Giant bathing trunk nevi:

to cut or not to cut?

presented by

Henry Foong FRCP Edin

Ipoh, Malaysia

on March 20, 2006

Dermatologist, Foong Skin Specialist Clinic, Ipoh, Malaysia




Tannous ZS, Mihm MC Jr, Sober AJ, Duncan LM. Congenital melanocytic nevi: clinical and histopathologic features, risk of melanoma, and clinical management. J Am Acad Dermatol. 2005 Feb;52(2):197-203.

Dermatopathology Unit, Department of Pathology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114, USA.

Congenital melanocytic nevi occur in approximately 1% of newborns and are usually classified according to their size. Giant congenital melanocytic nevi are most simply defined as melanocytic nevi that are greater than 20 cm in largest dimension; whereas small congenital nevi are defined as melanocytic nevi less that 1.5 cm in largest dimension. Congenital nevi can exhibit distinctive histologic features that can help in differentiating them from common acquired nevi. Giant congenital melanocytic nevi are associated with an increased risk of the development of melanoma. On the other hand, there is evidence of an increased melanoma risk in patients with small congenital nevi. Nevertheless, the risk of malignant transformation in small congenital nevi and the lifetime melanoma risk in patients with small congenital nevi remain controversial. In large part due to inconsistency in the reported literature describing patients with congenital melanocytic nevi, the risk of melanoma in these patients remains unclear and consistent guidelines for clinical management do not exist. We review the literature and comment on the course of management for these patients at the Massachusetts General Hospital Pigmented Lesion Clinic.

De Raeve LE, Roseeuw DI. Curettage of giant congenital melanocytic nevi in neonates: a decade later. Arch Dermatol. 2002 Jul;138(7):943-7.

Department of Dermatology, Academic Hospital Vrije Universiteit Brussel, Brussels, Belgium.

BACKGROUND: Currently, there is tremendous uncertainty regarding how giant congenital melanocytic nevi (GCMN) should be treated. Our approach to patients with GCMN is based on 2 main considerations: (1) obtain an acceptable cosmetic result to decrease the psychosocial inconvenience to the patient, and (2) attempt to minimize the risk of malignancy. For the past 10 years we have treated GCMN by curettage in the neonatal period. We report our experience and results.

OBSERVATIONS: Sixteen neonates with GCMN were treated by curettage between 1990 and 2000. Biopsy specimens were obtained and the patients received close clinical follow-up. In most patients cosmetic and functional results were good, and, to date, no melanoma has been observed in this series.

CONCLUSIONS: Curettage offers an adequate alternative to surgical excision when performed during the first 2 weeks of life. Patients and parents are pleased with the cosmetic and functional results and thereby suffer less from the psychosocial inconvenience caused by these lesions. Careful long-term follow-up of these children is essential to monitor final cosmetic outcome and reduce the potential for malignancy.

Duke D, Byers HR, Sober AJ, Anderson RR, Grevelink JM. Treatment of benign and atypical nevi with the normal-mode ruby laser and the Q-switched ruby laser: clinical improvement but failure to completely eliminate nevomelanocytes. Arch Dermatol. 1999 Mar;135(3):290-6.

Dermatology Laser Center, Massachusetts General Hospital, Harvard Medical School, Boston, USA.

OBJECTIVE: To evaluate the effect of normal-mode and Q-switched ruby laser light (694 nm) on nevomelanocytes of benign, atypical, and congenital nevi.

DESIGN: Half of the lesion of each of 31 nevi was treated with either the Q-switched ruby laser or the normal-mode ruby laser or both; the other half of the lesion was covered with aluminum foil and was not treated.

SETTING: A university-affiliated, hospital-based laser center.

PATIENTS: Sixteen patients with a total of 31 melanocytic nevi were enrolled in the study.

INTERVENTIONS: All nevi were evaluated by at least 2 dermatologists to assess the degree of clinical atypia. Photographs were taken before and immediately after treatment and at each follow-up visit. The digital imaging system was used to evaluate the number of melanocytes in a measured length of basement membrane zone.

MAIN OUTCOME MEASURE: Three individual readings (number of melanocytes per unit length) were taken on both the control and treated halves and then compared to quantitate treatment effect. All analyses used averages from 3 measurements. A Student paired t test was used to compare the treated and untreated sides.

RESULTS: Sixteen (52%) of the nevi showed a clinically visible decrease in pigment on the treatment side at the 4-week follow-up visit.

CONCLUSION: No lesions had complete histologic removal of all nevomelanocytes. Therefore, 1 or 2 laser treatments are not sufficient to cause complete removal of a lesion either clinically or histologically.

Bittencourt FV, Marghoob AA, Kopf AW, Koenig KL, Bart RS. Large congenital melanocytic nevi and the risk for development of malignant melanoma and neurocutaneous melanocytosis. Pediatrics. 2000 Oct;106(4):736-41.

Ronald O. Perelman Department of Dermatology, New York University School of Medicine, New York, New York 10016, USA.

OBJECTIVE: To determine the risk for developing malignant melanoma and neurocutaneous melanocytosis (NCM) in patients with large congenital melanocytic nevi.

DESIGN: Follow-up data suitable for calculations were available on 160 patients in the New York University Registry of Large Congenital Melanocytic Nevi who had been free of known melanomas or NCM when entered into the Registry. The cumulative 5-year life-table risks for developing melanoma and NCM were calculated. The relative risk for developing melanoma, using a control general population reference group, was determined.

RESULTS: The 160 patients (median age at entry: 14 months) were followed prospectively for an average of 5.5 years. Three extracutaneous melanomas developed: 2 were in the central nervous system (CNS) and 1 was retroperitoneal. The 5-year cumulative life-table risk for developing melanoma was 2.3% (95% confidence interval [CI]:.8-6.6) and the relative risk was 101 (95% CI: 21-296). No melanoma occurred within a large congenital melanocytic nevus. Four patients developed manifest NCM, 2 with CNS melanomas. The 5-year cumulative life-table risk for developing NCM was 2.5% (95% CI:.8-7.2). Ten patients were excluded from the calculations because of preexisting disease on entry into the Registry: 5 with manifest NCM and 5 with melanomas (3 in large congenital melanocytic nevi, 1 in nonnevus skin, and 1 unknown primary).

CONCLUSIONS: Patients with large congenital melanocytic nevi are at increased risk for developing melanomas. There is also a significant increased risk for developing NCM. The high incidence of CNS involvement may influence decisions concerning treatment of the large congenital melanocytic nevi.

Hale EK, Stein J, Ben-Porat L, Panageas KS, Eichenbaum MS, Marghoob AA, Osman I, Kopf AW, Polsky D. Association of melanoma and neurocutaneous melanocytosis with large congenital melanocytic naevi--results from the NYU-LCMN registry. Br J Dermatol. 2005 Mar;152(3):512-7.

Oncology Section, Skin and Cancer Unit, New York University Medical Center, 550 First Avenue, H100, New York, NY 10016, USA.

BACKGROUND: Large congenital melanocytic naevi (LCMN), which develop in utero and are present in approximately one in 20,000 newborns, are associated with markedly increased risks of cutaneous melanoma, leptomeningeal melanoma and neurocutaneous melanocytosis (NCM).

OBJECTIVES: This study examined clinical characteristics associated with melanoma and NCM among patients with LCMN, and estimated the risk of developing melanoma and NCM in these patients.

METHODS: Two hundred and five LCMN patients enrolled in the New York University registry were studied. One hundred and seventy of these patients were followed prospectively. The remaining 35 patients had either melanoma at the time of entry into the registry (n = 6), or had insufficient follow-up information (n = 29). The outcome measures were the occurrence of melanoma and NCM. The associations between these outcomes and the clinical covariates (anatomical location of the LCMN, size of the LCMN, number of satellite lesions, family history of melanoma, patient sex and treatment) were assessed.

RESULTS: Four of 170 (2.3%) prospectively followed patients developed melanomas, representing a standardized morbidity ratio of 324. Among the entire cohort (n = 205), there were associations between increasing numbers of satellite naevi and the occurrence of melanoma (P = 0.04), and the presence of NCM (P = 0.06). Compared with patients who did not develop these diseases, median LCMN diameters were larger among patients who developed melanoma (49 vs. 39 cm) and NCM (55 vs. 46 cm).

CONCLUSIONS: In LCMN patients, increasing numbers of satellite lesions and larger LCMN diameters are associated with melanoma and NCM.


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