Observation | Dermatol Pract Concept 2011;1(1):6 21 Melanoma arising in a giant nevus spilus maculosus Alexander Stella, M.D.1, Katharina Ponholzer, M.D.1, Jessika Weingast, M.D.1, Michael Binder, M.D.1 1Department of Dermatology, Division of General Dermatology, University of Vienna, Vienna, Austria Key words: nevus spilus, large nevus spilus maculosus, malignant melanoma Citation: Stella A, Ponholzer K, Weingast J, Binder M. Melanoma arising in a giant nevus spilus maculosus. Dermatol Pract Concept 2011;1(1):6. http://dx.doi.org/10.5826/dpc.0101a06. editor: Harald Kittler, M.D. received: october 1, 2010; accepted: December 31, 2010; Published: october 31, 2011 Copyright: ©2011 Stella et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Funding: None. Competing interests: The authors have no conflicts of interest to disclose. All authors have contributed significantly to this publication. Corresponding author: Alexander Stella, M.D., Department of Dermatology, Division of General Dermatology, Medical University of Vienna, A-1090 Vienna, Austria. Email: alexander.stella@meduniwien.ac.at. Case report A 78-year-old Caucasian woman presented with an ulcer- ated nodule in the right pretibial region (Figure 1). The nod- ule measured 1 cm in diameter and was surrounded by an erythema. It had grown in a large pre-existing, congenital pigmented lesion that, according to the patient, existed since birth (Figure 2). The gigantic nevus was flat and speckled. It extended over the right leg and the right side of the abdo- men and the lower back, skipping the buttock and the back of the thigh, and crossed the midline (Figure 3). Close up it consisted of multiple dark-brown macules on a light brown, café-au-lait-like background (Figure 4). A punch biopsy of the nevus showed elongation of rete ridges and hyperpig- mentation of basal keratinocytes but no substantial prolif- eration of melanocytes (Figure 5). Histopathology of the nodule showed a nodular melanoma with an invasion thick- ness of 4.5 mm (Figure 6). on the basis of the clinical and pathologic findings we made the diagnosis of a melanoma arising in a giant nevus spilus maculosus. Figure 1. Close-up of eroded nodule with surrounding erythema. Melanoma arising in a nevus spilus is rare. There are two distinct types of nevus spilus characterized by macular or papular speckles, respectively. We report the case of a melanoma that arose in associa- tion with a giant nevus spilus maculosus. aBstraCt Dermatology PrACTICAL & CoNCEPTUAL www.derm101.com 22 Observation | Dermatol Pract Concept 2011;1(1):6 Figure 2. The nodule on the right leg appeared in association with a speckled lentiginous nevus (nevus spilus). Figure 3. Extension of the nevus spilus that crosses the midline. Figure 4. Close-up of nevus spilus maculosus. Figures 5a–e. Punch biopsy of the speckled lentiginous nevus. The biopsy was taken from the thigh. Mild acanthosis and hyper- pigmentation of basal keratinocytes is pres- ent but there is no marked proliferation of melanocytes. A B C D E Observation | Dermatol Pract Concept 2011;1(1):6 23 Discussion Malignant melanoma arising in association with a nevus spilus, also referred to as speckled lentiginous nevus, is rare [1,2]. In German, nevus spilus is also named “Kiebitzei- Naevus,” referring to the peculiar pattern of the nevus that resembles a lapwing’s egg (Figure 7). According to Happle there are two distinct types of nevus spilus [3,4]. Nevus spilus maculosus is flat and character- ized by dark brown spots on a light brown background. In this type of nevus spilus the background pigmentation his- topathologically corresponds to hyperpigmention of basal keratinocytes, and the dark spots are believed to be typified by junctional melanocytes arranged in nests. In the presented case a punch biopsy of the nevus did not show a prolifera- tion of melanocytes, but the biopsy was relatively small and sampling error cannot be excluded. Papular nevus spilus, on the other hand, is character- ized by dark brown papules or nodules on a light-brown background, although small dark spots may also be present [3]. Histopathologically, this type of nevus spilus shows the pattern of a superficial and deep congenital nevus with the presence of melanocytes in the papillary and reticular der- mis. The malignant potential of the papular type appears to Figures 6a–g. Histopathology of the ulcer- ated melanoma arising in the nevus spilus maculosus. Large and pleomorphic tumor cells are arranged in irregular nests and sheets in the dermis. A B C D F E G be lower than that of macular type of nevus spilus [3]. It is possible that the two different types of nevus spilus originate from different mutations. This would also explain the dis- similar malignant potential of either type of nevus [4]. As a possible differential diagnosis we also considered a partial unilateral lentiginosis (PUL), which seems to be a Figure 7. Four lapwing’s eggs [German: Kiebitz Eier]. Picture cour- tesy of Dr. Ernst Bauernfeind, Head Curator of the Bird Collection, Museum of Natural History, Vienna, Austria). 24 Observation | Dermatol Pract Concept 2011;1(1):6 mosaic manifestation of type 1 neurofibromatosis [5]. This rare condition was excluded on the basis of clinical findings because in PUL the background is normal and not hyper- pigmented and the body-midline is not crossed. In addition, our patient showed no signs of neurofibroma or café-au-lait macules [6,7]. Phacomatosis spilorosea, a subtype of phaco- matosis pigmentovascularis, could also be excluded because of the absence of telangiectasias [8]. We excluded the speck- led lentiginous nevus syndrome that is characterized by a speckled lentiginous nevus of the papular type and ipsilateral neurological abnormalities such as hyperhidrosis, muscular weakness and dysesthesia because such abnormalities were not present in our patient [9]. This case of a melanoma arising in a nevus spilus maculosus suggests that this type of nevus should be regu- larly observed by a dermatologist and patients should be instructed to perform self-examinations to detect changes as early as possible. references 1. Breitkopf C, Ernst K, Hundeiker M. Neoplasms in nevus spilus. Hautarzt 1996;47:759–62. 2. Borrego L, Hernandez Santana J, Baez o, Hernandez Hernandez B. Naevus spilus as a precursor of cutaneous melanoma: report of a case and literature review. Clin Exp Dermatol 1994;19(6):515– 17. 3. Vidaurri-de la Cruz H, Happle r. Two distinct types of speckled lentiginous nevi characterized by macular versus papular speck- les. Dermatology 2006;212(1):53–8. 4. Happle r. Speckled lentiginous naevus: which of the two disor- ders do you mean? Clin Exp Dermatol 2009;34(2):133–5. 5. Chen W, Fan PC, Happle r. Partial unilateral lentiginosis with ipsilateral Lisch nodules and axillary freckling. Dermatology 2004;209(4):321–4. 6. Serarsalan G. Partial unilateral lentiginosis with ipsilateral ocular nevus. J Eur Acad Dermatol Venereol 2007;21(2):281–3. 7. Happle r. Nevus spilus maculosus vs. partial unilateral lentigino- sis. J Eur Acad Dermatol Venereol 2007;21(5):713. 8. Happle r. Phacomatosis pigmentovascularis revisited and reclas- sified. Arch Dermatol 2005;141(3):385–8. 9. Happle r. Speckled lentiginous nevus syndrome: delineation of a new distinct neurocutaneus phenotype Eur J Dermatol 2002;12(2):133–5.