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Table of Contents
Year : 2021  |  Volume : 39  |  Issue : 1  |  Page : 59-60

A case of seborrheic keratosis masquerading as malignant melanoma due to cutaneous cryotherapy

Department of Dermatology, Osaka City University Graduate School of Medicine, Osaka, Japan

Date of Submission13-May-2020
Date of Decision28-Jul-2020
Date of Acceptance25-Aug-2020
Date of Web Publication12-Feb-2021

Correspondence Address:
Dr. Kozo Nakai
Department of Dermatology, Osaka City University Graduate School of Medicine, 1-4-3 Asahimachi, Abeno-ku, Osaka 545-8585
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/ds.ds_44_20

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How to cite this article:
Moriki A, Nakai K, Iwaki Y, Sowa-Osako J, Sugawara K, Tsuruta D. A case of seborrheic keratosis masquerading as malignant melanoma due to cutaneous cryotherapy. Dermatol Sin 2021;39:59-60

How to cite this URL:
Moriki A, Nakai K, Iwaki Y, Sowa-Osako J, Sugawara K, Tsuruta D. A case of seborrheic keratosis masquerading as malignant melanoma due to cutaneous cryotherapy. Dermatol Sin [serial online] 2021 [cited 2021 Aug 3];39:59-60. Available from: https://www.dermsinica.org/text.asp?2021/39/1/59/309202

Dear Editor,

The clinical diagnosis of seborrheic keratosis (SK) is still a challenge for dermatologists, although it is a common benign skin tumor.[1] Among all, pigmented and irritated types of SK may closely resemble malignant skin tumor-like basal cell carcinoma or melanoma. Recent treatments of SK include hydrogen peroxide, nitric–zinc complex, and ablative laser therapy, but cutaneous cryotherapy, a classical treatment, appears to be preferred presumably because of its convenience.[2] Without histological confirmation, these treatments sometimes modify the clinical appearance and make the diagnosis of SK more difficult. We report a case of cryotherapy-modified SK which was clinically diagnosed as malignant melanoma and totally excised with 5 mm surgical margin.

An 82-year-old Japanese male was referred to our department with an asymptomatic black macule on the parietal region of the scalp that was notified 6 months ago. Before visiting our hospital, he had been treated by cryotherapy several times at a local clinic. Physical examination revealed a black macule of 20 mm × 27 mm in size with central white area on the parietal region of the scalp [Figure 1]a and [Figure 1]b. Dermatoscopic observation included not only globule-like structures but also asymmetric pattern of pigmented area, atypical pseudonetwork, and regression structure with blue-gray dots, implying malignant melanoma [Figure 1]c. These clinical observations led us to perform total excision with 5 mm surgical margin. Histopathology demonstrated hyperkeratosis, acanthosis, and papillomatosis of the epidermis [Figure 1]d. The keratosis was radially symmetric and contained several pseudo-horn cysts [Figure 1]e. Small round basaloid cells were increased within the epidermis. There were a few cells having small nuclei and inconspicuous cytoplasm in the epidermis. These cells expressed HMB45 and Melan-A, but minimal or no atypia was found [Figure 1]f and [Figure 1]g. A dense infiltration of cells including melanophages around the papillary dermis was seen in the regression area clinically observed.{Figure 1}

There are some reports dealing with cases of SK-like melanoma or melanoma-like SK, and dermatoscopic examination has been performed in most of these cases.[3] Although dermatoscope is a powerful tool to examine pigmented skin lesions, its magical technical terms sometimes derange the diagnosis. Network and pseudonetwork patterns with irregular structures are common in SK. However, we were confused with the regression structure with blue-gray dots. This finding appears to be found in some pigmented lesions with regression including SK and melanoma. Histologically, we speculated that the regression structure was created by cryotherapy, because cryotherapy is known to diminish melanosomes in keratinocytes[4] and evoke inflammation accompanied by dermal melanophage accumulation. In our case, biopsy should be considered to identify SK-like melanoma or melanoma-like SK. However, it should be noted that incisional biopsy is harmful to the prognosis of melanoma of the head and neck.[5] Therefore, we have excised the lesion with 5 mm surgical margin.

To our knowledge, this is the first case of melanoma-like SK induced by cryotherapy. Clinical diagnosis was deranged by dermatoscopic appearance. Total excision with 5 mm surgical margin might be overtreatment, but we consider that total excision is an adequate examination and/or treatment for melanoma-like SK of the head and neck.

Declaration of patient consent

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

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Conflicts of interest

There are no conflicts of interest.

  References Top

Mansur AT, Yildiz S. A diagnostic challenge: Inflamed and pigmented seborrheic keratosis. Clinical, dermoscopic, and histopathological correlation. Dermatol Online J 2019;25:13030/qt0w56m5hq.  Back to cited text no. 1
Wollina U. Seborrheic keratoses-The most common benign skin tumor of humans. Clinical presentation and an update on pathogenesis and treatment options. Open Access Maced J Med Sci 2018;6:2270-5.  Back to cited text no. 2
Carrera C, Segura S, Aguilera P, Scalvenzi M, Longo C, Barreiro A, et al. Dermoscopic clues for diagnosing melanomas that resemble seborrheic keratosis. JAMA Dermatol 2017;153:544-51.  Back to cited text no. 3
Burge SM, Bristol M, Millard PR, Dawber RP. Pigment changes in human skin after cryotherapy. Cryobiology 1986;23:422-32.  Back to cited text no. 4
Austin JR, Byers RM, Brown WD, Wolf P. Influence of biopsy on the prognosis of cutaneous melanoma of the head and neck. Head Neck 1996;18:107-17.  Back to cited text no. 5


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