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Dermatology > BENIGN NEOPLASMS
Blue Nevi
Article Last Updated: Jan 4, 2007
AUTHOR AND EDITOR INFORMATION
Section 1 of 10  
Author: Rudolf R Roth, MD, Medical Director, Department of Dermatology, Penn Medicine at Radnor; Associate Professor of Clinical Dermatology, Department of Dermatology, University of Pennsylvania School of Medicine
Rudolf R Roth is a member of the following medical societies: American Academy of Dermatology and Association of Military Dermatologists
Coauthor(s):
Scott M Acker, MD, Associate Professor, Director of Dermatopathology, Departments of Dermatology and Pathology, University of Alabama at Birmingham
Editors: Terry L Barrett, MD, Director, Associate Professor, Department of Dermatology, Division of Dermatopathology and Oral Pathology, Johns Hopkins University School of Medicine; Michael J Wells, MD, Associate Professor, Department of Dermatology, Texas Tech University Health Sciences Center; Lester F Libow, MD, Dermatopathologist, South Texas Dermatopathology Laboratory; Catherine Quirk, MD, Clinical Assistant Professor, Department of Dermatology, Brown University; William D James, MD, Paul R Gross Professor of Dermatology, University of Pennsylvania School of Medicine; Vice-Chair, Program Director, Department of Dermatology, University of Pennsylvania Health System
Author and Editor Disclosure
Synonyms and related keywords:
nevus of Jadassohn and Tieche, blue neuronevus, dermal melanocytoma, common blue nevus, cellular blue nevus, chromatophoroma, melanofibroma
Background
Two clinically recognized variants of blue nevus exist: the common blue nevus and the cellular blue nevus.
Tièche, a student of Jadassohn, first described the common blue nevus in 1906. Earlier authors described similar lesions as chromatophoroma and melanofibroma. The common blue nevus is a flat to slightly elevated, smooth surfaced macule, papule, or plaque that is gray-blue to bluish black in color. Lesions are usually solitary and found on the head and the neck, the sacral region, and the dorsal aspects of the hands and feet.
The cellular blue nevus was first described as a variant of melanoma. Later, it was classified as a variant of blue nevus. Controversy still arises over the precise distinction of atypical cellular blue nevus from melanoma. The cellular blue nevus is a less common lesion but often clinically similar to the common blue nevus. These lesions tend to be large, usually measuring 1-3 cm in diameter. Lesions are elevated, smooth-surfaced papules or plaques that are gray-blue to bluish black in color. Lesions are usually solitary and found on the buttocks, the sacral region, and occasionally on the dorsal aspects of the hands and the feet.
Pathophysiology
Although definitive experimental evidence is lacking, blue nevi are believed to represent dermal arrest in embryonal migration of neural crest melanocytes that fail to reach the epidermis. Collections of melanocytes can be found in fetal dermis, but they involute during later gestation.
Because of the variation of blue nevi in different populations, a genetic predisposition has been suggested. However, familial cases of blue nevi are exceedingly rare.
The clinically noted blue color is due to the depth of melanin in the epidermis and the Tyndall effect. The Tyndall effect is the preferential absorption of long wavelengths of light by melanin and the scattering of shorter wavelengths, representing the blue end of the spectrum, by collagen bundles.
Common and cellular blue nevi are not associated with chromosomal aberrations, and they show fewer B-RAF mutations compared with congenital and acquired nevi.
Frequency
United States
Blue nevi are most frequently noted in Asian populations, where the prevalence is estimated to be 3-5% in adults. They are found in 1-2% of white adults and are rarely found in blacks. Blue nevi are uncommon at birth or in the first few years of life, with an estimated prevalence of less than 1 case per 1000 population.
International
The international incidence of blue nevi varies with the population examined.
Mortality/Morbidity
- Most cases remain entirely benign. Blue nevi usually persist unchanged throughout life and are asymptomatic.
- Rare cases of malignant melanoma have been reported arising in association with cellular blue nevi.
Sex
Blue nevi are twice as common in women than in men.
Age
Blue nevi may develop at any age but are usually noticed in the second decade of life or later.
History
- Once a blue nevus appears, it tends to remain unchanged throughout life. Occasionally, common blue nevi flatten and fade in color. These changes are evenly distributed throughout the lesion.
- Malignant change in cellular blue nevi may be heralded by a sudden increase in size and occasionally ulceration.
- Cases of eruptive blue nevi have been reported, some following skin trauma, such as sunburn.
Physical
- Blue nevi are usually smooth-surfaced, dome-shaped papules that slowly develop from a macule to a papule.
- Common blue nevi tend to be smaller than 1 cm, and cellular blue nevi tend to be larger than 1 cm.
- Blue nevi are most commonly found on the skin. Rare cases of common blue nevi have been reported in the vagina, the spermatic cord, the uterine cervix, the lymph node, the prostate, the oral mucosa, and the bronchus.
Causes
See Pathophysiology. Although blue nevi are most frequently seen on the skin, they have also been reported in the oral cavity, subungually, in lymph nodes, and in organs such as the brain, pulmonary tract, and prostate.
Dermatofibroma
Malignant Melanoma
Nevi of Ota and Ito
Nevi, Melanocytic
Tattoo Reactions
Other Problems to be Considered
Combined nevus (a nevus that contains 2 or more separate types of nevi, such as a blue nevus in combination with a compound nevus or a spindle cell nevus)
Congenital nevus
Foreign body
Deep penetrating nevus
Desmoplastic melanoma
Lab Studies
- Laboratory studies are not necessary.
Imaging Studies
- Imaging studies generally are not necessary; however, dermoscopy is a useful method for separating common blue nevi from a melanoma. The features seen with the dermatoscope include a characteristic homogeneous steel-blue area with no pigment network, no aggregated globules, and no branched streaks.
Histologic Findings
A histologic continuum exists from common blue nevi to cellular blue nevi.
In common blue nevus, a vaguely nodular collection of poorly melanized spindled melanocytes and deeply pigmented dendritic melanocytes within thickened collagen bundles is seen. Scattered melanophages are usually noted. No mitoses are present.
In cellular blue nevus, a well-demarcated nodule formed by fascicles and nests of tightly packed, moderately sized, spindled to oval melanocytes with scattered melanophages is seen. The lesion is centered in the reticular dermis; blunt-ended, bulbus extensions that extend into the subcutaneous fat may be noted. Occasional mitoses may be present, but significant cytologic atypia and areas of necrosis are absent. Often, a component of common blue nevus is seen within these lesions.
A number of variants of blue nevi with corresponding histologic changes have been described, including epithelioid blue nevus (classic description is with the Carney complex, but also is seen without this condition), atypical blue nevus, deep penetrating blue nevus, sclerosing blue nevus, and amelanotic blue nevus.
The term malignant blue nevus is synonymous with malignant melanoma arising in association with a cellular blue nevus or growing in a histologic pattern similar to that of a cellular blue nevus. These lesions typically have a pronounced cytologic atypia, hyperchromasia, necrosis, an increased mitotic rate, and an infiltrative growth pattern. Complete excision with a margin of healthy skin should be performed.
Medical Care
No medical therapy is available.
Surgical Care
- A biopsy should be performed on any changing pigmented lesion.
- For a solitary lesion, simple excision is usually curative. Rare cases of persistent blue nevi, manifesting as satellite lesions around the original excision site, have been reported. These must be distinguished from malignant blue nevus, and reexcision is recommended.
Consultations
Clinical experience with pigmented lesions is necessary to determine the proper diagnosis. Persons with unusual or many lesions may benefit from consultation with a dermatologist.
Complications
- Common blue nevi are clinically benign. Lesions tend to persist unchanged throughout life.
- Cellular blue nevi are usually clinically benign. Because of their large size, biopsy and excision tend to be performed more often on cellular blue nevi than on common blue nevi.
- Rare cases of malignant melanoma have been reported to arise in cellular blue nevi. Any change in these lesions is an indication for biopsy or excision.
Prognosis
- The prognosis of blue nevi is excellent.
Medical/Legal Pitfalls
- Failure to consider the diagnosis of malignant melanoma in a changing pigmented lesion is a pitfall.
Special Concerns
- Carney syndrome (complex)
- Carney syndrome (complex) is the rare association of blue nevi with other cutaneous and systemic findings. This condition is thought to arise in an autosomal dominant fashion.
- Synonyms include lentigines, atrial myxomas, mucocutaneous myxomas, and blue nevi (LAMB) and nevi, atrial myxomas, myxoid tumors (neurofibromas), and ephelides (NAME).
- Few to many blue nevi, ephelides, and mucocutaneous lentigines are found in approximately half the patients. Most often, they are noted on the head and the neck. Lesions may also be noted on the extremities and the genitalia. Lesions arise after birth and develop throughout life. Skin lesions usually precede the detection of cardiac myxomas.
- Patients with 2 or more clinical findings should undergo a complete evaluation for other associated findings. First-degree relatives of these patients should also undergo an evaluation.
- Additional associations reported with Carney syndrome (complex) include myxoid fibroadenoma of the breast, growth hormone producing pituitary adenoma causing acromegaly, pheochromocytoma, Sertoli cell tumor of the testes, myxoid uterine leiomyomas, acoustic neuroma, blue nevi, and psammomatous melanotic schwannoma.
- Familial multiple blue nevi
- From birth, multiple lesions are present on the head and the neck, the trunk, the extremities, and the sclera. This condition is not associated with other cutaneous or systemic findings.
- This condition is thought to arise in an autosomal dominant fashion.
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Blue Nevi excerpt Article Last Updated: Jan 4, 2007
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