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

bump Bump or Bumps may refer to: * A collision or impact * A raised protrusion on the skin such as a pimple, goose bump, prayer bump, lie bumps, etc. Infrastructure and industry * Coal mine bump, a seismic jolt occurring within a mine * Bump (u ...

. The blue colour is caused by the pigment being deep in the skin. Diagnosis is by visualisation and

dermoscopy Dermatoscopy also known as dermoscopy or epiluminescence microscopy, is the examination of skin lesions with a dermatoscope. It is a tool similar to a camera to allow for inspection of skin lesions unobstructed by skin surface reflections. The de ...

. 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 A dermatofibroma, or benign fibrous histiocytomas, is a benign nodule in the skin, typically on the legs, elbows or chest of an adult. It is usually painless. It usually ranges from 0.2cm to 2cm in size but larger examples have been reported. It ...

and

melanoma Melanoma, also redundantly known as malignant melanoma, is a type of skin cancer that develops from the pigment-producing cells known as melanocytes. Melanomas typically occur in the skin, but may rarely occur in the mouth, intestines, or eye ( ...

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

Josef Jadassohn Joseph (Josef) Jadassohn (10 September 1863, Liegnitz – 24 March 1936, Zurich) was a German dermatologist. Biography He was an assistant to Albert Neisser at the Allerheiligen Hospital in Breslau until 1892, the director of the universit ...

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. It may have a rounded, pointed or flat top, and may have a dip. It can appear with a stalk, be thread-like or look warty. It can be soft or firm and its surface may be rough or smooth. Some h ...

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 Carney complex and its subsets LAMB syndrome and NAME syndrome are autosomal dominant conditions comprising myxomas of the heart and skin, hyperpigmentation of the skin (lentiginosis), and endocrine overactivity. It is distinct from Carney's tr ...

. * 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 (with which it makes up the cutis) and subcutaneous tissues, that primarily consists of dense irregular connective tissue and cushions the body from stress and strain. It is divided i ...

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 the causal, causes and effects of disease or injury. 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 us ...

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 Atypia (from Greek, ''a'' + ''typos'', without type; a condition of being irregular or nonstandard) is a histopathologic term for a structural abnormality in a cell, i.e. it is used to describe atypical cells. Atypia can be caused by an infection ...

and

pleomorphism Pleomorphism may refer to: * Pleomorphism (cytology), variability in the size and shape of cells and/or their nuclei * Pleomorphism (microbiology), the ability of some bacteria to alter their shape or size in response to environmental conditions ...

. * A ''malignant blue nevus'' is a cutaneous condition characterized by a sheet-like growth pattern,

mitoses In cell biology, mitosis () is a part of the cell cycle in which replicated chromosomes are separated into two new nuclei. Cell division by mitosis gives rise to genetically identical cells in which the total number of chromosomes is maintai ...

necrosis Necrosis () is a form of cell injury which results in the premature death of cells in living tissue by autolysis. Necrosis is caused by factors external to the cell or tissue, such as infection, or trauma which result in the unregulated dige ...

, and cellular

. blue nevus - intermed mag.jpg,

Micrograph A micrograph or photomicrograph is a photograph or digital image taken through a microscope or similar device to show a magnified image of an object. This is opposed to a macrograph or photomacrograph, an image which is also taken on a mic ...

of a blue nevus showing the characteristic pigmented

melanocyte Melanocytes are melanin-producing neural crest-derived cells located in the bottom layer (the stratum basale) of the skin's epidermis, the middle layer of the eye (the uvea), the inner ear, vaginal epithelium, meninges, bones, and heart. ...

s between bundles of

collagen Collagen () is the main structural protein in the extracellular matrix found in the body's various connective tissues. As the main component of connective tissue, it is the most abundant protein in mammals, making up from 25% to 35% of the whole ...

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 diagnos ...

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