Blue nevus

Blue nevus
Other names	Blue neuronevus, dermal melanocytoma, nevus coeruleus, nevus bleu [1]
Blue nevus
Specialty	Dermatology
Symptoms	Single well-defined blue-black bump [2]
Complications	Rarely malignant transformation [3]
Types	Dendritic, cellular [2]
Causes	Unclear [3]
Diagnostic method	Visualisation, dermoscopy [4]
Differential diagnosis	Dermatofibroma, melanoma [3] [5]
Treatment	Monitoring, excision [3]
Prognosis	Good [3]
Frequency	Female>male [2]

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]

Classification

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}

• 
  Micrograph of a blue nevus showing the characteristic pigmented melanocytes between bundles of collagen. H&E stain
• 
  Blue nevus
• 
  Cellular blue nevus
• 
  Epithelioid blue nevus
• 
  Malignant blue nevus

See also

• List of cutaneous conditions
• List of genes mutated in pigmented cutaneous lesions

References

1. Rapini, Ronald P.; Bolognia, Jean L.; Jorizzo, Joseph L. (2007). Dermatology: 2-Volume Set. St. Louis: Mosby. p. 1722. ISBN   978-1-4160-2999-1.
2. Johnstone, Ronald B. (2017). "32. Lentigines and melanomas". Weedon's Skin Pathology Essentials (2nd ed.). Elsevier. p. 545. ISBN   978-0-7020-6830-0.
3. Austad, Steve S.; Athalye, Leela (2021). "Blue Nevus". StatPearls. StatPearls Publishing. PMID   31747181.
4. "Blue naevus". dermnetnz.org. Retrieved 21 October 2021.
5. Blue+Nevi at the U.S. National Library of Medicine Medical Subject Headings (MeSH)
6. Sreeremya, S. (17 April 2018). "Blue Nevus". International Journal of Molecular Biotechnology. 4 (1): 1–4. doi:10.37628/ijmb.v4i1.255 (inactive 11 July 2025).
7. James, William D.; Berger, Timothy G.; et al. (2006). Andrews' Diseases of the Skin: clinical Dermatology. Saunders Elsevier. ISBN   0-7216-2921-0.