Dermatology Online Journal

Malignant melanoma arising in a nevus spilus
C Angit¹, N Khirwadkar², R M Azurdia¹
Dermatology Online Journal 17 (4): 10

1. Dermatology
2. Histopathology
Royal Liverpool and Broadgreen University Hospitals NHS Trust, Liverpool, United Kingdom

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Abstract

Malignant melanoma arising within a nevus spilus is rare. Nevus spilus is characterized by darkly pigmented macules and papules with background hyperpigmention. We report a 65-year-old woman who presented with a melanoma arising in a nevus spilus that had been present since birth.

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Introduction

Malignant melanoma arising within a nevus spilus is rare. Nevus spilus is characterized by darkly pigmented macules and papules with background hyperpigmention [1].

Case report

Figure 1	Figure 2

A 65-year-old woman was referred to our dermatology department for a suspicious pigmented lesion over her lower back. This lesion was present since birth and she had noticed a recent change in it with darkening of the pigmentation. She had skin type III. Her past medical history included chronic obstructive airway disease, osteoarthritis, hypertension, and psoriasis.

Examination revealed a large nevus spilus measuring 9 cm x 3 cm with a 5 mm black nodule on the upper border of this nevus (Figure 1) affecting the mid-lower lumbar area of the back. Dermatoscopic examination showed a blue-grey veil, irregular pigment network with dots and globules - highly suggestive of a malignant melanoma. The nodule was excised immediately.

Excisional biopsy (Figure 2) showed an asymmetrical melanocytic lesion consisting of junctional and dermal nests of atypical melanocytes. The melanocytes showed moderate cytological atypia with eosinophilic nucleoli. Nuclei with irregular nuclear contours were present. The mitotic activity was low. The appearances were those of a superficial spreading malignant melanoma in vertical growth phase with a Breslow thickness of 1.1 mm and Clark level III.

Discussion

Malignant melanoma arising within a nevus spilus is rare. Nevus spilus is characterized by darkly pigmented macules and papules with background hyperpigmention [1]. Nevus spilus does not appear to be a significant risk marker for melanoma. There was no significant difference in the prevalence of nevus spilus between patients with cutaneous melanoma and controls taken from general dermatology outpatients (5 out of 105; 4.5% vs. 14 of 106; 2.3%) respectively [2]. In addition, another observational study reported 2 patients among 946 patients with nevus spilus had transformed into melanoma [3].

The multistep process of neoplasia has been postulated in the development of melanoma from nevus spilus [4]. A close follow-up by sequential digital dermatoscopy and excision of lesions with dynamic changes may assist in the early detection of melanoma as suggested by an observational clinical study in which adult patients with unilateral segmental nevus spilus were monitored [5].

Conclusion

Based on the observations of the case reported, the potential of melanoma arising in nevus spilus must be considered. Patients with nevus spilus do not require regular clinic follow up but should be advised to monitor for any changes in their nevi by following the ABCD mole-watching advice.

References

1. Stewart DM, Altman J, Mehregan AH. Speckled lentiginous nevus. Arch Dermatol 1978;114;895-6. [PubMed]

2. Kopf A, Levine L, Rigel D et al. Congenital nevus-like-nevi, nevi spili and café-au-lait spots in patients with malignant melanoma. J Dermatol Surg Oncol 1985; 11: 275-80. [PubMed]

3. Breitkopf C, Ernst K, Hundeiker M. Neoplasms in nevus spilus. Hautarzt. 1996 Oct;47(10):759-62. [PubMed]

4. Rhodes AR, Mihm MC Jr. Origin of cutaneous melanoma in a congenital dysplastic nevus spilus. Arch Dermatol. 1990 Apr;126(4):500-5. [PubMed]

5. Haenssle HA, Kaune KM, Buhl T, Thoms KM, Padeken M, Emmert S, Schön MP. Melanoma arising in segmental nevus spilus: detection by sequential digital dermatoscopy. J Am Acad Dermatol. 2009 Aug;61(2):337-41. Epub 2009 Feb 23. [PubMed]

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