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Type of melanocytic tumor
Medical condition
A blue nevus is a type of coloured mole, typically a single well-defined blue-black bump.[1][2]
The blue colour is caused by the pigment being deep in the skin.[4]
Diagnosis is by visualisation and dermoscopy.[4] A biopsy is sometimes performed, or the whole lesion surgically removed.[3] The outcome is generally good but there is a small chance of cancerous transformation.[3] Differential diagnosis includes dermatofibroma and melanoma.[3]
Blue nevi are more common in females than males.[2] It was first studied in 1906 by Tièche, a student of Josef Jadassohn.[6]
Blue nevi may be divided into the following types:[7]: 701
- 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.[1]
- 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 or nodule.[7]: 701
- A cellular blue nevus is a cutaneous condition characterized by large, firm, blue or blue-black nodules.[7]: 701
- An epithelioid blue nevus is a cutaneous condition most commonly seen in patients with the Carney complex.[7]: 701
- A deep penetrating nevus is a type of benign melanocytic skin tumor characterized, as its name suggests, by penetration into the deep dermis 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 is advisable in some cases to help differentiate from invasive melanoma.[7]: 701
- An amelanotic blue nevus (also known as a "hypomelanotic blue nevus") is a cutaneous condition characterized by mild atypia and pleomorphism.[7]: 701
- A malignant blue nevus is a cutaneous condition characterized by a sheet-like growth pattern, mitoses, necrosis, and cellular atypia.[1][7]: 701