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Advances in dermatology and venereology Acta Dermato-Venereologica
Melanoma in Segmental Naevus Spilus: A Case Series and Literature Review
Monica C. T. BOOT-BLOEMEN 1, Wim J. A. DE KORT 2, Lidwine M. T. VAN DER SPEK-KEIJSER 3 and Nicole A. KUKUTSCH 4 * Departments of Dermatology, 1 Utrecht University Medical Centre, Utrecht, 2 Amphia Hospital, Breda, 3 Bravis Hospital, Roosendaal, and 4 Leiden University Medical Centre, Postbus 9600, NL-2300 RC Leiden, The Netherlands. * E-mail: N. A. Kukutsch @ lumc. nl Accepted Mar 15, 2017; Epub ahead of print Mar 15, 2017
Naevus spilus( NS) is characterized by congenital or acquired darkly pigmented macules and papules with background hyperpigmentation. It usually presents as a single lesion, but can be multiple, and may be distributed in a zosteriform pattern along a dermatome( 1). NS has also been described in association with an epidermal naevus and scoliosis( 1). The prevalence of NS in the general population is estimated to be 0.2 – 2.3 %. Frequent locations are the trunk and lower limbs( 2 – 5). NS occur in all skin types( 3). Somatic activating HRAS mutations were identified recently as the potential underlying cause of small single NS, which separates them from the congenital melanocytic naevi that show NRAS or BRAF mutations( 6, 7).
Malignant transformation of a NS is rare. In 1957, Perkinson described for the first time a melanoma appearing in NS in a patient with neurofibromatosis( 8). Since then, several cases have been reported of in situ melanoma developing in NS( 2, 4, 5, 9 – 30).
This article focusses on patients with segmental NS. They can show a flag-like, block-like or chequerboard café-au-lait pattern with superimposed naevi increasing in number during childhood and adolescence( 31). The prevalence of segmental NS or the incidence of melanomas occurring within the NS has not been well studied.
METHODS
Patients with segmental NS > 20 cm were collected from the database( January 2004 to December 2015) of the department of dermatology, Leiden University Medical Centre, the Netherlands. Clinical records were reviewed for initial presentation, changes during follow-up and results of biopsies or excisions. Photographic documentation was observed. Patients with NS-type congenital naevi, which were described recently as a specific subtype of congenital naevi were excluded( 32). A review of the literature( Pub- Med search 1936 – September 2015, Search((((((“ nevus spilous”) OR“ naevus spilous”) OR“ naevus spilus”) OR“ nevus spilus”) OR“ zosteriform lentiginous nevus”) OR“ speckled lentiginous nevus”) was performed.
RESULTS
Five patients with segmental NS > 20 cm were included; 2 men and 3 women with a mean age of 45.8 years at
Fig. 1. Patient 2.( a) Segmental naevus spilus on the left leg, melanoma indicated by the arrow.( b) Dermatoscopy of the melanoma on left leg. The scale is in mm.
first follow-up( Table SI 1 and Fig. 1). The back was the most common site of the NS. Two patients had NS smaller than 40 cm in diameter and 3 patients had NS larger than 40 cm. Two patients had congenital NS and 3 patients developed NS during childhood. Follow-up ranged from 10 to 120 months. Four invasive melanomas and one melanoma in situ appeared in 3 of our 5 patients. Three melanomas developed within the NS; patient 2 developed a melanoma within the NS on the leg, patient 3 developed 2 melanomas within the NS on the back and arm. In patient 3 a melanoma developed outside of the NS on the back. The melanoma in situ developed within the NS of patient 1 on the back. Melanomas were excised following the standard protocols, and histopathological investigation confirmed the diagnosis. In our cases, histopathology showed 2 superficial spreading melanomas; the subtypes of the other melanomas were unknown.
A review of the literature showed 11 other publications with segmental NS and melanoma( 5, 11 – 13, 19, 27, 28, 33 – 36). However, it sometimes remained unclear whether a large or segmental NS was described.
DISCUSSION
We describe here 5 patients with NS > 20 cm with a segmental distribution. Three of 5 patients developed
1 https:// www. medicaljournals. se / acta / content / abstract / 10.2340 / 00015555-2646
This is an open access article under the CC BY-NC license. www. medicaljournals. se / acta Journal Compilation © 2017 Acta Dermato-Venereologica. doi: 10.2340 / 00015555-2646 Acta Derm Venereol 2017; 97: 749 – 750