mortality rate
Eosinophilic Granuloma : Benign