A blue nevus is a type of coloured mole, typically a single well-defined blue-black

bump Bump or bumps may refer to: Arts and entertainment * Bump (dance), a dance from the 1970s disco era * ''BUMP'' (comics), 2007-08 limited edition comic book series Fictional characters * Bobby Bumps, titular character of a series of American si ...

. The blue colour is caused by the pigment being deep in the skin. Diagnosis is by visualisation and dermoscopy. A biopsy is sometimes performed, or the whole lesion surgically removed. The outcome is generally good but there is a small chance of cancerous transformation. Differential diagnosis includes dermatofibroma and

melanoma Melanoma is the most dangerous type of skin cancer; it develops from the melanin-producing cells known as melanocytes. It typically occurs in the skin, but may rarely occur in the mouth, intestines, or eye (uveal melanoma). In very rare case ...

. Blue nevi are more common in females than males. It was first studied in 1906 by Tièche, a student of Josef Jadassohn.

Classification

Blue nevi may be divided into the following types: * A ''patch blue nevus'' (also known as an "acquired dermal melanocytosis", and "dermal melanocyte hamartoma") is a cutaneous condition characterized by a diffusely gray-blue area that may have superimposed darker macules. * A ''blue nevus of Jadassohn–Tièche'' (also known as a "common blue nevus", and "nevus ceruleus") is a cutaneous condition characterized by a steel-blue

papule A papule is a small, well-defined bump in the skin lesion, skin. It may have a rounded, pointed or flat top, and may have a umbilication, dip. It can appear with a Peduncle (anatomy), stalk, be thread-like or look warty. It can be soft or firm a ...

or nodule. * A ''cellular blue nevus'' is a cutaneous condition characterized by large, firm, blue or blue-black nodules. * An ''epithelioid blue nevus'' is a cutaneous condition most commonly seen in patients with the Carney complex. * A ''deep penetrating nevus'' is a type of benign melanocytic skin tumor characterized, as its name suggests, by penetration into the deep

dermis The dermis or corium is a layer of skin between the epidermis (skin), epidermis (with which it makes up the cutis (anatomy), cutis) and subcutaneous tissues, that primarily consists of dense irregular connective tissue and cushions the body from s ...

and/or subcutis. Smudged chromatic is a typical finding. In some cases mitotic figures or atypical melanocytic cytology are seen, potentially mimicking a malignant melanoma. Evaluation by an expert skin

pathologist Pathology is the study of disease. The word ''pathology'' also refers to the study of disease in general, incorporating a wide range of biology research fields and medical practices. However, when used in the context of modern medical treatme ...

is advisable in some cases to help differentiate from invasive

. * An ''amelanotic blue nevus'' (also known as a "hypomelanotic blue nevus") is a cutaneous condition characterized by mild atypia and pleomorphism. * A ''malignant blue nevus'' is a cutaneous condition characterized by a sheet-like growth pattern,

mitoses Mitosis () is a part of the cell cycle in eukaryotic cells in which replicated chromosomes are separated into two new nuclei. Cell division by mitosis is an equational division which gives rise to genetically identical cells in which the ...

necrosis Necrosis () is a form of cell injury which results in the premature death of cells in living tissue by autolysis. The term "necrosis" came about in the mid-19th century and is commonly attributed to German pathologist Rudolf Virchow, who i ...

, and cellular atypia. blue nevus - intermed mag.jpg,

Micrograph A micrograph is an image, captured photographically or digitally, taken through a microscope or similar device to show a magnify, magnified image of an object. This is opposed to a macrograph or photomacrograph, an image which is also taken ...

of a blue nevus showing the characteristic pigmented

melanocyte Melanocytes are melanin-producing neural-crest, neural crest-derived cell (biology), cells located in the bottom layer (the stratum basale) of the skin's epidermis (skin), epidermis, the middle layer of the eye (the uvea), the inner ear, vagina ...

s between bundles of

collagen Collagen () is the main structural protein in the extracellular matrix of the connective tissues of many animals. It is the most abundant protein in mammals, making up 25% to 35% of protein content. Amino acids are bound together to form a trip ...

H&E stain Hematoxylin and eosin stain ( or haematoxylin and eosin stain or hematoxylin–eosin stain; often abbreviated as H&E stain or HE stain) is one of the principal tissue stains used in histology. It is the most widely used stain in medical diag ...

SkinTumors-408.jpg, Blue nevus SkinTumors-415.jpg, Cellular blue nevus SkinTumors-456.jpg, Epithelioid blue nevus Skin Tumors-P6231211.jpg, Malignant blue nevus

References

External links

{{Skin tumors, nevi and melanomas Melanocytic nevi and neoplasms

Classification

See also

References

External links