Dermatology: Practical and Conceptual Letter to the Editor | Dermatol Pract Concept. 2024;14(1):e2024025 1 Synchronous Melanomas Within Nevus Spilus Federico Sansoni1, Ludovica Toffoli1, Alberto Zacchi3, Marina Agozzino1, Iris Zalaudek1, Nicola Di Meo1, Maria Antonietta Pizzichetta1,2 1 Dermatology Clinic of Trieste, Maggiore Hospital, University of Trieste, Trieste, Italy 2 Division of Medical Oncology - Preventive Oncology, National Cancer Institute, Aviano, Italy 3 Patology Department of Trieste, Cattinara Hospital, University of Trieste, Italy Citation: Sansoni F, Toffoli L, Zacchi A, et al. Synchronous Melanomas Within Nevus Spilus. Dermatol Pract Concept. 2024;14(1):e2024025. DOI: https://doi.org/10.5826/dpc.1401a25 Accepted: May 22, 2023; Published: January 2024 Copyright: ©2024 Sansoni et al. This is an open-access article distributed under the terms of the Creative Commons Attribution- NonCommercial License (BY-NC-4.0), https://creativecommons.org/licenses/by-nc/4.0/, which permits unrestricted noncommercial use, distribution, and reproduction in any medium, provided the original authors and source are credited. Funding: None. Competing Interests: None. Authorship: All authors have contributed significantly to this publication. Corresponding Author: Federico Sansoni MD, Dermatology Clinic of Trieste, Maggiore Hospital, University of Trieste, Trieste, Italy. Phone: +39 0403992056 Email: federicosansoni95@gmail.com Dear Editor, Nevus spilus (NS), also known as speckled lentiginous nevus, is a hyperpigmented macule or patch with superim- posed darker speckles that usually appears in infancy or childhood. It corresponds to a focal proliferation of melanocytes along the basal layer of the epidermis within a lentiginous background. The speckles display the histological features of different type of nevi such as junctional, intradermal, dys- plastic, Spitz and blue nevus. NS can be divided into 3 cat- egories regarding its dimension: small if >1.5 cm, medium from 1.5 to 19.9 cm and large if >20 cm [1,2]. The possible occurrence of melanoma within the nevus has been described in literature in about 40 cases to date, usually in patients aged around 50 years [3,4]. The presence of NS since birth, the dimension over 4 cm in diameter, the giant or zosteriform type are associated with higher risk to develop melanoma [4]. The frequency of this transformation is significant, but it appears to be lower than congenital nevi of the same size[4]. Herein we report the case of a 72-year-old male with 2 mel- anomas within a NS. He came to our department for his first skin examination, there was no personal or family history of skin cancers. On the right upper quadrant of the abdomen, we noticed a 5.5x1.8 cm speckled lentiginous nevus with a small hyperpigmented slightly palpable lesion measured 6x5mm. Dermoscopy showed within the lentiginous background a reddish area and an irregular pigmented network with some peripheral streaks (suggestive of melanoma) and comedo-like openings in the center (suggestive of seborrheic keratosis). Histological analysis of the biopsied sample revealed a superficially spreading melanoma with a Breslow thickness of 0.3mm (pT1a) with lichenoid regression and acanthosis. A further surgical excision was carried out with the complete removal of the NS. In the new skin sample an in-situ mela- noma outbreak was also found. Dermatological follow-up is now performed every 6 months. NS can be seen as a “melanocytic garden” in which dif- ferent lesions can grow based on the melanocyte differentia- tion pathway. Up to date, NS is usually not considered as a precursor of melanoma nevertheless, his malignant potential is described in literature. In the reported few cases of mel- anoma the most common types of melanoma were super- ficially spreading melanoma (68%) and nodular melanoma 2 Letter to the Editor | Dermatol Pract Concept. 2024;14(1):e2024025 (16%), in rare cases also melanoma in situ. Our case con- firms the presence of the most frequent histotype, but also highlights the occurrence of synchronous melanoma in situ. Only 4 cases of synchronous melanomas within a NS are reported [3-6] (Table 1). Dermoscopically, in our case the presence of melanoma was also partially hidden by seborrheic keratosis features, however considering the possibility of melanoma within a NS a biopsy was necessary to solve the diagnostic problem. Changing pigmented areas or nodules require selective biopsy for histological examination. In the case of a positive histological test, a complete excision of the entire NS is re- quired, in order to search for any multifocal melanomas such as in our case. References 1. Corradin MT, Cacitti V, Giulioni E, Patriarca MM, Vettorello A. Nevus Spilus: A Review of the Literature. SM Dermatology Journal. 2015;1(1):1-7. 2. Corradin MT, Zattra E, Fiorentino R, Alaibac M, Belloni-Fortina A. Nevus spilus and melanoma: Case report and review of the literature. J Cutan Med Surg. 2010;14(2):85-89. DOI:10.2310/7750.2009.08090. PMID: 20338124. 3. Brito MH, Dionísio CS, Fernandes CM, Ferreira JC, Rosa MJ, Garcia MM. Synchronous melanomas arising within nevus spilus. An Bras Dermatol. 2017;92(1):107-109. DOI: 10.1590 /abd1806-4841.20175230. PMID: 28225967. PMCID: PMC5312189. 4. Abecassis S, Spatz A, Cazeneuve C, et al. Mélanome sur naevus spilus: 5 observations [Melanoma within naevus spilus: 5 cases]. Ann Dermatol Venereol. 2006;133(4):323-328. DOI: 10.1016 /s0151-9638(06)70909-7. PMID: 16733445. 5. Meguerditchian AN, Cheney RT, Kane JM. Nevus spilus with synchronous melanomas: case report and literature re- view. J Cutan Med Surg. 2009;13(2):96-101. DOI:10.2310/7750 .2008.07090. PMID: 19298778. 6. Piana S, Gelli MC, Grenzi L, Ricci C, Gardini S, Piana S. Multifocal melanoma arising on nevus spilus. Int J Dermatol. 2006;45(11):1380-1381. DOI: 10.1111/j.1365-4632.2006. 03110.x. PMID: 17076737. Table 1. The features of the cases of synchronous melanomas within a nevus spilus in literature. Sex Age NS present since Dimensions of NS Location Breslow (mm) Note M6 28 unknow 5 cm left arm 0.7 mm; 0.7 mm; 0.3 mm no ulceration M4 32 infancy 10 cm Intergluteal groove 3.5 mm; 1.25 mm CDKN2A+ M5 60 childhood 15x10 cm Medial left calf 0.8 mm; 0.8 mm no ulceration M3 83 birth 27 cmx10 cm right arm and forearm 2.51 mm; 1.18 mm; in situ no ulceration Figure 1. (A) Nevus spilus of the right upper quadrant of the abdomen. Dermoscopy revealed macules and papules within a patch of tan- to-brown hyperpigmentation. In particularly, an hyperpigmented papule on the left inferior part of the nevus was noticed. (B) Dermoscopy revealed irregular pigmented network with a reddish area and some peripheral streaks. Moreover, SK features such as comedo-like openings and milia-like cysts were observed.