Congenital Nevi



Patient Story





A small congenital nevus (Figure 163-1) was noted on this 6-month-old child by his new family physician during a routine examination. The parents acknowledged that it was present from birth and asked if it needed to be cut out. They were reassured that nothing needs to be done about it at this time.







Figure 163-1



Small congenital nevus found on the foot of a 6-month-old child. The parents were counseled that this nevus does not need to be excised for the prevention of melanoma. (Courtesy of Richard P. Usatine, MD.)







Introduction





Congenital melanocytic nevi are benign pigmented lesions that have a wide variation in presentation and are composed of melanocytes, the pigment-forming cells in the skin (Figures 163-1, 163-2, 163-3, 163-4, 163-5, 163-6, and 163-7).







Figure 163-2



Congenital nevus on the breast of a 24-year-old woman. It is verrucous, but entirely benign. (Courtesy of Richard P. Usatine, MD.)








Figure 163-3



A benign hairy congenital nevus on the upper buttocks of a 7-year-old boy. The parents requested a consult with plastic surgery to discuss removal. (Courtesy of Richard P. Usatine, MD.)








Figure 163-4



A speckled congenital nevus (nevus spilus) on the back of a young woman. (Courtesy of Richard P. Usatine, MD.)








Figure 163-5



Large bathing trunk nevus seen on the legs of this older child. (Courtesy of Jack Resneck, Sr., MD.)








Figure 163-6



Infant born with large bathing trunk nevus covering most of the back and chest. (Courtesy of the University of Texas Health Sciences Center, Division of Dermatology.)








Figure 163-7



Giant congenital bathing trunk nevus surrounded by satellite nevi in a 7-year-old Hispanic boy. The patient was referred to plastic surgery so that his parents might consider a staged removal of this large nevus. (Courtesy of Richard P. Usatine, MD.)







Synonyms






  • Garment nevus, bathing trunk nevus, giant hairy nevus, giant pigmented nevus, pigmented hairy nevus, nevus pigmentosus, nevus pigmentosus et pilosus, and Tierfell nevus.1
  • Tardive congenital nevus refers to a nevus with similar features to congenital nevi, but appears at age 1 to 2 years.






Epidemiology






  • Congenital melanocytic nevi develop in 1% to 6% of newborns and are present at birth or develop during the first year of life.1
  • In an Italian prevalence study of more than 3000 children ages 12 to 17 years, congenital melanocytic nevi or congenital nevus-like nevi were found in 17.5%; most (92%) were small (<1.5 cm).2
  • Congenital nevi are also seen in neurocutaneous melanosis, a rare syndrome characterized by the presence of congenital melanocytic nevi and melanotic neoplasms of the central nervous system.
  • The development of melanoma within congenital nevi (Figure 163-8) is believed to occur at a higher rate than in normal skin. Estimates range from 4% to 10%, with smaller lesions having lowest risk.1

    • In a systematic review, 46 of 651 patients with congenital melanocytic nevi (0.7%), who were followed for 3.4 to 23.7 years, developed melanomas, representing a 465-fold increased relative risk of developing melanoma during childhood and adolescence.3 The mean age at diagnosis of melanoma was 15.5 years (median: 7 years).
    • Patients with giant congenital melanocytic nevi appear to be at highest risk where subsequent melanoma has been reported in 5% to 7% by age 60 years.4 In one study, 70% of patients with a large congenital melanocytic nevi diagnosed with melanoma were diagnosed within the first 10 years of life.5
    • In a prospective study of 230 medium-size congenital nevi (1.5 to 19.9 cm) in 227 patients from 1955 to 1996, no melanomas occurred. The average follow-up period being 6.7 years to an average age of 25.5 years.6

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Jun 5, 2016 | Posted by in GENERAL & FAMILY MEDICINE | Comments Off on Congenital Nevi

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