Melanocytic tumors

Melanocytic tumors belong to the neuroectoderm tumors. They arise from melanocyte, which are cells capable of producing melanin. Most non-tumor melanocytes are stored in the epidermis, dermis and hair follicles. However, these cells can also be found in the mucous membranes, eyeball or meninges. They probably arise from '' pluripotent cells [neural bars] and migrate through the paraspinal ganglia, peripheral nerves to the epidermis.

Melanocytic tumors include non-cellular nevi and malignant melanomas.

Non-cellular nevi

 * These are benign tumors occurring mainly in the skin, mucous membranes andeyeball'''.
 * They most often occur in the skin, where we call them a birthmark or  melanocytic nevus.
 * They may be congenital or acquired, where acquired are more common and are associated with UV radiation and inflammatory  cytokines.
 * In the microscope, they look like nests of accumulated melanocytes in the basal layer of the epidermis or in various parts of the dermis.

Malignant melanomas

 * They are  malignant tumors.
 * They occur less often than non-cellular, but their incidence increases faster than other tumors.
 * It is one of the  worst prognosis  tumors.
 * They can occur in the skin, eyeballs, and Brain Covers.
 * Rarely occur around the prostate or internal genitalia of women, in the mucous membranes of the oral, nasal and distal rectum.
 * Tumor cells have an  atypical character  (prominent nuclei and nucleoli) and increased mitotic activity, including atypical mitoses.
 * Tumor cells can grow.
 * Superficially spreading melanoma - grows horizontally and does not reach deeper layers.
 * Nodular melanoma - spreads vertically and extends into the deeper layers and subcutaneous adipose tissue.
 * Lentigo maligna melanoma - spreads radially and later vertically, is typical of the elderly.
 * Malignant melanoma looks like a  birthmark with  irregular edges '', irregularly colored. It may  itch or hurt , and gradually  increases.
 * In the advanced stage, melanoma has a dark color.
 * Melanocytes are  irregularly distributed at different heights of the epidermis.
 * Tumor margins are formed by individual melanocytes.

Related Articles

 * Melanoma
 * Skin nevi
 * Examination of the child's skin and skin adnexa

Source

 * ws:Melanocytární nádory