Dermatology: Practical and Conceptual Research Letter | Dermatol Pract Concept. 2025;15(3):5323 1 Eruptive Disseminated Spitz Nevi With Architectural Features of Clark/Dysplastic Nevus Giovanna Curi Campos1, Elizabeth Leocadia Fernandes1, Jan Lapins2, Karina Schultz2, Ricardo Silvestre Silva Macarenco3, Mariana Tavares Colferai4 1 Department of Dermatology, Taubaté University Hospital, Sao Paulo, Brazil  2 Department of Dermatology, Karolinska University Hospital and Karolinska Institutet, Stockholm, Sweden  3 Dermatology Service of the Municipal Health Authority, Apucarana, Paraná, Brazil 4 Department of Pathology of Israelita Albert Einstein Hospital, Sao Paulo, Brazil Key words: Spitz nevus, Disseminated, Eruptive, Dermatoscopy, Case report Citation: Curi Campos GC, Leocadia Fernandes E, Lapins J, Schultz K, Silva Macarenco RS, Tavares Colferai M. Eruptive Disseminated Spitz Nevi With Architectural Features of Clark/Dysplastic Nevus. Dermatol Pract Concept. 2025;15(3):5323. DOI: https://doi.org /10.5826/dpc.1503a5323 Accepted: April 12, 2025; Published: July 2025 Copyright: ©2025 Curi Campos 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: Giovanna Curi Campos, Department of Dermatology, Taubaté University Hospital, Sao Paulo, Brazil. E-mail: Giovanna.curicampos@hotmail.com   Introduction Spitz nevi can be classified into three variants: solitary, agmi- nated or segmental ,and eruptive disseminated (EDSN). The EDSN variant is exceedingly rare. EDSN typically manifests with an abrupt, eruptive onset, developing over a period of several months, followed by a slow progressive course, and eventually involution [1,2]. Case Presentation  The patient, a 52-year-old female, was admitted because of the sudden appearance of hundreds of lesions that had in- creased in number and size over the past 10 years. Initially, when the patient first developed these lesions, she underwent excision of a malignant melanoma in the left flank region, classified as superficial spreading melanoma with Breslow thickness 0.5 mm. In the ensuing years, the patient under- went approximately 50 excisions of nevi, the majority of which were histopathologically classified as dysplastic nevi. It is noteworthy that the patient had no history of Spitz nevi excision.  A physical examination revealed the presence of multiple macules and papules of varying sizes and colors, spanning a spectrum from light brown to dark brown and gray-brown or gray, distributed across the entire surface area of the skin, mostly on the trunk and proximal limbs, sparing the face and acral skin (Figure 1, A and B). In cases where there was a suspicion of melanoma, an excisional biopsy was con- ducted with the guidance of dermoscopy. The majority of lesions observed in the histopathological examination were composite melanocytic in nature, exhibiting interpapillary ridges extensions and papillary dermis fibroplasia. A discrete inflammatory infiltrate of lymphocytes was observed in the 2 Research Letter | Dermatol Pract Concept. 2025;15(3):5323 dermis. The infiltrate was observed to permeate the dermal component of the lesion. These characteristics are typically observed in Clark/dysplastic nevi. Furthermore, the mela- nocytic elements of these lesions exhibited spitzoid charac- teristics, namely, a large eosinophilic cytoplasm and with a good delimitation between cells3 (Figure 2A-C).  In the sub- sequent years, the pigmented lesions exhibited a gradual de- cline or complete resolution, with no new lesions emerging. Currently, only a minor subset of lesions persists. Discussion Fifteen of the lesions that were excised from the patient showed a histopathological picture of nevi, with cytological features of Spitz nevus and architectural features consistent with Clark/dysplastic nevus, also referred to as Spark nevus. This finding is considered unusual in the context of EDSN. Interestingly, although the present case was not tested for BRAF mutation status, in a recent study on benign and intermediate-grade melanocytic tumors with  BRAF  muta- tions and spitzoid morphology (BAMS), eight out of 36 cases had architectural features typical of Spark nevi, including plaque-like silhouettes with a fusion of rete ridges and lamel- lar fibroplasia [4]. The nevi observed in this patient (Figure 1C-F) lacked the typical clinical and dermatoscopic features associated with Spitz nevi,5 which may be explained by the mixture of histopathological features of Spitz and Clark nevi that we observed [6,7]. Figure 1. (A, B) Clinical: Among the large number of lesions, some were dark brown, while others were either noticeably lighter in color or exhibited a hint of gray, evidence that the patient gradu- ally developed new and darker lesions, while others seem to recede, with a lighter brown or gray element. Dermoscopy: (C, D) The most heavily pigmented lesions exhibit predominantly reticular lines that display a variegated brown and gray-brown coloration. (E, F) In contrast, in the lighter lesions, there are remnants of a light-colored reticular pattern. Figure 2. (A-C) Histopathology: A composite melanocytic lesion, exhibiting interpapillary ridges extensions and papillary dermis fibroplasia, characteristically for Clark/dysplastic nevus and the melanocytic elements exhibiting spitzoid characteristics with large eosinophilic cytoplasm and with a good delimitation between cells.   Research Letter | Dermatol Pract Concept. 2025;15(3):5323 3 Conclusion  This case presents features not previously described for EDSN, with an unusual clinical presentation and, in partic- ular, the histological presence of cytological features of Spitz nevus in combination with architectural features of Clark/ dysplastic nevus. 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