The epidermis consists of multiple layers and cells. From deep to superficial the layers include: stratum basale, spinosum, granulosum, lucid, and corneum. Keratinocytes synthesize the protein keratin. Stem cells differentiate into keratinocytes. Melanocytes synthesize the pigmented protein melanin. Tactile/Merkel cells are associated with a dermal nerve fiber, together called a tactile disc and function in reception for touch. Dendritic/Langerhans cells function in immune response.
The skeleton is the most commonly involved organs system in Langerhans cell histiocytosis (LCH) and is by far the most common location for single lesion, often referred to as eosinophilic granuloma (EG) (the terms are used interchangeably in this article). For a general discusion of this disease please refer to the article on Langerhans cell histiocytosis (LCH). Read more: http://radiopaedia.org/articles/skeletal-manifestations-of-langerhans-cell-histiocytosis