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 Table of Contents  
Year : 2018  |  Volume : 5  |  Issue : 1  |  Page : 47-49

The appearance of eruptive seborrheic keratoses over linear verrucous epidermal nevus − A report

Department of Dermatology and STD, JSS Medical College & Hospital, JSS University, Mysore, Karnataka, India

Date of Web Publication29-May-2018

Correspondence Address:
Poovanur Sadasivam Subramaniam Ranugha
Department of Dermatology and STD, JSS Medical College & Hospital, JSS University, Mysore, Karnataka
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/Pigmentinternational. Pigmentinternational

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Even though seborrheic keratosis (SK)-like histopathological change has been reported within verrucous epidermal nevi (VEN), SKs developing over epidermal nevi has not been described in the past, hence this report. A 50-year-old female presented with asymptomatic pigmented skin lesions over the right half of the body since birth and the appearance of new itchy raised lesions on these of 3 months duration. On examination, multiple verrucous pigmented papules and plaques, along the Blaschko’s lines, were seen involving the right side of the body. Multiple discrete hyperpigmented plaques with a rough surface were seen scattered overlying the linear lesions. There were no similar lesions on the normal skin elsewhere. Investigations for internal malignancy were negative. Biopsy from the linear lesions was suggestive of VEN, while that from the new onset verrucous plaques was consistent with SK. Activating fibroblast growth factor receptor 3 mutations have recently been detected in SKs and VEN. This might explain the colocalization of these in our patient.

Keywords: Colocalization, fibroblast growth factor 3 mutations, seborrheic keratoses, verrucous epidermal nevi

How to cite this article:
Ranugha PS, Betkerur JB, Savitha TG, Veeranna S, Basavaraj V. The appearance of eruptive seborrheic keratoses over linear verrucous epidermal nevus − A report. Pigment Int 2018;5:47-9

How to cite this URL:
Ranugha PS, Betkerur JB, Savitha TG, Veeranna S, Basavaraj V. The appearance of eruptive seborrheic keratoses over linear verrucous epidermal nevus − A report. Pigment Int [serial online] 2018 [cited 2022 Sep 28];5:47-9. Available from: https://www.pigmentinternational.com/text.asp?2018/5/1/47/233464

  Introduction Top

Epidermal nevi are circumscribed hamartomatous lesions arising from the embryonic ectoderm at birth or during childhood. Seborrheic keratoses (SKs) are the multiple benign tumors of keratinocytes, which usually appear in middle age. We describe here a 50-year-old female with a rare colocalization of SKs over verrucous epidermal nevi (VEN).

  Case report Top

A 50-year-old female presented with asymptomatic, pigmented lesions distributed unilaterally along the right half of her body since birth. Three months previously, she developed a itchy raised lesions over these. Her medical and family history was unremarkable. On examination, there were multiple pigmented papules, coalesced at some areas to form plaques, arranged in a linear fashion along the Blaschko’s lines, involving the right side of the chest, abdomen, back [Figure 1], and right upper limb. Multiple discrete hyperpigmented rough surfaced plaques, resembling verruca vulgaris, were seen scattered over these linear lesions [Figure 2]. There were no similar lesions in other areas. Skin biopsy from the hyperpigmented papule showed focal orthokeratosis, mild acanthosis, and papillomatosis with broad rete ridges, consistent with VEN. Skin biopsy from the discrete warty papule showed thick orthokeratosis, focal parakeratosis, acanthosis, papillomatosis, pseudohorn cysts [Figure 3], and mild perivascular lymphocytic infiltrate in the superficial dermis, consistent with SK. Her routine blood investigations were normal. A computed tomographic scan of the abdomen and pelvis was normal, and upper gastrointestinal endoscopy and biopsy did not reveal any evidence of malignancy. With the aforementioned clinical and histopathological findings, a diagnosis of SKs over VEN was made. Because the SK lesions were itchy, they were removed using radiosurgery, following which the patient was symptomatically better.
Figure 1: Epidermal nevus along Blaschko’s lines involving the right back with a few scattered verrucous lesions overlying these on the upper back

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Figure 2: Multiple discrete verrucous plaques overlying the nevus on the right arm

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Figure 3: Histopathology of the discrete warty lesion over the right arm showing acanthosis, papillomatosis, pseudohorn cysts, and a flat lower margin of the tumor

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  Discussion Top

VEN are congenital, noninflammatory cutaneous hamartomas composed of keratinocytes. They are characterized by localized or diffused closely set skin-colored, or brown, or gray-brown papules, which may coalesce to form well-demarcated papillomatous plaques.[1] Linear configurations along Blaschko’s lines or along relaxed skin tension lines are common. They probably comprise an abnormal clone of cells, reflecting genetic mosaicism arising from a somatic mutation.[2]

SKs are sharply demarcated gray-brown to black raised lesions, which may be covered with greasy scales. Though there is a predilection for the chest, interscapular region, waistline, and forehead, they may occur on any part of the body except the palms and soles. Multiple SKs may sometimes assume a patterned arrangement including linear, blaschkoid, nevoid, dermatomal, along skin cleavage lines, and as a raindrop pattern.[3],[4] In our patient, the lesions were discrete, scattered, and unilateral over the epidermal nevi.

Although more than 10 different histological patterns have been recognized in VEN, in over 60% of patients, there was hyperkeratosis, with papillomatosis of relatively flat and broad type, together with acanthosis. There is a thickening of the granular layer and often a slight increase in basal melanin pigment. This is the so-called “common type” of epidermal nevus; a similar picture was seen in our patient. Less frequently, the histological pattern resembles acrokeratosis verruciformis, epidermolytic hyperkeratosis, or SK.[5]

VEN with a SK-like histopathology often have thin, elongated rete ridges with “flat bottoms,” a feature not usually seen in SKs. In contrast, SKs usually show hyperkeratosis, acanthosis, and papillomatosis with a flat lower margin of the tumor with a normal epidermis on both sides.[5] Focal keratinization may occur within the mass of immature cells to produce horn cysts, as seen in our patient.

There have been sporadic reports over the years of tumors developing within epidermal nevi such as basal cell carcinoma, intraepithelial carcinoma, squamous cell carcinoma, adnexal carcinoma (malignant eccrine poroma), and keratoacanthoma. These tumors are seen commonly over sebaceous or apocrine nevi than VEN.[6] Johnson et al. described the occurrence of multiple pilomatricomas in and around epidermal nevi in a 3-year-old child.[7] A colocalization of SK and junctional nevus has been reported.[8] To the best of our knowledge, there is no report of SKs developing over VEN.

Somatic fibroblast growth factor receptor 3 (FGFR3) mutations are found in low-grade malignant bladder tumors, wherein they often occur in association with phosphatidylinositol 3-kinases isoform α(PIK3CA) mutations. Hafner et al. have found PIK3CA and/or FGFR3 mutations in 42% of epidermal nevi and in 42% of SKs in their study.[9] The presence of similar mutations might explain the colocalization of VEN and SKs in our patient. Mutational study was not performed in our patient. The details of the involved signaling pathways in the mutant keratinocytes leading to the formation of acanthotic skin tumors is only marginally known.[9] The colocalization of cutaneous tumors in the areas of mosaicism, as seen in our patient, needs further research.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

  References Top

Thomas VD, Snavley NR, Lee KK, Swanson NA. Benign epithelial tumours, hamartomas and hyperplasias. In: Wolff K, Goldsmith LA, Katz SI, Gilchrest BA, Paller AS, Leffell DJ, editors. Fitzpatrick’s Dermatology in General Medicine. 8th ed. United States: The Mc-Graw Hill Companies Inc; 2008. p. 1319-25.  Back to cited text no. 1
Moss C, Shahidullah H. Naevi and other developmental defects. In: Burns T, Breathnach S, Cox N, Griffiths C, editors. Rook’s Textbook of Dermatology. 8th ed. West Sussex, UK: Blackwell Publishing Ltd; 2010. p. 18. 5.  Back to cited text no. 2
Zhang RZ, Zhu WY. Seborrheic keratoses in five elderly patients: An appearance of raindrops and streams. Indian J Dermatol 2011;56:432-4.  Back to cited text no. 3
[PUBMED]  [Full text]  
Mabuchi T, Akasaka E, Kondoh A, Umezawa Y, Matsuyama T, Ozawa A. Seborrheic keratosis that follows Blaschko’s lines. J Dermatol 2008;35:301-3.  Back to cited text no. 4
Weedon D. Tumors of the epidermis. In: Weedon’s Skin Pathology. 3rd ed. China: Elsevier Ltd.; 2010. p. 669.  Back to cited text no. 5
Affleck AG, Leach IH, Varma S. Two squamous cell carcinomas arising in a linear epidermal naevus in a 28-year-old female. Clin Exp Dermatol 2005;30:382-4.  Back to cited text no. 6
Johnson LM, Newell B. Multiple large pilomatricomas in the setting of diffuse epidermal nevi. Pediatr Dermatol 2011;28:74-6.  Back to cited text no. 7
Requena L, Sánchez M, Requena C. Simultaneous occurrence of junctional nevus and seborrheic keratosis. Cutis 1989;44:465-6.  Back to cited text no. 8
Hafner C, López-Knowles E, Luis NM, Toll A, Baselga E, Fernández-Casado A et al. Oncogenic PIK3CA mutations occur in epidermal nevi and seborrheic keratoses with a characteristic mutation pattern. Proc Natl Acad Sci U S A 2007;104:13450-4.  Back to cited text no. 9


  [Figure 1], [Figure 2], [Figure 3]


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